The Reference Intervals for Serum C-Terminal Agrin Fragment in Healthy Individuals and as a Biomarker for Renal Function in Kidney Transplant Recipients

Abstract

Background: C-terminal agrin fragment (CAF) has been shown to be a promising new biomarker for kidney function. The aim of this study was to verify the reference intervals for CAF in Chinese healthy adults and to assess the efficiency of CAF for monitoring renal function after transplantation. Methods: Serum samples were collected from 200 healthy adult subjects and 60 living donor kidney recipients before and on day 1, day 2 and at 6 months after transplantation. We measured serum CAF, creatinine, cystatin C and NGAL concentrations at each time. Estimated glomerular filtration rate (eGFR) was evaluated by Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Reference intervals for CAF were determined at 2.5th and 97.5th percentiles. Results: Serum CAF concentrations were observed to be higher in females of old age groups while no significant differences were discovered in males between age groups. There were significant gender-related differences in CAF in old age groups (50–64 and ≥65 years). Serum CAF correlated positively with serum creatinine, cystatin C and negatively with eGFR on day 1, day 2 and at 6 months after kidney transplantation. CAF and NGAL fell rapidly into the normal range on the second postoperative day, prior to creatinine and cystatin C. Conclusions: This study verified the reference intervals for serum CAF. CAF could be a potential new biomarker for kidney function monitoring.