ORIGINAL ARTICLE   

Minerva Biotechnology and Biomolecular Research 2021 March;33(1):6-11

DOI: 10.23736/S2724-542X.20.02710-X

Copyright © 2020 EDIZIONI MINERVA MEDICA

lingua: Inglese

Analytical and clinical comparison between two different chemiluminescent enzyme immunoassays for the measurement of C-peptide in serum

Gian P. CAVIGLIA ¹, Chiara ROSSO ¹ ✉, Angelo ARMANDI ¹, Davide G. RIBALDONE ^{1, 2}, Rinaldo PELLICANO ^{1, 2}, Elisabetta BUGIANESI ^{1, 2}

¹ Department of Medical Sciences, University of Turin, Turin, Italy; ² Division of Gastroenterology, Department of General and Specialist Medicine, Molinette Hospital, Città della Salute e della Scienza, Turin, Italy

BACKGROUND: Connecting peptide (C-peptide) is the cleavage product of proinsulin and is released in blood in equimolar amounts to insulin. Compared to the latter, C-peptide has a longer plasma half-life and is less affected by hemolysis, therefore could be a useful marker of insulin production. We aimed to compare the analytical performance of two different chemiluminescent enzyme immunoassays (CLEIA) for the measurement of C-peptide in serum.
METHODS: Overall, 106 subjects (median age: 51 [20-75]; M/F: 72/34) with available serum samples were included in the study; 14 (13.2%) had a diagnosis of impaired fasting glucose (IFG) and 28 (26.4%) of type 2 diabetes mellitus (T2DM). C-peptide was measured in serum by Elecsys^® C-peptide (Roche, Mannheim, Germany) and by Lumipulse^® c-Peptide (Fujirebio, Tokyo, Japan) CLEIAs.
RESULTS: Median C-peptide levels measured by Elecsys^® and Lumipulse^® were comparable in our study cohort (2.6 [0.3-13.3] ng/mL vs. 2.54 (0.01-10.50) ng/mL, respectively; P=0.665). No random differences were observed between the two methods; the analytical agreement between both was satisfactory. C-peptide serum values were strongly correlated to insulin concentration (rs=0.626, P<0.001, for Elecsys^®; rs=0.719, P<0.001, for Lumipulse^®) and increased in a stepwise manner from patients with normal glucose tolerance to those with IFG and T2DM (P<0.001). Both CLEIAs showed an area under the curve >0.7 for the discrimination between patients with and without overt T2DM.
CONCLUSIONS: The Elecsys^® and Lumipulse^® C-peptide CLEIAs showed an adequate analytical agreement. The measurement of serum C-peptide may represent a valid surrogate of pancreatic β-cell function with a potential useful application in the clinical setting.

KEY WORDS: C-peptide; Glucose; Diabetes mellitus, type 2