Reliability of immunoturbidimetric urine albumin determination for normal and moderately high values

The value of albuminuria determination is commonly accepted in the monitoring of renal function, particularly in diabetic patients. This may be achieved in different ways and using different assay kits. The aim of this study was to assess the reliability of immunoturbidimetric measurements by comparing the results obtained by two different methods in our laboratory. Therefore we measured albuminuria of 54 patients monitored for their diabetes, with normal to moderately high albuminuria, according to two methods: Microalbumin reagent (Beckman Coulter) on a Unicel DxC 600 (Beckman Coulter) and Albumin Turbiquant reagent (Dade Behring, Siemens) on a Turbitimer system (Dade Behring, Siemens). It was then possible to study the correlation between the two techniques. Our results suggest that although this correlation is excellent, the values differ significantly: the results observed with the Siemens method are higher by about 10%. It seems legitimate to think that a correction should be applied, depending on the used method. In addition, it appears that standardization is necessary, concerning analytical stage but although urine collection, pre-analytical stage or reporting and interpretation of results.