IntroductionAlbuminuria is commonly used to predict the onset and to follow the progression of diabetic nephropathy (DN), but it lacks both sensitivity and specificity in early stages.AimWe assessed urinary cyclophilin A (CypA) as a biomarker for the diagnosis of DN in Egyptian patients with type 2 diabetes.Patients and methodsThe study was conducted on 150 Egyptian participants aged 30–65 years; 125 (58 male individuals and 67 female individuals) patients with type 2 diabetes mellitus (diabetes duration>5 years) in different stages of DN and 25 age-matched and sex-matched healthy control participants comprised the study cohort. Estimated glomerular filtration rate and urine albumin/creatinine ratio (ACR) were assessed in all participants. Urinary CypA was measured in the morning specimen.ResultsUrinary CypA was significantly higher in patients with stage 2 DN, as compared with stage 1 patients (P=0.02) and the control group (P=0.017), with no significant change in urine ACR between stages 1 and 2 (P=0.809). Urinary CypA also showed a steady rise in DN stages 3, 4 and 5 (P<0.001). Urinary CypA had strong positive correlations with creatinine and urine ACR and a strong negative correlation with estimated glomerular filtration rate in patients with DN (P<0.001 for all).ConclusionWe suggest that urinary CypA is a good biomarker for early detection of DN in patients with type 2 diabetes. It starts to rise before urine ACR. It also correlates well with the progression of DN. A larger study is needed to confirm its superiority over urine ACR in the early stages of DN.