Analyte stability & freeze-thaw information-1.xls

ANALYTE STABILITY & FREEZE-THAW INFORMATION (assembled by Elaine Gunter, Specimen Solutions, LLC) Proteases: trypsin, chymotrypsin, kallikrein, thrombin Protein degradation during prolonged storage represents a unique problem that may introduce bias when existing biobank resources are applied to future putative biomarker analyses. Plasma samples should be stored at - 70 C or lower for LTS.
Presentation at BRN Symposium 2010. http://biospecimens.cancer.gov/meeting/brnsymposiu Some fibrinogen peptides are m/2010/docs/Zimmerman%20BRN%20Protein%20Ststable up to to F/T, others ability%20Studies.pdf Assessment of protein stability C-reactive protein. D-dimer, plasmin-alpha2-antiplasmin complex, degradation over time for the Thromb Haemost. 2001 Dec;86(6):1495-500. Measured in frozen plasma samples stored at -70 Longitudinal stability of coagulation, fibrinolysis, and fibrinogen
degrees C on LN2 for months or up to 6 years inflammation factors in stored plasma samples.
From 1-6 hr after thawing, no significant difference in marker levels. In FVII activity Anesth Analg 2006: 103(4)969-74. Thawing procedures and the time course of clotting factor monomers, D-dimers; α-1 antiplasmin, Fresh plasma stored at - 40C for at least 8 wk. activity in fresh-frozne plasma: controlled laboratory 20 units collected, initially measured, kept 1 dat @ 4 Mean levels not statistically Transfusion 2003; 43:873-7. Vitamin K-dependent C, stored 1 wk @ -20 C thawed, stored another wk @ different. Levels remained coagulation factors and fibrinogen levels in FFP and fibrinogen in fresh-frozen plasma
remain stable upon repeated freezing and thawing.
Breast cancer biomarker generated in complement activation; all specimen handling operations should https://www.cambridgebiomedical.com/media/PDFLibr be carried out at 4 C to avoid generating C3a. Freeze Avoid repeated F/T, ary/TechBriefs/C3a%20des%20Arg%20in%20Plasma immediately, preferred frozen for < 3 D before Biomedical kit insert.
a number of stabilzers used for prepared LDH solutions, e.g., trehalose and borate, glycine, polyethylene glycols, sucrose, maltodextrinClin Chem 1983;29(5):832-5. Creatine Kinase and Storage @ -90 C has no effect on total or isoenzyme lactate dehydrogenase: Stability of isoenzymes and Creatine Kinase and LDH isoenzymes activity for LDH or CK as long as not thawed to 37 C
their activity in stored frozen plasma and prostatis tissue extracts and effect of sample dilution.
Collected serum subdivided into 3 parts: 1st analyzed immediately, 2nd stored @ -20 C and analyzed after 30 d; the 3rd stored @ -20 C and analyzed after 50 d. Scand J Lab Anim Sci Suppl 1 1998; 25: 2059. Creatine Kinase and LDH isoenzymes The total CK and LDH activities were stable in frozen
Stability of Ck- and Ldh-isoenzyme values in minipig samples; thawed results equivalent to initial serum under different storage conditions.
Serum samples were frozen @ -20 & -70 C, and then thawed up to six times.According to the Arrhenius calculation, MMP-7 showed excellent stability, at least 5 years at -20°C and several 100 years at - 75°C. The VEGF-receptor maintains 90% of its initial TIMP-1 was stable, even concentration at -20°C over 3 months, and decades after six freeze/thaw cycles. at -75°C. TIMP-1 and VEGF showed poor stability with cryopreservation, even at -75°C. The stability of the concentration of MMP-7 MMP-7, TIMP-1, VEGF or VEGF-receptor in biobanking is highly variable, and this should be taken into account in the interpretation of results. A temperature -20°C is unsuitable for prolonged Clin Chem Lab Med. 2011 Feb;49(2):229-35. Epub storage of the biomarkers investigated, and repeated significantly. Decreases in 2010 Dec 1. Impact of cryopreservation on serum thawing of sera is not recommended. VEGF is
concentration of matrix metalloproteinases (MMP)-7, especially unstable and should be quantitated
dramatic, even after the first TIMP-1, vascular growth factors (VEGF) and VEGF- using serum that has never been frozen.
Delayed storage of CSF led to changes in prostaglandin D-synthase derived peptides as well as to increased levels of certain amino acids and metabolites. The changes of metabolites, amino acids and proteins in the delayed storage study appear to be related to remaining white blood cells. Our recommendations are to centrifuge CSF samples transthyretin peptide levels immediately after collection to remove white blood (due to trypsin digestion]. F/T J Proteome Res. 2009 Dec;8(12):5511-22. The effect Polymeric proteins such as transthyretin cells, aliquot, and then snap-freeze the supernatant cycles should be avoided if at of preanalytical factors on stability of the proteome in CSF in liquid nitrogen for storage at -80 degrees C.
and selected metabolites in cerebrospinal fluid (CSF).
serum and cerebrospinal fluid carrier of the thyroid http://www.uscnk.us/pdf/20091014105437.pdf. Uscn hormone thyroxine (T4); also 1:1 complexes with Life Sciences ELISA Kit insert for Rat Serum Other markers: Interleukin-6 (IL-6) and TNF-α levels remained stable for at least 6 h in timely separated plasma but not in unseparated plasma 4 h after blood draw, in which IL-6 was decreased by mean 14.3% and TNF-α increased by mean 9.6%. Leptin was unchanged in both conditions, presumably due to the involvement of blood cells in the release and clearance of IL-6 and TNF-α but not of leptin. Interleukin-6 and leptin were not affected by freezing and thawing for their stable α-helical structure, while TNF-α concentration increased by 17.0% after 3 cycles and by 23.9% after 6 cycles due to the unstable β–pleated sheet structure.[8] Delayed (overnight) separation and short-term frozen-storage h in unseparated sera stored affected plasma but not serum IL-7 concentration.[9] at 4°C or in separated sera Hepatocyte growth factor (HGF), also a glycoprotein stored at room temperature, of 190 kDa heterodimer, remained stable in serum after 20 freeze-thaw cycles, or after 4-months of frozen storage, but increased by 20% after 10- months of frozen storage, which was possibly http://www.medscape.com/viewarticle/564090_4. ascribable to interassay variation, release of HGF Medscape Today: Serum Thyroglobulin Stability for from binding serum proteins, and some mechanism of storage. Compared with samples separated within 1 h, serum HGF was not altered when whole blood was stored for 24 h at 6°C before or 6 h at room temperature after separation, but increased when whole bloo Tg is stable for at least 24 hr in unseparated sera @ http://labmed.ascpjournals.org/content/38/10/618.full.p 4 C or separated sera @ RT, but not in sera df (Science) Serum thyroglobulin stability for undergoing even a short period of frozen storage.
