[Evaluation of electroimmunoassay and clinitek-100 for detection of microalbuminuria]

ABSTRACT

Detection of microalbuminuria is an important laboratory test for evaluation of diabetic complications. A reliable method for determination of urine albumin is critical in this process. In the present study, we set-up and evaluated an electroimmunoassay [EIA] method for measearing the amount of albumin in urine. The reliability of Clinitek-100 Instrument was evaluated for screening of microalbuminuria as well. In this study which was the evaluation of a diagnostic test, anti human albumin antiserum was prepared following the immunization of rabbit and the EIA method was set-up for albumin determination. The ratio of albumin to creatinine, as the index of albumin excretion rate, were calculated for 61 urine samples of diabetic patients. Finally, the reliability of EIA and clinitek-100 for detection of microalbuminuria were evaluated. An enzyme-linked immunosorbent assay [ELISA] was used as a reference method for determination of urine albumin and for detection of microalbuminuria as well. The detection limit for EIA method was 2 mg/L, with analytical range of 2-200 mg/L. The intra-assay coefficient variation [C.V] of various albumin concentrations were 3.34 to 5.57%, whereas the regression coefficient was 0.996 [r=0.996]. The sensitivity and specificity of EIA-test for detection of microalbuminuria were 95% and 83%, respectively. The sensitivity and specificity of Clinitek-100 for microalbuminuria detection were 67% and 94%, respectively. The EIA is a precise and specific method for determination of urine albumin and detection of microalbuminuria, but it is time consuming and unsuitable for single test reports. Clinitek-100 is specific and fast for delection of microalbuminuria. This method is suitable for single reports, but its negative results in test are controversial. We suggest that more care be taken for the clinitek-100 results and the negative results should be re-examined by other sensitive methods: