[The determination of serum and urine myoglobin]

We have reviewed the current methods of determining serum and urine myoglobin. Qualitative determination of urine myoglobin has been possible for over 20 years, but the quantitative determination is a recent development. Between 1963 (spectrophotometry) and 1978 (radioimmunoassay, RIA), efforts have been made to develop a more sensitive determination method. The RIA method thus developed has a sensitivity as high as 1 ng/ml. Such methods are valuable in the diagnosis of acute myocardial infarction. Recently, simple, rapid, and non-isotopic method such as enzyme immunoassay (EIA) and latex agglutination test have been developed and made rapid determination possible. We applied the "Mb-latex [Seiken]", one such latex agglutination method to the TBA-30 R single-multi type automated analyzer. We obtained good results in the fundamental study such as in precision and accuracy. The reference ranges obtained using serum and urine samples corresponded to the values reported by others with the exception of the lower limit of the ranges. Proficiency testing data using the same reagents and same samples at five laboratories revealed some systematic biases. The reasons for such interlaboratory differences is not clear. However, these systematic biases may be due to the type of equipment, the type of calibration procedure and others including reagents and standard solutions. We are continuing our effort to improve the reliability of interlaboratory data.