Impact of analytical bias in metabonomic studies of human blood serum and plasma.

Author(s): Teahan O, Gamble S, Holmes E, Waxman J, Nicholson JK, Bevan C, Keun HC

Publication: Anal Chem, 2006, Vol. 78, Page 4307-18

PubMed ID: 16808437 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to determine the effects of clotting time and temperature, freeze-thaw cycling, use of plasma instead of serum and delayed analysis on NMR spectra. After experimental storage, plasma and serum specimens were stored at -80 degrees C until analysis.

   Summary of Findings:

   More than 50% of the variation in NMR spectra in serum was attributed to differences between the 4 patients. Clotting time increased the peaks associated with lactate, but this was attenuated when clotting was performed on ice rather than at room temperature. Only small differences in spectra were observed between heparinated plasma and serum specimens, and these were predominantly attributed to lipids. Further, small differences in average peak height were observed after serum from 24 individuals was subjected to an additional freeze-thaw cycle, but they were 2 orders of magnitude less than the average peak height and were predominantly due to changes in high molecular weight species. When 1 sample was stored in the NMR machine prior to analysis, a less than 5% variation in spectra was observed over the course of 3 h, but the authors state the variations in lipids that occurred might cause a systematic bias if analysis is delayed.

   Biospecimens

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

   Preservative Types

   • None (Fresh)

   Diagnoses:

   • Not specified

   Platform:

   Analyte	Technology Platform
   Carbohydrate	NMR
   Lipid	NMR
   Small molecule	NMR
   Steroid	NMR

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Storage	Storage duration	30 min 60 min 120 min 180 min
   Storage	Storage temperature	On ice Room temperature
   Biospecimen Aliquots and Components	Blood and blood products	Plasma Serum
   Storage	Freeze/thaw cycling	1 cycle 2 cycles
   Biospecimen Aliquots and Components	Centrifugation	Centrifugation delays investigated

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