The Jaffe reaction, named for 19th century German biochemist Max Jaffe, is a colorometric assay used by most every clinical lab to measure creatinine. In an alkaline medium, creatinine reacts with picric acid to form a red colored compound; the amount of color change is proportional to the level of creatinine. Increases in creatinine make the final solution more red, but a number of other endogenously produced molecules interfere with the assay and make the color of the solution more red.

Ketones. Ever notice an unusually large number of DKA patients with AKI’s? Both acetone and acetoacetate falsely elevate lab measurement of serum creatinine.

Cephalosporins. Many are chromogens which falsely increase the redness of the Jaffe reaction, and result  in falsely elevated serum creatinine values

Intralipid. This is not news. Lab values in patients after intralipid administration are notoriously unreliable. Serum creatinine values are falsely lower during severe lipemia.

References:

Calmarza, Pilar, and José Cordero. “Lipemia interferences in routine clinical biochemical tests.” Biochemia medica: Biochemia medica 21.2 (2011): 160-166.

Samra, Manpreet, and Antoine C. Abcar. “False estimates of elevated creatinine.” The Permanente Journal 16.2 (2012): 51.