Evaluation on a radioimmunoassay of α1 microglobulin (α1-m) with simplified procedures

A newly established double antibody radioimmunoassay (RIA) was fundamentally and clinically evaluated. Original procedures were partially modified as follows: Sample volume for serum and urine was changed to 25μl, and thus 200 mg/l of α1-m standard was prepared using 50 μl of original standard solution (100 mg/l). The results were satisfactory in sensitivity (0.3 mg/l obtained from -2SD method), intraassay precision with its coefficient variation (CV) ranging from 3.0 to 7.4%, interassay precision with its CV ranging from 3.0 to 10.7%, and recovery with the mean value of 102.4% in serum and 108.2% in urine respectively. There were no changes about α1-m value between diluted (2 times) and undiluted with high concentration samples. Normal levels of α1-m were less than 25 mg/l is serum and less than 10 mg/l in urine. The present results indicate that the determination of α1-m could be very simple and useful for the most sensitive screening test for the evaluation of renal function. (author)