Lab has determined that insulin is stable 5X F/T [other http://www.cdc.gov/nchs/data/nhanes/nhanes_07_08/ glu_e_met_insulin.pdf. Human insulin immunoassay.
Glycoproteins [ e.g., α-1 acid glycroprotein, thyroglobulin] Sensitive to freeze/thaw cycles in a -20 C frost-free [Given that RBCF must be stabilized with asorbic acid preservative!] Whole blood hemolysates less stable than intact whole blood; plasma folate less cycles (exposed to ambient Clinical Laboratory News, Jan 2011, 8-10. Folte: Clinical Utility of Serum & Red Blood Cell Analysis Various assay kit inserts. Also: http://repository.unm.edu/bitstream/handle/1928/6875/Norman_Ornelas%20Final%20Paper.pdf?sequence=1 Samples split & stored at -20 & -70 C for 1,3,6,& 12 . Stability of abnormal D-dimer levels in platelet-poor mo. Stable on storage at either temperature.
In vitro D-dimer stability in plasma is widely assumed, but has not yet been documented by systematic studies using samples covering a wide range of D-dimer. We investigated the short- and long-term stability of D-dimer in clinical citrated plasma samples with normal and pathological levels. The short-term stability was analysed by measuring D-dimer fresh, after storage of plasma for 4 hours at room temperature (RT) and after an additional 24 h storage at +2 to +8 degrees C (n=40). Long-term stability samples (n=40) were measured fresh and after storage for 19, 25 and 36 months at < or =-60 degrees C. The effect of repeated freezing was analysed by measuring samples (n=50) fresh and after four consecutive freeze-thaw cycles. D-dimer was measured on the BCS System using the INNOVANCE D-Dimer assay (Siemens Healthcare Diagnostics Products GmbH, Marburg, Germany). D- consecutive freeze-thaw dimer values at baseline ranged from 0.23-22.2 mg/l cycles. Repeated freezing FEU. The mean percentage change after storage for did not significantly alter D- Thromb Haemost. 2010 Feb;103(2):461-5. Epub 2009 4 hours at RT and additional 24 hours at +2 to +8 dimer values (mean change Nov 13. Long- and short-term in vitro D-dimer stability degrees C was +3.8% and +2.7%, respectively. The mean percentage change after frozen storage for 19, 25 and 36 months at < or =-60 degrees C was -1 1.7%, -4.8% and -9.3%, respectively. The small decrease of D-dimer values after frozen storage was not time- Endogenous LH, FSH, TSH, growth hormone, prolactin and insulin were measured by radioimmunoassay in human plasma samples stored at 4°, 20° and 37° for up to 8 days or repeatedly frozen and thawed. At 4°, the concentrations of all Clinical Biochemistry 1980 13(4):151-5. Effect of time, hormones were stable for at least 8 days; at 20° only All the hormones except temperature and freezing on the stability of LH, FSH and TSH were stable for 8 days; at 37° only insulin were stable during 5 immunoreactive LH, FSH, TSH, growth hormone, All contemporary assays detected significantly lower Clinical Chemistry and Laboratory Medicine. Volume TSH and increased FT4 and FT3 concentrations in 48, Issue 3, Pages 409–412 Stability of serum the stored samples after 8-11 yr @ -80 C.
thyroid hormones following 8–11 years of cold storage 3X F/T no effect on CHOL, retinol & carotenoids, & most Clinical Chemistry 47: 139-142, 2001. Effects of repeated freeze-thaw cycles on concentrations of variability. [Driskell 17X F/T cholesterol, micronutrients, and hormones in human A majority of analytes showed no significant changes until 30 freeze–thaw cycles. After 30 freeze–thaw cycles, the largest percent change was observed for free fatty acids (+32%), AST (+21%), and Cell Preservation Technology. Volume: 6 Issue 3: triglycerides (−19%). Human plasma can go through September 6, 2010. Evaluation of Freeze–Thaw vitamin E, aspartate aminotransferase several freeze–thaw cycles before analysis without Cycles on Stored Plasma in the Biobank of the influencing sample integrity for the selected analytes.
average decreases of 2.0% per year for total cholesterol over 7 years and 2.8% per year in Clin Chem. 2000 Mar;46(3):351-64.Estimating the triglycerides for the first 5 years. HDL-cholesterol long-term effects of storage at -70 degrees C on decreased by 1.3% per year, but this change was not cholesterol, triglyceride, and HDL-cholesterol Int J Epi 2008:37:234-44.The UK Biobank sample apolipoprotein B, cholesterol, creatinine Stored at -20, -40, -80, -180 C for up to 6 years. handling and storage protocol for the collection, kinase, creatinine,k fibrinogen, HDL-C, Degradation detected in some samples at -20 & -40, processing, and archiving of human blood and urine. simultaneously investigated the stability of 24 analytes (a) after prolonged contact of plasma and serum with blood cells and (b) after immediate separation of plasma and serum (centrifuged twice at 2000g for 5 min). We verified biochemical mechanisms of observed analyte change by concomitant measurement of pH, PCO2, and PO2. Hemolysis was qualitatively and semiquantitatively assessed. All specimens were maintained at room temperature (25 °C) and analyzed in duplicate 0.5, 4, albumin, alkaline phosphatase (ALK), aspartate aminotransferase (AST), 8, 16, 24, 32, 40, 48, and 56 h after collection. Fifteen of 24 analytes in plasma and serum maintained in direct bilirubin, total bilirubin, calcium, contact with cells showed clinically relevant changes, with the degree of change more pronounced in most plasma specimens. All analytes in plasma and serum immediately separated from cells after collection dehydrogenase (LD), Mg2+, Pi, K+, Na+, Conclusion: Storage of uncentrifuged specimens Clinical Chemistry. 2002;48:2242-2247. Stability total protein, triglycerides, uric acid, and beyond 24 h caused significant changes in most Studies of Twenty-Four Analytes in Human Plasma analytes investigated because of (a) glucose N=25 stored at -20 C and reassayed on days Clin Chem 1984; 30(1), 114-5. Freeze-thaw stability of 3,4,8,16,22. N=74 specimens stored at 4 C and transferrin and reference values obtained bykinetic nephelometryhttp://www.tricitieslab.com/Files/TestUpdates/Gliadin%20Antibodies.pdf. Anti-gliaden test for gluten-sensitive Anti-gliadin antibodies IgA, IgG in serum Lipoprotein a 19% in serum stored 3 yr @-70C; 30% increase in serum Ca Epi Biomarkers Prev 2005: 141899-907. Design testosterone in samples stored @ -80 c Lpa 25% decrease after 2X F/T to -20C, 23% Options for Molecular Epidemiology Research Within Demography, 44(4) Nov 2007: 899-925. What a drop can do: Dried Blood spots as a minimall invasive no evidence of deterioration method for integrating biomarkers int population- CRP was measured in serum samples at the baseline and in thawed plasma samples after an average storage period of 13.8 years. Geometric means of CRP were 0.25 mg/L and 0.59 mg/L before J Epi Vol. 17 (2007) , No. 4 pp.120-124. Comparison and after storage, respectively. The CRP values were of C-reactive Protein Levels between Serum and significantly higher after long-term frozen storage Plasma Samples on Long-term Frozen Storage after a Comparable results were obtained for plasma (heparin and EDTA treated) and serum samples, and levels were unaffected by delays in sample Clin Diagn Lab Immunol. 2003 July; 10(4): 652–657. processing and storage temperature. CRP levels Analytical Performance of a Highly Sensitive C- were also unaffected by up to seven freeze-thaw Reactive Protein-Based Immunoassay and the Effects of Laboratory Variables on Levels of Protein in BloodAnn Clin Biochem 2008;45:575-584 . Simultaneous determination of guanidinoacetate, creatine and . stable in urine for up to seven freeze thaw
creatinine in urine and plasma by un-derivatized liquid Br J Nutr. 2010 Sep;104(5):629-32. Epub 2010 Apr 26. Temporal reproducibility of taurine measurements is not affected by freeze–thaw cycles
in frozen serum of healthy postmenopausal women.
