Urine test strips: reliability of semi-quantitative findings under tropical conditions

Abstract

Semi-quantitative urinalysis with urine reagent strips (URS) for erythrocyturia (EU), leucocyturia (LU) and proteinuria (PU) was performed in Congolese and Sudanese school children with Schistosoma haematobium and/or S. mansoni infection. Quantitative urinalysis was performed on the same specimen using microscopy and a Neubauer counting chamber for EU and LU and the Coomassie blue dye-binding assay for PU. Microscopically detectable EU of more than 10 cells/microliters was found in 63% of all samples and LU of more than 20 cells/microliters was found in 60% of all samples. With the Coomassie blue method, PU of more than 150 mg/l was detected in 51% of all samples. URS gave positive results of grade 1-3 for EU in 69% of all samples, for LU in 63% of all samples and for PU in 66% of all samples. The sensitivity and specificity of URS compared with standard reference methods were as follow: EU 95% and 75%, LU 81% and 81% and PU 90% and 56%. When the results of all three test were combined, URS differentiated abnormal from normal urine specimens with a sensitivity of 94% and a specificity of 70%. Median quantitative results showed a good correlation with semiquantitative URS readings for all parameters, but there was a wide range of URS scores. We concluded that URS sensitivity detect urinary abnormalities and thus may be used as a general screening method under field conditions when more specific methods cannot be performed.(ABSTRACT TRUNCATED AT 250 WORDS)