Urine Test Strips Show Promise for Kidney Disease Screening

TOPLINE:

Urine test strip analysis emerged as a valuable screening tool for chronic kidney disease (CKD) in low-risk individuals, with the albumin-to-creatinine ratio (ACR) showing higher sensitivity and specificity for detecting albuminuria than the protein-to-creatinine ratio (PCR).

METHODOLOGY:

• Researchers conducted a study with cross-sectional (n = 940) and validation (n = 927) patient cohorts to evaluate the effectiveness of the ACR and PCR in screening for CKD.
• Mid-stream urine specimens were collected in sterile containers and analysed within 4 hours of arrival at the laboratory.
• A fully automated urine test strip analyser (UC-3500, Sysmex) was used to semi-quantitatively measure the urinary protein, albumin, and creatinine levels.
• The diagnostic performances of the semi-quantitative ACR and PCR tests were compared with those of quantitative lab-based ACR and PCR tests in individuals from the cross-sectional cohort.
• The main goal of the validation cohort was to assess the effectiveness of urine test strip readings for albuminuria and proteinuria as screening tools in an outpatient population without a known diagnosis of CKD.

TAKEAWAY:

• In the cross-sectional cohort, the semi-quantitative ACR had a sensitivity of 78.1% and a specificity of 93.3% at a 30 mg/g creatinine cutoff, with over 90% overall agreement with quantitative ACR results.
• In the validation cohort, the semi-quantitative ACR showed improved sensitivity (89.9%) and specificity (92.1%), and the semi-quantitative PCR had a sensitivity of 69.8% and specificity of 93.8%.
• The semi-quantitative ACR had a positive likelihood ratio of 11.3 and a negative likelihood ratio of 0.11, indicating strong predictive capability for CKD. In contrast, the semi-quantitative PCR and qualitative protein concentration showed lower predictive performance.
• The semi-quantitative ACR had the highest predictive accuracy for CKD (area under the curve [AUC], 0.933), significantly outperforming the semi-quantitative PCR (AUC, 0.830) and qualitative protein concentration (AUC, 0.774).

IN PRACTICE:

“Our data further add to the evidence that urine test strips may be a valuable screening tool for CKD in low-risk individuals. Moreover, if urine test strips are used to screen for albuminuria and CKD, ACR-readout is preferred as a decision criterion for reflex testing,” the authors wrote.

SOURCE:

The study was led by Stijn Lambrecht, Ghent University Hospital, Ghent, Belgium, and was published online on March 10, 2025, in BMC Nephrology.

LIMITATIONS:

The CKD stage determined on the basis of semi-quantitative test strip results may require validation through quantitative analysis.

DISCLOSURES:

This study did not receive any specific funding. The authors declared no competing interests.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.