H. pylori Test. Serum or plasma samples may be . frozen and
http://www.fishersci.com/wps/downloads/segment/Hea thawed repeatedly.
OPG is stable at –20 C in serum and in EDTA, citrate, and heparin plasma, and also at 4 C for up to 14 d; Three freeze-thaw cycles did not affect recovery of sample from serum, EDTA plasma, or citrate plasma, although recovery was significantly reduced in heparinized plasma. In one study, sRANKL was stable at up to four freeze-thaw cycles in serum and The Journal of Clinical Endocrinology & Metabolism heparinized plasma (41). Another study showed that collection of sample on Li-heparin and storage for Osteoprotegerin and Receptor Activator for Nuclear Osteoprotegerin and Receptor Activator over 6 months at –70 C led to significant loss of Factor ; KB Ligand: Clinical Utility in Metabolic Bone Disease AssessmentProteome Science 2009, 7:15. Development of no change in clusterin levels after five freeze/thaw reverse phase protein microarrays for the validation of clusterin, a mid-abundant blood biomarker Advances in Chromatographic Techniques for freeze-thaw cycles demonstrate protein interference
Therapeutic Drug Monitoring. Immunoassays for Therapeutic Drug Monitoring. CRC Press 2010Current standards for the storage of human samples metabolic analysis of human serum
in biobanks. Genome Medicine 2010, 2:72 (5 October and urine for large scale population
.http://genomemedicine.com/content/pdf/gm193.pdf Post-collection, pre-measurement variables affecting Measuring VEGF in the urine, as opposed to serum
or plasma, is preferable
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2367114Comparison of Two Methods to Determine Plasma Two freeze-thaw cycles decreased activity by over
Bile Acid in Healthy Birds. J Avian Med Surg . 17(1), J Lipid Res. 2010 Oct;51(10):3074-87. Epub 2010 Jul .examined the effect of freeze-and-thaw cycles on 21.Blood sphingolipidomics in healthy humans: impact the stability of sphingolipids in serum and plasma freeze-thawing human plasma either had no effect or Coupling of Proadipocyte Growth and Arrest. http://jcb.rupress.org/content/94/2/394.full.pdf. Aug 1. 1982 storage at -20 C not acceptabel for sex hormones - - 70 C acceptable. Cartenoids drop substatntially at - Sep;15(9):1578-81. Collection, processing, and 20 C after 6 months, up to 97% over 10 yrs; -70 C storage of biological samples in epidemiologic studies: storage stable up to 1`0 yr. Store inflammatory sensitive to F/T - avoid F/T if sex hormones, carotenoids, inflammatory markers, markers or proteomic assay materials <-70 C.
Informa Healthcare - Biomarkers - 16(1):83. http://informahealthcare.com/doi/abs/10.3109/135475 Serum gonadotrophins & steroid homones (FSH, LH, estrone, estradiol, No effects on serum hormone levels of repeated JAMA. 1995;274:1926-1930). Serum Gonadotropins freeze-thaw cycles, up to three cycles were and steroid hormones and the development of ovarian observed (another ref: "decades") estradiol, prolactin, and total testosterone had fairly good performance for both serum and plasma. Cancer Epidemiol Biomarkers Prev. 1995 Jul- Serum-free testosterone increased in time up to 30%, Aug;4(5):509-13. Validity for epidemiological studies of whereas progesterone decreased by about 40% of long-term cryoconservation of steroid and protein Urine hepcidin is more affected by multiple freeze- Clinical Chemistry. 2007; 53(4). Mass spectrometry- thaw cycles and storage . analytical, and biological affected by multiple freeze- based hepcidin measurements in serum and urine: variations that effect serum and urine differently. analytical aspects and clinical implications CT should be analyzed within 2X FT; PGT more Steroids 2001;66:737-41. Stability of salivary steroids: the influences of storage, food, and dental care.
concentrations by ELISA that were significantly lower than those of fresh samples after one freeze-thaw cycle. By ITA the decrease was significant only after two cycles. In specimens frozen at -70 degrees C, Lp(a) concentrations determined by ELISA decreased after two cycles, and by ITA after three freeze-thaw cycles. Serum samples subjected to quick freezing at - 70 degrees C and thawing did not show significant decreases in Lp(a) immunoreactivity during four cycles. Immunoreactivity of Lp(a) in samples stored Clinical Chemistry 38: 1873-1877, 1992; Effect of at 4 degrees C decreased after 6 days but fell faster freezing and thawing of serum on the immunoassay of in serum samples subjected to freezing and thawing lipoprotein(a)Long-Term Fatty Acids Stability in Human Serum Cholesteryl Ester, Triglycerideand Phospholipid Fractions. http://www.jlr.org/content/early/2010/05/06/jlr.D007534 no significant decrease after 10 yr @ -80C .full.pdfHigh Stability of Markers of Cardiovascular Risk in Blood Samples. Clinical Chemistry 49: 652-655, 2003; Approximately 1% of the free PSA was lost per hour of clotting time. Between 2% and 3% of the free PSA was lost per day of storage at 4 degrees C or 23 degrees C. About 0.9% of the free PSA was lost per month of storage at -20 degrees C compared with Urology. 1996 Dec;48(6A Suppl):33-9. Stability of free about 0.4% per month at -70 degrees C. Total PSA prostate-specific antigen in serum samples under a appeared to be stable throughout these studies. free or total PSA, or % free variety of sample collection and sample storage Clin Chim Acta. 2003 Dec;338(1-2):131-4. Effects of stable for up to 3 months when stored at -30 degrees repeated freeze–thawing did storage time on stability of salivary immunoglobulin A not affect s-IgA and albumin and lysozyme.
decline appeared to occur most often between the second and third freeze-thaw cycle. Eight anticardiolipin IgG and three IgM-containing samples Am J Clin Pathol. 1994 Nov;102(5):586-8. Effects of which had been positive initially became negative by repeated freeze-thaw cycles on anticardiolipin antibody immunoreactivity.
