Accuracy of Point-of-Care Transdermal GFR Methodology.

Area of Science:

• Nephrology
• Medical Diagnostics
• Biomedical Engineering

Background:

• Chronic kidney disease (CKD) staging relies on estimated glomerular filtration rate (eGFR) equations, which can lack individual patient accuracy.
• Current plasma-derived GFR methods are accurate but clinically impractical due to multiple blood draws and lab analysis.
• Accurate GFR assessment is crucial for timely CKD diagnosis and management.

Purpose of the Study:

• To evaluate the accuracy of transdermal GFR (tGFR) using the fluorescent tracer relmapirazin.
• To compare tGFR with plasma-derived indexed GFR (nGFR) in a diverse patient cohort.
• To assess tGFR performance across different CKD stages and Fitzpatrick Skin Scale (FSS) types.

Main Methods:

• A multicenter pivotal clinical study involving 182 participants with eGFR ranging from normal to CKD stage 4.
• Participants received intravenous administration of relmapirazin, a fluorescent GFR tracer agent.
• A chest-worn sensor detected transdermal fluorescence for real-time GFR assessment (tGFR).

Main Results:

• The overall cohort achieved a P30 (percentage of tGFR values within 30% of nGFR) of 94%.
• High accuracy was maintained across different GFR levels (>60 ml/min/1.73 m²: 96%; <60 ml/min/1.73 m²: 92%).
• Excellent performance was observed across all Fitzpatrick Skin Scale types (I-III: 96%; IV-VI: 90%).

Conclusions:

• Transdermal GFR (tGFR) using relmapirazin demonstrates superior accuracy compared to creatinine-based eGFR equations.
• The tGFR method provides accurate kidney function assessment across all human skin colors and CKD stages.
• tGFR represents a promising, clinically practical, point-of-care tool for GFR measurement.