[A new morphological classification of urinary erythrocytes for evaluating the source of hematuria].

For differentiation of glomerular from urological hematuria more accurately, a new morphological classification of urinary erythrocytes was studied in 74 cases of glomerular and 58 cases of urological hematuria. For each urine sample, 100 urinary erythrocytes were observed with phase-contrast microscopy and classified into 5 "glomerular" shapes (G1-G5), 5 "urological" shapes (N1-N5) and an unclassified shape. The result was that occurrence of G1, G2, G3, G4, G5 or unclassified shape group appeared significantly (P < 0.01) higher in glomerular diseases than in urological diseases, and among them G1 was the most specific shape for glomerular hematuria. Using percentage of sigma G (G1 + G2 + G3 + G4 + G5) and setting the cut-off at 20%, the sensitivity and specificity for the diagnosis of glomerular diseases were 95.9%. When percentage of G1 (doughnut-like cell with one or more blebs) was used at a cut-off of 1%, sensitivity and specificity were 75.7% and 96.5% respectively. These results were more satisfactory as compared with those in most of the previous reports. Moreover, this new classification is more objective, accurate and clear.