Clinical Chemistry 43: 2281-2291, 1997; Development and validation of sensitive method for determination of After >4 years, we have seen no evidence of serum cotinine in smokers and nonsmokers by liquid instability in any of these serum pools during storage chromatography/atmospheric pressure ionization Clinical Chemistry. 1997;43:1570-1576 Comparison of All the urine samples for the biological variability analytical performance and biological variability of studies were stored at <=20 °C until testing.
Both the free and conjugated forms of PYD and DPD have been shown to be stable in urine samples kept at room temperature for several weeks. Several reports show that pyridinium crosslinks can be stored Repeated freeze-thaw cycles at –20°C for years. Similar stability has been reported of urine samples have no for urinary N-terminal (NTX) and C-terminal (CTX) collagen type I telopeptides, while ICTP in serum loses up to 12% of the signal when stored at room temperature for 5 days. The activity of serum tartrate- have a deleterious effect on resistant acid phosphatase (TRAP) declines rapidly serum TRAP activity. BSP cathepsin K (CK), osteocalcin (OC) and during storage at room temperature or even at −20°C levels have been shown to alkaline phosphatase (AP), N-terminal but is stable when stored at −70°C or lower. Serum not change significantly Clin Biochem Rev. 2005 November; 26(4): 97–122. levels of BSP appear rather stable, both at room during repeated freeze-thaw- Biochemical Markers of Bone Turnover Part I: Samples mailed. Aliquots (1 mL) of plasma and serum were stored at –80 °C and transferred on dry ice to collaborating laboratories for analysis within 1 week. For CRP, retinol, and ferritin, changes in concentration during the 96-h storage period were small and not significant (≤10%; P ≥0.1). For folic Clinical Chemistry 51: 230-232, 2005. Whole-Blood acid, the mean concentration changed significantly over time (P = 0.037), with the sharpest decrease Compromising Stability of C-Reactive Protein, Retinol, Ferritin, Folic Acid, and Fatty AcidsJ Clin Lab Anal. 1999;13(4):166-72. Insulin-like growth factors (IGF-I, free IGF-I and IGF-II) and insulin-like Freeze-thaw treatment up to five cycles had little growth factor binding proteins (IGFBP-2, IGFBP-3, impact on plasma levels of IGFs and IGFBP-3.
IGFBP-6, and ALS) in blood circulation.
aliquots stored as plasma or whole blood at 4, 21, or 30 degrees C for 1-5 days and after 1-5 freeze-thaw cycles. stability duration in plasma was 5 days for sVCAM-1 and sICAM-1 and at least 2 days for sE- selectin at 4, 21, and 30 degrees C and 5 days for CRP at 4 and 21 degrees C and 1 day at 30 degrees sICAM-1, sVCAM-1, CRP, C. Stability duration in whole blood was 5 days for and sE-selectin were stable Clin Chem. 2007 Oct;53(10):1858-60. Epub 2007 Aug sVCAM-1 and sICAM-1 and at least 2 days for sE- 3. Stability of soluble adhesion molecules, selectins, selectin at 4, 21, and 30 degrees C and 5 days for sP-selectin is not stable and and C-reactive protein at various temperatures; CRP at 4 and 21 degrees C and 2 days at 30 therefore requires immediate implications for epidemiological and large-scale After completing 10 freeze-thaw cycles, we found no clinically or statistically significant effect on measured Clinical and Diagnostic Laboratory Immunology, antibody levels and found no discernible detrimental January 2003, p. 19-21, Vol. 10, No. 1. Effect of effect on the ability to measure these antibodies by Multiple Freeze-Thaw Cycles on Detection of Measles, Mumps, and Rubella Virus Antibodies One week storage at +4 degrees C did not significantly affect the serum apo E concentration. At -20 degrees C or -80 degrees C no significant change in apo E concentration occurred during up to three months of storage. Moreover, the concentration of apo E was not modified after long-term storage of serum samples kept at -196 degrees C in liquid nitrogen for up to four years. 15 freeze-thaw cycles, over a 3-week period, did not affect the apo E concentration in serum. A similar freeze-thaw procedure applied to purified human recombinant apo E showed that apo E2 isoform was the most 3-week period, did not affect Clin Chem Lab Med. 2000 Jun;38(6):525-8. Effect of apolipoprotein (apo) E concentration in stable in comparison with the apo E3 and apo E4 short- and long-term storage on human serum and recombinant apolipoprotein E concentration.
Samples were stable for up to 10, <1, and at least Clinical Biochemistry, Volume 37, Issue 9, September 100 days for whole blood stored at 4, −20, and −80 2004, Pages 836-839 . Effect of pre-analytical °C. Samples may be kept under refrigeration up to 10 variables on glycohemoglobin measurements in days and at −80 °C if long-term storage is required.
Compared with its initial value, urine albumin, creatinine and UACR all did not show any significant frozen and thawed at least Scand J Clin Lab Invest. 2009;69(8):886-8. Effect of repeated freeze-thaw cycles on urinary albumin-to-creatinine ratio Plasma albumin values were
not affected (P 0.05) by the http://linkinghub.elsevier.com/retrieve/pii/0921448895
first two freeze thaw cycles; 006658
up to 5X (> decreases Ab
WHO/CS/CSR/EDC2001.16 Guidelines for Using HIV Testing Techologies I SurveillanceBioactiva Diagnostica kit insert, http://www.bioactiva.com/resources/RUBM0400BAen HCV TMA exhibited robust performance in detecting HCV RNA in samples subjected to various conditions commonly encountered in a clinical laboratory, including long-term storage, multiple freeze-thaw J Clin Microbiol. 2003 January; 41(1): 310–317. cycles, different collection tubes, and the presence of OK in multiple F/T [Hepatitis Performance Evaluation of the VERSANT HCV RNA endogenous substances, commonly prescribed Qualitative Assay by Using Transcription-Mediated drugs, or other microorganisms and viruses.
