Differentiation of glomerular and non-glomerular hematuria in children by measurement of mean corpuscular volume of urinary red cells using a semi-automated cell counter

Urine samples from 110 children and adolescents with micro- or macrohematuria were compared using phase-contrast microscopy and a semi-automated cell counter to differentiate glomerular from non-glomerular hematuria. Glomerular hematuria, defined by clinical criteria from biopsy and standard chemical evaluation, was observed in 73 patients (group 1): non-glomerular hematuria was found in 37 patients (group 2). The latter group underwent urological operation and had normal urine before operation. Mean corpuscular erythrocyte volume (MCVU) and percent of dysmorphic erythrocytes were determinated. To exclude the influence of mean erythrocyte volume of blood erythrocytes (MCVB), MCVB was determined and additionally the quotient of MCVU/MCVB was calculated (MCVUB). The percentage of dysmorphic erythrocytes differed significantly between the two groups ((75 ± 13% in group 1 versus 38 ± 27% in group 2 (mean ± SD); p < 0.01), MCVU (34.0 ± 11.1 fl in group 1 versus 55.5 ± 16.3 fl in group 2; p < 0.01) and MCVUB (0.41 ± 0.14 in group 1 versus 0.67 ± 0.20 in group 2; p < 0.01). When glomerular hematuria was defined on the basis of more than 80% dysmorphic erythrocytes, the sensitivity of phase-contrast microscopy was 0.52, specificity versus 0.96 and efficiency 0.64. When glomerular hematuria was defined asn <50fl MCVU, sensitivity was 0.92, specificity 0.57 and efficiency 0.80 and as <0.06 MCVUB, sensitivity was 0.89, specificity 0.62 and efficiency 0.80. The correlation coefficient between MCVU and dysmorphic erythrocytes was -0.71 ( p < 0.01). The differentiation of glomerular and non-glomerular hematuria in children by determination of MCVU appears to be equivalent to and easier to perform than phase-contrast microscopy.