IMMUNOASSAYS FOR SERUM AND URINE MYOGLOBIN - MYOGLOBIN CLEARANCE ASSESSED AS A RISK FACTOR FOR ACUTE-RENAL-FAILURE

We compared four immunoassays for serum and urine myoglobin. Within-ru n CVs were 5-13%, with biases seen between assays. Myoglobin was stabl e for 1 month in serum and 12 days in urine when the pH was adjusted t o between 8.0 and 9.5. Hemoglobin caused no interference. We assayed 9 1 pairs of serum and timed urine specimens from 41 patients admitted f or acute trauma or rhabdomyolysis. Most were treated with mannitol and alkalinization. Upon initial presentations, 21 patients with either l ow serum myoglobin concentrations (<400 mu g/L) or high myoglobin clea rances (greater than or equal to 4 mL/min) had normal creatinine clear ances and no clinical evidence of renal disease. The remaining 20 had low myoglobin clearances. Seven were in rhabdomyolysis-induced acute r enal failure, or subsequently developed this complication. We suggest that low myoglobin clearance may indicate a high risk for developing r enal failure or may be an early marker for kidney dysfunction. Low myo globin clearance may prove useful in indicating failure of prophylacti c treatment to clear myoglobin.