samples stored @ -70C gave identical spectra to Molecular & Cellular Proteomics 5.10; 1760-71, 2006. J Biomed Biotech 2010 article ID 906082, 16 pp. Plasma, serum, urine, saliva for protein Store urine & saliva at -80 C. DBS for blood urinary proteome or salivary Challenges for Biomarker Discovery in Body Fluids plasma preferred ver serum; EDTA-plasma pref over Internation Collaboration in Proteomics & Informatics, Clin Adv Hemat Oncol; 4(7): 2006, 541-9. Clinical Proteomics: The Promises and Challenges of Mass Spectrometry-Based Biomarker DiscoveryComb Chem High Throughput Screen. 2005 Dec;8(8):725-33. Prerequisites for peptidomic analysis of blood samples: I. Evaluation of blood specimen plasma vs serum, ULT processing after thrombocytes qualities and determination of technical performance 1% of the proteins changed by 67% after 1 F/T. 2nd, 3rd, 4th, 5th F/T changed a given peak intensity by a median of Cancer Informatics 2005:1, 98-104. Impact of freeze-1.7, 2.4, 3.5, and 3.1 %. 5X thaw cycles and storage time on plasma samples F/T - repeatedly F/T leads to used in mass spectrometry based biomarker platelet-depleted plasma preferable, -80 C good, LN2 storage best, addition of protease inhibitors Proteomics 2005, 5, 3262-77. HUPO Plasma recommended but should be incorporated early & Proteome Project specimen collection & hndling: used judiciously as some form non-specific protein Towards the standardization of paraneters for plasma aducts & others interfere with peptide studies proteome projects.
Expert Review of Proteomics. Review article Plasma/serum proteomics: pre-analytical issues. June plasma & serum proteins for proteomes LiHep plasma used since EDTA produces strong cycles found to be relatively Anal Chem 2006, 78, 4307-18. Impact of analytical signals for for CaEDTA and MgEDTA as well as free small, but keep # F/T to a bias in metabolonomic studies of human blood serum Macromolecules (> 5000 Da, e.g. amino Cancer Informatics 2005:1, 98-104. Impact of freeze- thaw cycles and storage time on plasma samples degradation after sequential used in mass spectrometry based biomarker Storage at 4 °C resulted in altered spectra over a 3-day period reflecting sample degradation. Samples stored at −70 °C, however, gave identical spectra to those from fresh urine samples. Freezing and thawing had little effect on the spectra for up to four freeze-thaw cycles, although evidence of degradation Discovery of Urinary Biomarkers* October 1, 2006 began to be apparent after five freeze-thaw cycles. Molecular & Cellular Proteomics, 5, 1760-1771.
PATH June 2005. RBP-EIA: Collecting, processing, and handling venous capillary, and blood spot very stable in ph1 Acidic conditions, higher concentration in serum than in milk. Milk has more Silence 2010, 1:7, 1-7. microRNA as a new immune- freeze at -80 C until assayed. Most cytokines are stable for up to 2 yr stotage. Degradation of IL-13, IL- However, levels of certain 15, IL-17 & CXCL8 appear within 1 yr of storage, CKs like TNK-α increase with Curr Opin Clin Nutr Metab Care. Digital Commons @ whereas IL-2, IL-4, IL-12, & IL-18 are stable for up to each successive F/T, UConn, 9-1-2010. Conceptual and methodologial 3 yr. IL-1α, IL-1-β, IL-5, IL-6, & IL-10 are degraded issues relevant to cytokine and inflammatory marker up to 50% with 2-3 years of storage.
measurements in clinical research.
Clin Diagn Lab Immunol 1999; 6:89-95. Stability of plasma levels of cytokines and soluble activation measured as stored at ambient to -70 C over 20 markers in patients with human immunoideficiency Only 2 of 15 cytokines remained stable after several F/T cycles. Although most cytokines are stable in a high protein matrix such as LTS showed cytokines are stable for a period up to 2 plasma during the 1st F/T, yr at -80 C. After 4 yr IL-1α, IL-1β, IL-10, IL-15, the second+ F/Ts should be Prerequisites for cytokine measurements in clinical UCPCR remained stable after 7 freeze-thaw cycles but decreased with freezer Clin Chem. 2009 Nov;55(11):2035-9. Epub 2009 Aug UCPCR was unchanged at room temperature for 24 storage time and dropped to 27. Stability and reproducibility of a single-sample h and at 4 degrees C for 72 h even in the absence of 82%-84% of baseline by 90 urinary c-peptide/creatinine ratio and its correlation mulitple product inserts from assay kits for C-peptide Tg small decrease after 3 F/T and a large decrease after 3 months of frozen storage. IL-6 and leptin not affected by F/T (stable α-helical structure), TNF-α increased by 17% after 3 F/T, HGF stable through 4 months of frozen storage, but 23.9% after 6 F/T; HGF Medscape Today discussion, Nov. 9, 2007. Serum thyroglobulin stability for immunoassay: discussion.
BHBA in humans is unaffected by storage temp & J Dairy Sci 2005; 88 (9): 3139-44. Effect of time; NEFA are far less stable. -affected by anticoagulant, storage temperature, and duration of Bovine non-esterified fatty acid & β- anticoagulants, increase with time esp @ higher BHBA did not change after 1 storage on non-esterified fatty acid and B- hydroxybutyrate concentrations from dairy cattle.
When separated serum was stored at + 9 degrees C for seven days, the mean changes in inorganic phosphate and lactate dehydrogenase exceeded significantly (p < 0.05 or 0.001, respectively) the maximum allowable inaccuracy according to the Guidelines of the German Federal Medical Council; all other quantities were sufficiently stable. In serum at room temperature, inorganic phosphate, uric acid, HDL-cholesterol and triacylglycerols increased continuously, whereas bilirubin, LDL-cholesterol, creatine kinase and aspartate aminotransferase decreased more than the guidelines permit during the storage period (p < 0.05 for aspartate aminotransferase, p < 0.001 for the other analytes mentioned). In whole blood stored for 7 days at + 9 cholesterol, HDL- and LDL-cholesterol, degrees C, only the following serum analytes triacylglycerols, creatine kinase, satisfied the stability requirements of the guidelines: calcium, urea, cholesterol, HDL-cholesterol, LDL- cholesterol, triacylglycerols, creatine kinase, gamma- glutamyltransferase and cholinesterase. When stored Eur J Clin Chem Clin Biochem. 1995 Apr;33(4):231-8. at room temperature, only sodium, uric acid, bilirubin, Storage of serum or whole blood samples? Effects of cholesterol, triacylglycerols, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, alpha-amylase and cholinesterase were still stable after 3 days. time and temperature on 22 serum analytes.
