Evaluation of erythrocyte dysmorphism by light microscopy with lowering of the condenser lens: A simple and efficient method.
OBJECTIVE
To demonstrate that the evaluation of erythrocyte dysmorphism by light microscopy with lowering of the condenser lens (LMLC) is useful to identify patients with a haematuria of glomerular or non-glomerular origin.


METHODS
A comparative double-blind study between phase contrast microscopy (PCM) and LMLC is reported to evaluate the efficacy of these techniques. Urine samples of 39 patients followed up for 9 months were analyzed, and classified as glomerular and non-glomerular haematuria. The different microscopic techniques were compared using receiver-operator curve (ROC) analysis and area under curve (AUC). Reproducibility was assessed by coefficient of variation (CV).


RESULTS
Specific cut-offs were set for each method according to their best rate of specificity and sensitivity as follows: 30% for phase contrast microscopy and 40% for standard LMLC, reaching in the first method the rate of 95% and 100% of sensitivity and specificity, respectively, and in the second method the rate of 90% and 100% of sensitivity and specificity, respectively. In ROC analysis, AUC for PCM was 0.99 and AUC for LMLC was 0.96. The CV was very similar in glomerular haematuria group for PCM (35%) and LMLC (35.3%).


CONCLUSIONS
LMLC proved to be effective in contributing to the direction of investigation of haematuria, toward the nephrological or urological side. This method can substitute PCM when this equipment is not available.
Barros Silva
Gyl Eanes
GE
Department of Pathology, Faculty of Medicine of Ribeirão Preto, University of Sao Paulo, Brazil.
Costa
Roberto Silva
RS
Ravinal
Roberto Cuan
RC
Saraiva e Silva
Jucélia
J
Dantas
Marcio
M
Coimbra
Terezila Machado
TM
D000293:Adolescent; D000328:Adult; D000368:Aged; D019540:Area Under Curve; D004311:Double-Blind Method; D004867:Equipment Design; D004913:Erythrocytes, Abnormal / Q000473:pathology*; D005260:Female; D006417:Hematuria / Q000175:diagnosis* / Q000209:etiology / Q000652:urine; D006801:Humans; D007674:Kidney Diseases / Q000150:complications / Q000175:diagnosis* / Q000652:urine; D008027:Light; D008297:Male; D008853:Microscopy / Q000295:instrumentation / Q000379:methods*; D008858:Microscopy, Phase-Contrast; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014556:Urine / Q000166:cytology; D055815:Young Adult