ADAPTATION OF A QUANTITATIVE IMMUNOASSAY FOR URINE MYOGLOBIN - PREDICTOR IN DEFECTING RENAL DYSFUNCTION

Myoglobinuria, subsequent to rhabdomyolysis, may cause acute renal fai lure, For this reason, many qualitative and quantitative tests have be en developed for the detection of myoglobin in urine. The authors desc ribe the adaptation and optimization of the Stratus II serum myoglobin immunoassay to quantify urine myoglobin. In addition, the assay was u sed to accurately determine urine myoglobin concentrations in subjects at potential risk for myoglobin-induced renal dysfunction and the res ults obtained compared to conventional qualitative methods for urine m yoglobin. The assay demonstrated with-in run and between-run coefficie nt of variations (CVs) of 6.2% and 7.2%., respectively, was linear fro m 0-950 mu g/L, demonstrated good recovery, and was free from interfer ence by hemoglobin, creatinine, and urea. Specimens were diluted with 0.1 mol/L phosphate buffer, pH 9.0 containing 3% bovine serum albumin before analysis. Myoglobin was assayed on urine obtained from 30 patie nts suspected of having myoglobinuria, Fifteen of 17 patients with ser um creatinine greater than 1.4 mg/dL had myoglobin concentrations grea ter than 20,000 mu g/L, whereas the remaining 13 patients with normal serum creatinine had urine myoglobin concentrations of less than 18,00 0 mu g/L. If serum creatinine is used as an indicator of renal functio n, it would appear that accurate measurement of urine myoglobin may fa cilitate identification of patients with increased susceptibility to m yoglobin-induced acute renal failure.