The data collected show that all quantities examined are sufficiently stable for fo glucose, urea, creatinine, total proteins, One aliquot was considered as the reference aliquot sodium, potassium, chloride, calcium, and used immediately for the assay of all of the biochemical constituents. All of the other aliquots were stored at −20°C. Three aliquots underwent 1, 2, Repeated freeze-thaw cycles aminotransferase (ALT), creatine kinase or 3 freeze-thaw cycles during a 1- to 3-day period. do not cause changes in the Vet Clin Pathol 35:339-40. Effect of repeated freeze- (CK), and alkaline phosphatase (ALP) The last aliquot remained at −20°C throughout the thaw cycles on routine plasma biochemical study and was thawed on the third day.
F/T process can disruptcellular compartments where Rnases are stored, giving them access to the RNA quality depends on tissue handling prior to RNA RNA. Keep tissue frozen at isolation. This article examines the effect of freeze thaw cycles prior to RNA isolation on RNA http://www.ambion.com/techlib/tn/93/9314.htm Effect of Freeze-Thawing of Tissue on RNA Integrity - Ambion, Inc Never-frozen plasma, freeze-thawed plasma, and thawed plasma left at room temperature for 1 h showed no significant differences in RNA concentration. Plasma RNA is stable in uncentrifuged EDTA blood stored at 4 °C, but to obtain a stable serum RNA concentration, uncentrifuged clotted blood should be stored at 4 °C and processed within observed for freeze-thawed Clin Chem. 2002 Oct;48(10):1647-53. Stability of endogenous and added RNA in blood specimens, serum, and plasma.
Toxicol Appl Pharamcol 2005;206:261-8. Molecular need protease inhibitors for LTS, store in RNAse free epidemiology biomarkers - sample collection and both DNA & RNA must be stored LT @ -80 C, although -20C may be adequate for DNA for up to 5 Profiling of microRNA in blood serum/plasma. Guidelines for the miRCURY LNA™ Universal RT high stability of microRNA in EDTA plasma samples There were no differences in TSH, fT4, TPO-Ab, or TG-Ab concentrations when 50 frozen and thawed serum samples were compared with 50 fresh serum samples. fT3 concentrations were Clin Chem. 2007 Nov;53(11):1986-7. The effect of significantly higher (Student t- freezing, thawing, and short- and long-term storage on TSH, fT4, and fT3 can reliably be analyzed in serum thyrotropin, thyroid hormones, and thyroid Serum Thyrotropin, Thyroid Hormones, samples stored for 23 years at –25 °C, and that TPO- samples but remained within autoantibodies: implications for analyzing samples and Thyroid Autoantibodies Ab and TG-Ab are also stable for 14 years of storage reference intervals.
Choline concentrations with heparin in 5 of 12 volunteers were >10% higher than with EDTA; For freshly collected samples stored at ambient temperature, choline concentrations in all types of samples increased with storage time. For EDTA whole blood, EDTA plasma, and heparin plasma, the choline concentration increased for the first 60 min and then stabilized. For heparin whole blood, the choline concentration continued to increase linearly increases in choline with storage time for >4 h, at which time the choline concentrations in heparin concentrations were increased by approximately Clinical Chemistry. 2008;54:590-593. Choline in Whole Blood and Plasma: Sample Preparation and Stability human transforming growth factor-β1 (TGF--β1) Quantikine human TGF-β1 immunoassay kit insert Samples included in the 12 plates selected for reanalysis for both IGF-I and IGFBP-3 indicated that an additional freeze-thaw cycle did not influence levels of either analyte, confirming previous studies of these assays (19) and suggesting that extended time spent at room temperature may be more Cancer Epidemiol Biomarkers Prev May 2007 16; 1017 . Serum Levels of Insulin-like Growth Factor-I and Insulin-like Growth Factor-I Binding Protein-3: 2X previously F/T samples from NHANES used additional freeze thaw cycle. Quality Control for Studies of Stored Serum routine serum preparation and refrigerated storage of samples for up to 24 hours is acceptable for the measurement of both free and total PSA. Samples that are to be retained for longer than 24 hours Urology 1996; 48(6)S1:33-9. Stability of free prostate- should be frozen. Samples stored for extended specific antigen in serum samples under a variety of sample collection and sample storage conditions Urine samples from 24 h collections were portioned into 50 ml plastic and stored at −80°C until analysis. The endogenous analytes in For freeze-thaw stability, triplicate samples at each concentration for synthetic urine samples and iPF2α-III and 15-epi-iPF2α-III,2,3-dinor- authentic urine samples were subjected to three The Journal of Lipid Research, 2007; 48, 1607-17. complete freeze-thaw cycles with freezing at −20°C thaw, short-term, and long- Quantitation of isoprostane isomers in human urine Repeated freeze-thaw cycles may affect factor level, for example, a reduction in vWF:CB activity and FXII levels. Freeze-thawing may also produce phospholipid The temperature at which archived samples are stored affects their shelf-life. For most coagulation Hemostasis agents (Vitamin K, clotting tests storage at -35°C or less gives a shelf life of several years but storage at -20°C is inadequate.
Practical-Haemostasis.com: a practical guide to laboratory haemostasis more than six cycles of repeated freezing and thawing significantly changed Molecular & Cellular Proteomics 2008; 7: 2061-6. the TIMP-1 concentrations; Banking of Biological Fluids for Studies of Disease- steroids stable to multi-X F/T associated Protein Biomarkers A mean decrease of 2.3% was noted after 72 h storage of whole blood on the bench at room temperature, and a mean decrease of 3.4% after 24 effect on 25(OH)–vitamin D3 h and 8.5% after 7 days storage of serum on the bench in daylight. Mean decreases of 4.5% after 3 days and 8.1% after 7 days storage of serum in the dark at room temperature were noted, whereas a mean decrease of 1.8% was observed after 7-day storage of serum in the refrigerator.A 4.0% decrease concentration was seen Clinical Chemistry. 2009;55:1584-1585. Preanalytical 25(OH)–Vitamin D3 in Human Blood or in the mean concentration was seen following Stability of 25(OH)–Vitamin D3 in Human Blood or storage at –20 °C for up to 2 months.
