[Challenge and limitations in determination of serum creatinine]

Area of Science:

• Clinical Chemistry
• Nephrology
• Biomarker Analysis

Background:

• Clinical guidelines since 2006 recommend serum creatinine for early chronic kidney disease (CKD) detection.
• Limitations in creatinine assay specificity, particularly the Jaffe method, necessitate harmonization for comparable results.
• Advancements include enzymatic, compensated-Jaffe, and chromatographic methods offering higher accuracy.

Purpose of the Study:

• To compare the diagnostic value and limitations of various creatinine measurement methods.
• To address the uncertainty in estimated glomerular filtration rate (eGFR) and CKD staging due to new creatinine assays.
• To evaluate the impact of method-specific creatinine values on established eGFR formulas.

Main Methods:

• Review and comparison of different creatinine determination assays (Jaffe, enzymatic, compensated-Jaffe, HPLC).
• Analysis of the effect of lower creatinine values from newer methods on established eGFR calculation formulas (MDRD-186, Cockcroft-Gault, Quadratic).
• Evaluation of updated eGFR formulas (MDRD-175) recommended for creatinine methods traceable to isotope-dilution mass spectrometry.

Main Results:

• Newer creatinine assays (enzymatic, compensated-Jaffe, HPLC) provide more accurate but lower creatinine values compared to the Jaffe method.
• Applying new creatinine results to older eGFR formulas leads to overestimation of glomerular filtration rate.
• This discrepancy creates uncertainty in CKD staging and diagnosis.

Conclusions:

• The shift to more accurate creatinine assays necessitates the use of updated eGFR formulas for reliable CKD detection and staging.
• The Modification of Diet in Renal Disease-175 formula is advised for creatinine methods traceable to isotope-dilution mass spectrometry.
• Accurate creatinine measurement and appropriate eGFR calculation are crucial for effective chronic kidney disease management.