Detection of glomerular and non-glomerular red blood cells by automated urinary sediment analyzer

Abstract

There is increasing interest in the examination of urine sediment to differentiate between glomerular and non-glomerular hematuria. A newly developed automated urinary sediment analyzer was used for this purpose. It clearly recognized red blood cells, white blood cells, epithelial cells, bacteria and crystals by their cell size and fluorescent intensity. Ninety-eight urine samples from 31 glomerular and 67 non-glomerular lesions were analyzed by the analyzer and 69 samples, by light microscopy. According to the analysis of their histograms, a forward scatter (FSC) intensity of less than 126, where 80% of the smaller red blood cells were observed, was diagnosed as glomerular hematuria. A FSC intensity of more than 84, where 80% of the large red blood cells were counted, was non-glomerular hematuria. An FSC intensity between 84 and 126 was considered to be the overlap zone of glomerular and non-glomerular hematuria. The sensitivity for glomerular red blood cells was found to be 100% and specificity, 92.54% by means of flow cytometric analysis. On the other hand, light microscopic analysis yielded 95.83% sensitivity and 93.33% specificity for glomerular lesions. Flow cytometric analysis of the urinary red blood cells was concluded to be a fast, simple and reliable method to differentiate glomerular and non-glomerular hematuria.