Serum at Room Temperature: Solid as a Rock Three different patient sample pools were prepared The equivalence of fresh, by serial dilution with Zero Standard, and aliquots individually frozen at –20°C to accommodate multiple sample values over as much testing. Each sample and dilution were assayed in multiple replicates each day over three different assay dates. All data are based on a single freeze- thaw of each aliquot. Additionally, seven serum considerable flexibility in the Clinical Biochemistry 2002; 35(7): 517-21. Analytical samples were subjected to three freeze/thaw cycles logistics of sample and clinical validation of a radioimmunoassay for the Kisspeptin is a peptide product of the KiSS-1 gene and a key regulator of the hypothalamo-pituitary-gonadal axis. Pregnancy is associated with raised plasma kisspeptin concentrations.Kisspeptin-IR was Freeze-thaw cycles did not Endocrine Abstracts (2008) 15 P281. Pre-analytical
poorly preserved in serum samples, but was significantly influence plasma factors affecting measurement of plasma kisspeptin by When Plasma Separating II gel tubes were kept at +4°C or at ambient temperature for up to 24 hours Therapeutic Drug Monitoring:April 2010 - Volume 32 - before centrifugation, ribavirin concentrations Issue 2 - pp 237-241. Stability of Ribavirin Concentrations Depending on the Type of Blood Collection Tube and Preanalytical Conditions F/T significantly increased in Clinical Science 2006, III: 341-7. Influence of pre- proatherogenic mediator. Serum levels higher than platelet rich, but not platelet- analytical and analytical factors on measurement of Cancer biomarkers (a-fetoprotein (AFP) for staging of non-seminomatous testicular cancer and monitoring of hepatocellular carcinoma; cancer antigen-125 (CA-125); and human epididymis protein 4 (HE4) for monitoring of ovarian cancer; thyroglobulin (Tg) for monitoring of thyroid cancer; prostate specific antigen (PSA) for screening and monitoring of clinical samples often used in Medical Laboratory Observer On-line March 2011 of pancreatic cancer; and CA15-3/CA27- a lack of standardization in sample collection, online.com/features/201103/cover_story.aspx ) Cancer processing, and storage has been shown to affect Biomarkers: Surviving the journey from bench to Thawing and refreezing of whole salivary specimens up to 3 times in the pre-analytical period does not Presentation #1045 at ADEA/AADR/CADR Meeting & Aliquot 1 was thawed once prior to analysis, aliquot 2 appreciably affect the Exhibition (March 8-11, 2006). Effects of Repeated was refrozen and thawed twice and aliquot 3 was Freeze-Thaw in Self-collected Salivary Hormone Refrigerate or freeze samples as soon as possible
after collection. Many analytes are not stable at
room temperature, and keeping samples cold after
collection is important. When samples remain at
room temperature for periods of time longer than a
few hours there is also opportunity for bacterial
growth, which can compromise assay validity.(33)
We advocate a conservative approach and advise
that all samples should be maintained at 4ºC for no
longer than several hours before freezing them at or However, freeze-thaw cycles http://www.salimetrics.com/spit-tips/publications/saliva-
below -20ºC (temperature of a regular household
collection-handbook.php. Salimetrics Spit Tips - Saliva serum sample fingerprint based on IgG titers obtained with three different antigens. tested one Epstein-Barr virus (EBV), the Bordetella aliquot after 1 freeze-thaw cycle, one aliquot after 2 samples were tested against Clinical and Vaccine Immunology, May 2010, p. 735-pertussis toxin (PT), and the outer freeze-thaw cycles, and one aliquot after 10 freeze- either pepEBNA1, pepPT, or 740, Vol. 17, No. 5. Immunological Fingerprinting thaw cycles. These aliquots were tested against Method for Differentiation of Serum Samples in pepEBNA1, pepPT, and pepOMP2 in triplicate.
part of the defense mechanism in polymorphonuclear clinical or forensic specimens should always be stored at least in the refrigerator and preferably at −20 °C or lower to avoid any degradation. Finally, results obtained from biosamples that have been stored at room temperature for a longer time should cycles had no significant Analytical and Bioanalytical Chemistry, 388(7), 1505- antiepileptics, cardiovascular drugs, and be interpreted with great care and partial degradation effect on methylphenidate 19. Stability of analytes in biosamples—an important issue in clinical and forensic toxicology? Storage up 72 hr @ 25 C did not affect any analyte. Multi-X F/T led to decreases In: Biomarker's for Early Diagnosis of Alzheimer's P-tau and T-tau stable for up to 4 yrs -20 C LTS. At in Aβ1-42; no decreases for Disease. 2008, Nova Science Pubs. Alzheimer's Disease Biomarkers: From concept to utility.
ASMS 2010 conferemce presentation (http://www.ppdi.com/resource_library/posters/Octreoti [anti-neoplastic agent]stored at -20 C prior to analysis stable up to 5X F/T de_ASMS_2010.pdf ) Assessment effects and http://www.basinc.com/library/presentations/pdf/rsun- stable at least 9 months stored as lysate matrix @ - 05.pdf. Method development & validation of cystine in http://www.xcdtech.com/dioxin2010/pdf/1568.pdf. Pthalates stable multi-X F/T Stability factors influencing the analysis of AFP, hCG and DIA can be reliably determined in sera stored at 4-8°C for days and at -20°C for years. µE3 is not stable in whole blood; samples should be promptly centrifuged in separator tubes or separated from the clot. µE3 is stable in sera stored at 4-8°C for days. In the past, some kits produced systematically different µE3 values after the sera were frozen and thawed. For optimal performance, shipping time should be minimized (e.g., express mail, courier service) and samples should not be exposed to high temperatures. Free beta subunit is not stable in serum when exposed to high temperatures (e.g., daytime summer temperatures in the southern United States), due to dissociation of intact hCG. If free beta is to be measured, samples must be protected from If frozen samples are to be Standards and Guidelines for Clinical Genetics high temperatures (e.g., cool packs with overnight shipment in the summertime). Shipping samples in possible freeze/thaw effects Edition.http://www.acmg.net/Pages/ACMG_Activities/s Prenatal screening for Down Syndrome the form of blood spots can also result in improved [a selective, potent, H1-antihistamine compound indicated for the treatment of allergic rhinitis and Biomirror August 2010. Determination of Levocetrizine chronic idiopathic urticaria] Freezer stability of the in human plasma by liquid chromatography analytes in biomatrix was assessed by analyzing the QC samples stored at –20 ⁰C for at least 30 days. http://www.bmjournal.in/index.php?option=com_conte The stability of analytes in biomatrix following nt&view=article&id=147:determination-of-levocetirizine- repeated three freeze-thaw cycles (stored at –20 C in-human-plasma-by-liquid-chromatography- between cycles) was assessed using QC samples spiked with analytes. Stable at -20 and -70 C.
spectrometry&catid=51:august&Itemid=143 Pharmaceutics 2010; 2: 105-18. Automated [Monoclonal Ab Ca treatment, Tarciva] stable for 24- supported liquid extraction (SLE) coupled with HILIC- hr at ambient temp, and 227 days @ -20 or -70 C.
