URIT 11F dipstick for proteinuria testing: Comparison with quantitative protein assay and evaluation of the diagnostic accuracy for proteinuria detection in a outpatient population

Abstract

The purpose of this study is to evaluate the diagnostic performances of URIT 11F urine dipstick assay for the detection of proteinuria comparing it with a quantitative method. 5743 urine test results [urine dipstick, urine protein and creatinine concentrations and the calculated protein to creatinine ratio (PCR)] were collected from outpatients with various clinical conditions. The agreement between the URIT 11F urine dipstick and quantitative protein assay was examined. To evaluate the accuracy of urine dipstick results for proteinuria detection, we used two different cutoffs: PCR ?200 mg/g and ?150 mg/g. Dipstick test results (negative, trace, 1+, 2+, 3+) were allocated to five levels of urine protein concentration (<14, 14-30, 30.1-100, 100.1-300, >300 mg/dL) respectively. There was an agreement with a Kappa coefficient of 0.341 and p<0.001. When PCR ?200 mg/g was used as cut-off and “> negative” was classified as a positive dipstick result, the agreement of the URIT 11F dipsticks improved substantially. The findings of our study show a fair agreement between URIT 11F dipstick results and the quantitative method for urine protein. However, our results show also a high number of false negative results with dipstick testing. While second level laboratory testing can eliminate the false positive results, false negative results could cause a delay in beneficial early treatment of incipient nephropathy. For this reason, more sensitive proteinuria screening test for patients with potential early stage renal diseases should be used. © 2019 Biomedia. All rights reserved.