Frontiers in Medical Technology · Oct 29, 2026
Urinary creatinine estimation as an important analytical limitation of semi-quantitative albumin-to-creatinine ratio strip testing: a diagnostic accuracy study
By Bunpo P, Nanthawong P, Chomphusri C et al.
Background: Albuminuria is a key biomarker for chronic kidney disease and cardiovascular risk. Point-of-care urine albumin-to-creatinine ratio (UACR) testing may improve access to chronic kidney disease screening. However, limited evidence is available regarding the agreement of the individual albumin and creatinine components of semi-quantitative UACR strip tests with quantitative laboratory measurements. Methods: We evaluated 400 spot urine specimens using the Dirui H13-Cr semi-quantitative UACR strip and compared results with quantitative immunoturbidimetric UACR measurement performed on a Roche Cobas c503 analyzer. Agreement was assessed using Cohen's kappa coefficients, including category-specific agreement according to the KDIGO A1, A2, A3 albuminuria categories, and diagnostic performance was evaluated using sensitivity, specificity, predictive values, likelihood ratios, and diagnostic odds ratio (DOR). Results: Agreement between strip-based and quantitative measurements was substantial for urinary albumin ( κ =0.691; 95% CI, 0.632–0.751) but considerably lower for urinary creatinine ( κ =0.377; 95% CI, 0.331–0.423). Despite this disparity, UACR classification demonstrated substantial agreement ( κ =0.627; 95% CI, 0.541–0.714). The findings suggest that semi-quantitative creatinine estimation is the primary analytical determinant of UACR misclassification. For detection of abnormal albuminuria (UACR ≥30 mg/g), the strip achieved a sensitivity of 83.66% and specificity of 83.22%. The PPV was 89.96% and NPV was 73.91%. Category-specific analysis showed that 131 of 177 A2 specimens (74.0%) were classified as A2 by the strip, whereas 64 of 80 A3 specimens (80.0%) were classified as A2 rather than A3. Conclusion: The Dirui H13-Cr strip demonstrated acceptable performance for albuminuria screening. However, semi-quantitative urinary creatinine estimation represented an important analytical limitation affecting UACR classification accuracy. Future development of strip-based UACR technologies should prioritize improved creatinine measurement to enhance diagnostic performance.