MS/MS: An appplication to method development and The freeze−thaw stability of paroxetine was determined from spiked human whole [SSRI antidepressant, Paxil ] Replicate (n = 6) 15 µL plasma samples after three human plasma samples at 0.8 and 160 ng/mL were freeze−thaw cycles from −20 spotted onto 226 paper and stored desiccated at room temperature for 35 days. The measured difference of stored samples Anal. Chem., 2011, 83 (1), pp 118–124. Use of Dried concentrations were compared to those of the same compared to fresh samples Plasma Spots in the Determination of samples extracted and analyzed immediately after was −1.6% and 1.4% at 0.8 Pharmacokinetics in Clinical Studies: Validation of a initial spotting and drying. The samples were stable. and 160 ng/mL, respectively. Quantitative Bioanalytical Method Four freeze-thaw cycles had no influence on the analyte http://www.thefreelibrary.com/Immunoluminometric+as say+for+the+midregion+of+pro-atrial+natriuretic.- a0209407126. Immunoluminometric assay for the Mean recovery in eight samples after 6 months of after the first thawing, 100%; midregion of pro-atrial natriuretic peptide in human after the last thawing, 110%). plasmaLimited experiments showed that undiluted serum samples could be thawed and refrozen a few times without any change in analyte concentration. Diluted serum samples also appear to be stable to freeze-thawing. Only sTfR seems to be J. Nutr. 134:3127-3132, November 2004. Combined Measurement of Ferritin, Soluble Transferrin Receptor, Retinol Binding Protein, and C-Reactive Protein by an Inexpensive, Sensitive, and Simple Sandwich Enzyme- Linked Immunosorbent Assay TechniquePresentation at 57th ASMS Conference on Mass Spectrometry. http://www.qps- (Combination medicines used for treatment of HIV.) usa.com/Userfiles/Docs/QPS%202009-016.pdf. LC- Stability of the analytes evaluated at ambient, -20 MS/MS determination of Emtricitabine and Tenofir in and -70 C storage. Stable at all conditions.
human plasmaPresentation at 57th ASMS Conference on Mass Spectrometry. http://www.qps- L-arginine, L-citrulline, and asymmetric usa.com/UserFiles/Docs/Posters%20Abstracts/QPS% 202010-002%20Abstract.pdf Journal of Mass Spectrometry 005; 40(11):1412-16. LC–ESI-MS/MS analysis for the quantification of morphine, codeine, morphine-3-β-D-glucuronide, morphine-6-β-D-glucuronide, and codeine-6-β-D- glucuronide in human urineJ Chromatography B 8, 878 (2010 169-77. Simultaneous dtermination of Tolbutamide, Tolbutamide, omeprazole, midazolam, Analyte stabilty was tested by using QC samples for omeprazole, midazolam, and dextromethorphan in multiple F/T cycles at ambient and -20 C storage. human plasma by LC-MS/MS - A high throughput Stale in -20 C freezer at least 90 days.
approach to evaluate drug-drug interactions.
Six 1,4-benzodiazepines (alprazolam, brompazolam, cloazepam, diazepam, flunitrazepam, lorazepam) in human Stored for 180 days for plasma and urine, 120 days Chiang Mai J Sci 2010; 37(3) 451-63. Stability study of Six 1,4-benzodiazepines in bio-fluids stored at -20 C.
J Chromatography B 857 (2007) 67-75. Steroselective analysis of bupropion and (treatments for depression) Stored at -20 C for 45 hydroxybupropion in human plasma & urine by LC- Effect of freeze and thaw cycles on stability of plasma samples after three freeze (lipid-lowering drug Crestor) Stable at –70 ± 5 °C for and thaw cycles was also J. Braz. Chem. Soc. vol.16 no.5 São Paulo Sept./Oct. 138 days (long term stability) in human plasma. was determined. stable even 2005. Estimation of rosuvastatin in human plasma by Stable over 24.0 hours in human plasma at room HLPC tandem mass spectroscopic method and its application to bioequivalence studyClinical Chermistry and Laboratory Medicine 2008; 46(11):1589-97. Rapid sample preparation and simultaneous quantitation of prostaglandins and lipoxygenase derived fatty acid metabolites by liquid chromatography-mass spectrometry from small (lipid oxidation products important in diabetes) http://www.wwctrials.com/UserFiles/Docs/Levodopa%20&%20Carbidopa_1.2.pdf. Measurement of (Parkinson's Disease treatments) Stable LTS @ -70 levodopa and cardidopa in human plasma by SPE and LC-MS/MS.
The Journal of Lipid Research, 2006; 47, 2340-45. (related to statin treatment of hyperlipidemia) MVA Validation of the LC-MS/MS method for the was found to be stable for up to 28 days of storage quantification of mevalonic acid in human plasma and (a synthetic estrogen antagonist used clinically to treat male and female estrogen receptor-positive breast cancer ) Specimens collected during clinical studies are generally stored frozen at –30 to –80°C freeze/thaw cycles
four cycles of freezing (20 hours at -70°C) and thawing (4 hours at room temperature) induced no discernible loss of Ang-1 immunoreactivity (102% (97% to 107%) versus 100% at baseline) or of Ang-2 immunoreactivity (92% (85% http://ccforum.com/content/12/4/R94. Circulating to 105%) versus 100% at angiopoietin-1 and angiopoietin-2 in critically ill (novel biomarkers of endothelial integrity ) Stability patients: development and clinical application of two only examined for 24 hr at ambient and + 4 C.
To counteract these limitations, several methods have been proposed for determination of total plasma antioxidant capacity (TAC). They can be divided in two main classes: Either distinct antioxidant components are assayed (ex. Vitamin E, ascorbic BMC Clinical Pathology 2002, 2:3. A new automated acid, etc), or the total antioxidant potency is method for the determination of the Total Antioxidant estimated by the combined reducing activities of a during three freeze thawing Capacity (TAC) of human plasma, based on the crocin total plasma antioxidant capacity (TAC) given body fluid (especially plasma) bleaching assay [cocin is a carotenoid] Determination of Naloxone and Nornaloxone (Noroxymorphone) by High-Performance Liquid Analytes were stable in plasma and urine for up to 24 Chromatography–Electrospray Ionization-Tandem h at room temperature and in plasma after three powder forms mixed with DMSO & stored in sealed microtiter plates under Ar2. LC-MS assay after every never Th. No degradation - J Biomole Scrn 8(2), 200321-5. The effect of freeze- 5th F/T cycle, plus ambient and never Th controls thaw cycles on the stability of compounds in DMSO

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