Targeted metabolomics identifies reliable and stable metabolites in human serum and plasma samples.

Author(s): Breier M, Wahl S, Prehn C, Fugmann M, Ferrari U, Weise M, Banning F, Seissler J, Grallert H, Adamski J, Lechner A

Publication: PLoS One, 2014, Vol. 9, Page e89728

PubMed ID: 24586991 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to compare the stability of 188 plasma and 159 serum metabolites during storage and to investigate the effects of freeze-thaw cycling and collection tube type on levels of 159 metabolites in serum. Plasma and serum were obtained from 20 healthy fasting patients on three different days. Plasma was collected into K+EDTA monovettes and stored for 0 min, 3 h, 6 h or 24 h at 4 degrees C, or 24 h at room temperature, before centrifugation. Serum was collected into monovettes with clot activator and centrifuged after 30 min or in monovettes with a gel separator and a clot activator and centrifuged after 30 min, 3 h, 6 h, or 24 h at 4 degrees C. Both plasma and serum were aliquoted and stored at -80 degrees C until analysis.

   Summary of Findings:

   The median within-person coefficients of variance (WCV) were similar for serum and plasma, but the between person CVs (BCV) and interclass coefficient correlations (ICC) were slightly higher in serum specimens than plasma specimens. While 101 metabolite concentrations were significantly higher in serum than plasma, only levels of sarcosine were significantly lower in serum than plasma. Storage of plasma for up to 24 h at 4 degrees C significantly affected the levels of 14 metabolites (p<0.01) with 5 showing significant changes after as little as 3 h at 4 degrees C. 44 metabolites were affected by storage of plasma at room temperature for 24 h, of which, 33 had increased levels compared to 0 h (p<0.05). All of the metabolites affected by storage of plasma at 4 degrees C were also significantly affected by storage of plasma at room temperature. Generally, the compound class of amino acids was the least stable during plasma storage, and the sphingolipids were the most stable, with no changes found, even after 24 h at room temperature. 19 metabolites were affected by storage of serum at 4 degrees C for up to 24 h. When blood was collected into tubes containing a gel barrier, methionine sulfoxide levels were higher than when serum was collected in tubes containing clot activator only, but no other metabolites were significantly affected by the presence of gel-barrier. Similarly, only methionine sulfoxide was affected by a single serum freeze-thaw cycle, and only 11 of the 159 metabolites tested in serum were affected by 2 freeze-thaw cycles. The authors report that neither gender nor last meal before fasting had effects on metabolite concentrations, but data was not shown.

   Biospecimens

   • Bodily Fluid - Blood
   • Bodily Fluid - Serum
   • Bodily Fluid - Plasma

   Preservative Types

   • Frozen

   Diagnoses:

   • Normal

   Platform:

   Analyte	Technology Platform
   Peptide	LC-ESI-MS/MS
   Small molecule	LC-ESI-MS/MS

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Preaquisition	Patient gender	Female Male
   Storage	Storage duration	0 min 30 min 3 h 6 h 24 h
   Storage	Storage temperature	4 degrees C Room temperature
   Storage	Freeze/thaw cycling	0 cycles 1 cycle 2 cycles
   Biospecimen Aliquots and Components	Blood and blood products	Plasma Serum Whole blood
   Biospecimen Acquisition	Type of collection container/solution	Serum clot activator Serum gel-barrier with clot activator
   Preaquisition	Patient diet	Unspecified last meal before fast
   Biospecimen Aliquots and Components	Centrifugation	Centrifugation delays investigated

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