Which method is typically used to analyze creatinine (CREA) in laboratory tests?

• A. Jaffe reaction with picric acid oxidation and spectrophotometric readout
• B. Enzymatic lactate dehydrogenase assay
• C. Immunoassay using monoclonal antibodies
• D. Gas chromatography-mass spectrometry

Answer: (A)

Creatinine in clinical labs is typically analyzed using the Jaffe reaction, where creatinine reacts with picric acid in alkaline conditions to form a colored complex whose intensity is measured spectrophotometrically. This approach is favored for routine testing because it’s simple, inexpensive, and compatible with automated analyzers, providing a practical estimate of kidney function. Be aware that various substances can interfere with the reaction, so laboratories may use compensated or kinetic variants to improve specificity or, in some settings, switch to enzymatic creatinine assays. The other methods—enzymatic assays, immunoassays with monoclonal antibodies, or gas chromatography–mass spectrometry—are not the standard routine choices for creatinine measurement due to issues like cost, complexity, or limited throughput in everyday clinical testing.