Cystatin C and creatinine eGFR reference intervals in healthy adults from Cameroon.

Several equations are available for estimation of glomerular filtration rates (eGFRs) from serum cystatin C and creatinine, but data on reference intervals from healthy subjects are scarce. Employing nine well-known equations, we calculated eGFRs for healthy Cameroonians, 194 men and 187 women 18-71 years of age. Reference intervals were calculated using conventional techniques. For subjects < 50 years of age the eGFR reference intervals were with CAPA (men; women) 70.1-127.1; 79.9-172.2, with CKD-EPIcys 2012 75.1-131.2; 81.3-135.5, with LM rev 65.4-106.5; 61.4-110.3, with CKD-EPIcrea 2021 74.1-127.2; 67.0-129.8, with mean (LM rev, CAPA) 72.2-110.6; 72.8-136.9, with CKD-EPIcrea, cys 2021 81.1-126.6; 77.0-135.7, with EKFCcys 85.5-116.3; 83.3-124.8, with EKFCcrea 69.4-114.2; 62.8-114.3, and with EKFCcrea, cys 82.5-114.0: 77.1-116.4 mL/min/1.73 m2, respectively. Median eGFRcys was significantly higher than eGFRcrea irrespective of equations used. The eGFRcys difference between healthy men and women aged < 50 years may be explained by lower production rates of cystatin C in women. The higher eGFRcys reference intervals compared to that of eGFRcrea may be caused by increased tubular secretion of creatinine or increased production of cystatin C in the cohorts used for establishing the equations relative the case in healthy subjects. This suggests that the eGFR equations need to be further assessed regarding accuracy to adequately correspond to true GFR.