Adding calcium to EDTA plasma samples prior to analysis could solve the compatibility issue in commercially available ELISAs that are standardized for serum.

Author(s): Tenland E, Hillman M

Publication: Clin Chem Lab Med, 2013, Vol. 51, Page e145-7

PubMed ID: 23314548 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 analyzing EDTA plasma rather than serum and adding CaCl2 to EDTA plasma on results of the quantikine human sCD163 ELISA. The manufacturer recommends against the use of EDTA plasma in this ELISA but claims that it is suitable for use with serum and heparin plasma. Specimens were obtained from 49 diabetic patients and serum and plasma were stored at -20 degrees C until analysis. An aliquot of EDTA plasma was thawed and incubated with CaCl2 overnight at 4 degrees C.

   Summary of Findings:

   While the majority of EDTA plasma specimens assayed by the sCD163 ELISA performed similarly to serum, some EDTA plasma specimens gave significantly higher sCD163 measurements than their serum counterparts. Overnight incubation of EDTA plasma with CaCl2 was able to attenuate the falsely high results so that there was no effective bias between the plasma and corresponding serum specimens.

   Biospecimens

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

   Preservative Types

   • Frozen

   Diagnoses:

   • Diabetes Type 1
   • Diabetes Type 2

   Platform:

   Analyte	Technology Platform
   Protein	ELISA

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Biospecimen Aliquots and Components	Blood and blood products	Plasma Serum
   Biospecimen Acquisition	Anticoagulant	EDTA None
   Biospecimen Aliquots and Components	Biospecimen components	25 mM CaCl2 No added CaCl2

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