Best cutoff of the percentage of dysmorphic erythrocytes evaluated by different methods associated or not with the measurement of macroalbuminuria and microalbuminuria in the diagnosis of the origin of hematuria

• Grant number: 10/14686-3
• Support Opportunities: Scholarships in Brazil - Master
• Start date: September 01, 2011
• End date: February 28, 2013
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Luis Cuadrado Martin
• Grantee: Marila Gaste Martinez
• Host Institution: Faculdade de Medicina (FMB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

There is disagreement over the literature regarding the performance of phase microscopy to assess the origin f hematuria (glomerular or nonglomerular). This shows the need for further investigation in order to validate the best form of morphological evaluation of hematuria. The aims of this study were to determine the optimal cutoff point percentage for different patterns of dysmorphic cells in the detection of glomerular hematuria by conventional optical microscopy and phase contrast microscopy, to verify whether the presence of proteinuria or albuminuria may assist in the diagnosis of hematuria and also to establish an optimal cutoff point for this parameter. One hundred thirty-one urine samples were blinded evaluated at the Faculdade de Medicina de Botucatu, 66 samples of patients with glomerulopathies and 65 samples of patients with nephrolithiasis. Isolated samples with density greater than 1007 and with more than 5 erythrocytes per high-power field were used. The presence and percentage of codocytes and acanthocytes were verified by conventional optical microscopy using fresh and fixed urinary sediment subjected to Papanicolaou and Panótico Rápido LB staining and fresh urinary sediment was evaluated by phase contrast microscopy. Proteinuria and albuminuria rates were determined. The results of these methods were compared using linear regression analysis and Bland-Altman diagram of dysmorphic red blood cells. ROC curve plots were generated to determine the area under the ROC curve (AUC) and also an optimal cutoff point with the highest sum of sensitivity and specificity. At this point, it was possible to calculate sensitivity (TPR) and specificity (ES), positive predictive value (PPV) and negative predictive value (NPV). In conventional optical microscope with fresh urinary sediment, the AUC of total dysmorphic erythrocytes showed the best result for the diagnosis of hematuria with AUC (IC 95%) of 0,93 (0,89-0,97), cutoff point e26% of dysmorphic RBC´s with TPR of 82%, ES of 94%, PPV of 93% and NPV of 84%. In phase contrast microscope, the AUC of acanthocytes had the best performance for the diagnosis of hematuria with AUC (IC 95%) of 0,93 (0,88-0,98), cutoff point e8% of dysmorphic RBC´s, TPR of 94%, ES of 89%, PPV of 90% and NPV of 94%. As well as in fixed urinary sediment of Papanicolaou staining, the total dysmorphic erytrhrocytes had the best performance for the diagnosis of hematuria, with AUC (IC 95%) of 0,91 (0.86-0,96), cutoff point e20% of dysmorphic RBC´s with TPR of 92%, ES of 85%, PPV of 86% and NPV of 92%. In Panótico Rápido LB staining, total dysmorphism also showed the best result with AUC (IC 95%) of 0,90 (0,84-0,98), cutoff pointe 20% of dysmorphic RBC´s with TPR of 0,86%, ES of 85%, PPV of 85% and NPV of 86%. All methods of evaluation showed a statistically significant discriminatory power, as well as proteinuria which showed AUC (IC 95%) of 0,79 (0,71-0,87), cutoff point e 300mg/g of creatininuria with TPR of 67%, ES of 88%, PPV of 84% and NPV of 71%, and also for albuminuria which showed AUC (IC 95%) of 0,82 (0,75-0,90), cutoff point >54mg/g of creatininuria with TPR of 76%, ES of 85%, PPV of 83% and NPV of 77%. In conclusion, this study showed that it is possible to confirm the origin of hematuria by evaluating the erythrocyte dysmorphism in urinalysis using conventional optical microscope with fresh and fixed sediment and also phase contrast microscope. Although proteinuria and albuminuria can be used to diagnose the origin of hematuria, evaluation of erythrocyte dysmorphism was the best method to differenciate glomerular hematuria.Key words: Erythrocyte Dysmorphism, Acanthocytes, Codocytes, Proteinuria, Albuminuria, Optical Conventional Microscope, Phase Contrast Microscope (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

MARTINEZ, MARILA GASTE; SILVA, VANESSA DOS S.; DO VALLE, ADRIANA P.; AMARO, CARMEN R. P. R.; CORRENTE, JOSE E.; MARTIN, LUIS CUADRADO. Comparison of Different Methods of Erythrocyte Dysmorphism Analysis to Determine the Origin of Hematuria. NEPHRON CLINICAL PRACTICE, v. 128, n. 1-2, p. 88-94, DEC 2014. (10/14686-3, 10/11591-1)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

MARTINEZ, Marila Gaste. Avaliação dos diferentes métodos de análise do dismorfismo eritrocitário, assim como a quantificação da proteinúria e a albuminúria na determinação da origem de hematúria. 2013. Master's Dissertation - Universidade Estadual Paulista (Unesp). Faculdade de Medicina. Botucatu Botucatu.