In the Jaffe reaction, creatinine reacts with picric acid to form a colored complex. This forms the basis for the commonest methods for measuring serum creatinine. However, this test has well known limitations. Under normal circumstances, the Jaffe reaction overestimates the serum creatinine concentration by 10-20% because of the presence of endogenous chromogens. These chromogens include acetone and acetoacetate which, in the case of diabetic ketoacidosis, can lead to a significant overestimation of the serum creatinine. Similarly, certain drugs, including cephalosporins, flucytosine and barbiturates, can interfere with the assay.
I'm Dr. Joshua Schwimmer, a nephrologist and internal medicine physician in New York City. • Kidney Notes was the first active nephrology blog. (Trivia: Kidney Notes is so old that the National Library of Medicine still uses it as an example of how to formally cite blogs.) • Professionally, you can find me at Kidney.nyc. • Kidney Notes is for educational purposes only, not medical advice. Consult qualified health care professionals. See disclaimer.
Wednesday, June 2, 2010
Pseudohypercreatininemia
Via the Renal Fellow Network: