Conference abstract

When there is no hemolysis, Plasma C-peptide levels are stable up to 5 days at 4°C

Pan African Medical Journal - Conference Proceedings. 2019:11(3).09 Dec 2019.
doi: 10.11604/pamj-cp.2019.11.3.982

Contact the corresponding author
Keywords: C-peptide, heamolysis, diabetes
Oral presentation

When there is no hemolysis, Plasma C-peptide levels are stable up to 5 days at 4°C

Anxious Jackson Niwaha1,2, Wisdom Nakanga1,2, Jean-Claude Katte1, Beverley Shields1, Angus Jones1, Timothy McDonald1,&, Andrew Tym Hattersley1

1College of Health and Medicine, University of Exeter Medical School, Exeter, United Kingdom, 2MRC/UVRI/LSHTM Research Unit, Entebbe, Uganda

&Corresponding author
Timothy McDonald, College of Health and Medicine, University of Exeter Medical School, Exeter, United Kingdom

Abstract

Introduction: C-peptide is the best measure of endogenous insulin secretion and has become crucial in the clinical management of diabetes in most countries. Until now, there is minimal evidence regarding effect of hemolysis on the stability of C-peptide on and off cells in different storage conditions. In this study, we investigated the impact of mild-moderate and severe/high hemolysis on the stability of plasma and serum C-peptide on and off cells, stored at room temperature or 4°C.

Methods: we collected a total of 36 plasma and 36 serum samples. To cause low (mild-moderate) hemolysis, we froze the samples for 8 minutes and 13 minutes for high (severe) hemolysis to match their respective hemolysis indices. We investigated the impact of hemolysis, preservative type, storage conditions and duration of storage on the stability of C-peptide.

Results: without hemolysis, Plasma C-peptide (EDTA) was stable up to 5 days when stored at 4°C; but reduced by 10% on day 2 when stored at room temperature. For serum, C-pepide remained stable at approximately 98% of the baseline in the samples stored at 4°C (off and on cells) for 2 days. At room temperature, the serum C-peptide levels reduced to 80% of the baseline. With mild-moderate hemolysis, Plasma C-peptide remained stable at 4°C up to days 3 (off cells) and 2 (on cells); at room temperature it declined to 90% (off cells) and 70% of baseline (on cells) at day 1. Severe hemolysis markedly reduced the stability of C-peptide in both serum and plasma analytes.

Conclusion: generally, hemolysis reduces C-peptide stability. In settings where analysis is not done in real-time, C-peptide, if collected in plasma (EDTA) tubes and kept at 4°C can be accurately tested within 5 days or 3 days of sample collection if there is no hemolysis and mild-moderate hemolysis respectively.