FALSELY-ELEVATED SERUM CREATININE VALUES IN DIABETIC-KETOACIDOSIS - CLINICAL IMPLICATIONS

Unusual elevations of serum creatinine (S-CR) out of proportion to increases in serum urea nitrogen (S-UN) are frequently observed in patients with diabetic ketoacidosis when S-CR is measured by the Jaffe end-point reaction. This was ascribed to interference from acetoacetate but this is not observed with kinetic DuPont ACA methodology. Eighteen patients with diabetic ketoacidosis were studied; S-CR measurements were done using the end point Technicon SMA 6/60 method (group A, 10 patients) or the kinetic DuPont ACA method (group B, 8 patients). The values for S-CR in group A patients (mean value and S-D were 3.3 .+-. 1.1 mg/dl) were significantly from group B patients (1.6 .+-. 0.24 mg/dl) (P < 0.01). A significant positive correlation was obtained between the excess anion gap and S-CR in group A patients (r = +0.81, P < 0.01). The results from 2 patients in whom serial measurements of S-UN, S-CR and the anion gap were carried out further demonstrate the analytical interference. In diabetic ketoacidosis elevated creatinine values measured by an end-point method should not necessarily be interpreted as evidence of significant renal impairment and if possible should be verified by a kinetic method which is free of ketone/interference.