Diagnostic Accuracy of Smartphone-Enabled Urinary Albumin-to-Creatinine Ratio Testing

Area of Science:

• Nephrology
• Clinical Diagnostics
• Biomarker Analysis

Background:

• Albuminuria is a critical biomarker for chronic kidney disease (CKD) detection, especially in at-risk populations.
• Home-use diagnostic tests, like the FDA-cleared Minuteful Kidney Test (MKT), are emerging for semiquantitative albuminuria assessment.
• Evaluating new diagnostic tools against established laboratory methods is crucial for clinical adoption.

Purpose of the Study:

• To compare the diagnostic accuracy of the Minuteful Kidney Test (MKT) against a standard laboratory quantitative method (Beckman Coulter AU 480 analyzer).
• To assess the MKT's ability to detect albuminuria in individuals with or at risk for CKD.
• To evaluate the MKT's performance based on KDIGO albuminuria classification categories.

Main Methods:

• Urine samples from individuals with kidney damage risk factors were analyzed using both MKT and a standard laboratory method for urinary albumin-to-creatinine ratio (uACR).
• Albuminuria was categorized using KDIGO guidelines (A1, A2, A3).
• Diagnostic accuracy metrics, including sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), were calculated for the MKT.

Main Results:

• The MKT demonstrated high sensitivity (96.4%) and negative predictive value (98.6%) for detecting albuminuria (uACR >30 mg/g).
• The test achieved a specificity of 84.2% and a positive predictive value of 66.8%.
• MKT accurately categorized 85.6% of samples into KDIGO albuminuria stages and correctly identified all severely increased albuminuria (A3) samples.

Conclusions:

• The Minuteful Kidney Test (MKT) exhibits high sensitivity, surpassing guideline thresholds, and acceptable specificity for albuminuria detection in high-risk populations.
• The MKT has the potential to enhance CKD detection and management, particularly in primary care and community settings.
• The test's accurate rule-out capability is valuable for early intervention strategies in kidney disease management.