17 Are All Creatinine Results Suspect During Dopamine and Dobutamine Infusions?

Dopamine and dobutamine infusions administrated in critical care patients with heart failure or septic shock have been shown to interfere in enzymatic creatinine assays that use peroxidase reaction causing falsely decreased creatinine values. The frequency of the issue of negative interference is still unclear, as is the extent of false decrease in creatinine values in patients who are given these catecholamines and are the focus of this investigation. The current perception among the caregivers is that all creatinine values are suspect in these patients.

A total of 58 blood samples collected from 26 patients receiving dopamine and or dobutamine infusions were included in this study. Forty-two of the sample collections were from line draws (PICC or central line with two or more ports), and the remaining were peripheral vein draws. The limited number of peripheral vein draws was due to the reluctance (from both the patients and the nurses) for venipuncture collection when the catheter lines were available for blood draw. Creatinine level in the samples was estimated by the routine enzymatic creatinine assay using peroxidase reaction and the Jaffe method on the Roche Cobas 502 instrument.

None of the peripheral vein–drawn samples had any interference from the catecholamines in either of the creatinine assays. In addition, none of the samples collected from the catheter lines showed any interference with the Jaffe creatinine assay, but nine out of 42 samples collected from line draws had negative interference with the enzymatic creatinine assay. The extent of false decrease in creatinine values varied from 18% to 74% in these nine samples.

In summary, only limited number of samples collected by line draws have negative interference (with enzymatic creatinine assay), and the interference can be overcome by testing those samples with the Jaffe creatinine assay.