Fingernail creatinine as a predictor of prior renal function

Area of Science:

• Nephrology
• Biochemistry
• Clinical Diagnostics

Background:

• Differentiating acute kidney injury from chronic kidney disease is clinically challenging.
• Serum creatinine is a common marker for kidney function, but its interpretation can be complex in certain patient groups.
• Novel biomarkers are needed to provide historical context for renal function.

Purpose of the Study:

• To investigate the utility of fingernail creatinine as a biomarker to differentiate acute from chronic renal failure.
• To assess the correlation between fingernail and serum creatinine levels over time in various patient populations.

Main Methods:

• Fingernail and serum creatinine levels were measured in healthy adults, patients with acute kidney injury, chronic kidney disease, on hemodialysis, and kidney transplant recipients.
• Fingernail creatinine was compared to concurrent and past serum creatinine values (up to 1 month prior).
• Correlations were analyzed in maintenance hemodialysis patients and changes were tracked post-renal transplantation.

Main Results:

• Fingernail creatinine was significantly elevated in chronic kidney disease, hemodialysis patients, and early post-transplant recipients.
• Fingernail creatinine levels were not significantly different from normal in acute kidney injury or late post-transplant recipients.
• A strong correlation was observed between fingernail creatinine and serum creatinine from approximately 9 months prior in hemodialysis patients.
• Fingernail creatinine normalized within 90-120 days after kidney transplantation.

Conclusions:

• Fingernail creatinine may serve as a valuable tool to assess historical kidney function, distinguishing recent-onset from long-standing renal failure.
• This biomarker could offer insights into past serum creatinine levels, aiding clinical diagnosis and management.
• Further research is warranted to establish clinical guidelines for fingernail creatinine utilization.