Jaffe reaction

Jaffe Reaction

The Jaffe reaction is a well-known biochemical method used for the quantitative determination of creatinine levels in urine and serum. Named after the German chemist Max Jaffe, this reaction has been widely used in clinical chemistry since its discovery in the late 19th century.

Principle

The Jaffe reaction is based on the principle that creatinine reacts with picric acid under alkaline conditions to form a red-orange complex. The intensity of the color produced is directly proportional to the concentration of creatinine present in the sample. This colorimetric method is used to measure the absorbance of the complex at a specific wavelength, typically 520 nm, using a spectrophotometer.

Procedure

The procedure of the Jaffe reaction involves the addition of an alkaline picrate solution to the sample containing creatinine. The mixture is then incubated at room temperature for a specific period, usually about 20 minutes. After incubation, the absorbance of the solution is measured using a spectrophotometer. The concentration of creatinine is then calculated from the absorbance using a standard curve.

Interferences

Despite its widespread use, the Jaffe reaction is known to have several potential interferences. Non-creatinine chromogens, such as glucose, ketones, and certain drugs, can react with picric acid to produce a color, leading to an overestimation of creatinine levels. Modern modifications of the Jaffe method have been developed to minimize these interferences.

Clinical Significance

The Jaffe reaction is primarily used in the diagnosis and monitoring of renal disease. Elevated creatinine levels, as determined by the Jaffe reaction, can indicate impaired kidney function. It is also used in the calculation of the glomerular filtration rate (GFR), a key indicator of kidney function.

See Also

• Creatinine
• Picric acid
• Spectrophotometry
• Renal function