Contagem de neutrófilos em doentes leucopénicos
: comparação do autoanalisador hematológico XE-2100 com o sistema de análise de imagem cellavision DM96

  • Cristina Maria Fernandes da Silva (Student)

Student thesis: Master's Thesis

Abstract

Febrile neutropenia (FN) is associated with deterioration of quality of life, resource consumption associated with treatment and reduced or deferred therapy. The cure rate or disease-free survival may also be compromised, and the mortality rate is approximately 5% in unselected populations (ranging from 1% for solid tumors and 11% for hematologic malignancies). Although the incidence of NF is generally poor, it can reach 33% or more in hematologic malignancies. Thus, in the context of a Cancer Center, FN is a problem of great clinical importance, requiring a rapid and accurate evaluation of the blood by the laboratory of Hematology for taking critical decisions. Currently, the laboratories of Hematology perform the assessment of blood samples by means of automated systems allowing for total and differential leucocyte count. However, in cases of leukopenia, doubts remain about the reliability of this count and the standard of evaluation - manual count – is a time consuming method which requires significant experience. Thus, the objectives of this study were: (1) assess the neutrophil count in leukopenic patients (total leukocyte count between 0.1 x 109 / L and 1.5 x109 / L), (2) to compare the absolute neutrophil count (ANC) held in hematologic autoanalyzer Sysmex XE-2100 system with the image analysis system CellaVision DM96, and (3) establish the threshold of confidence to report the value of neutrophils obtained in the automated counter Sysmex XE-2100 in a laboratory of Hematology. Blood samples of leukopenic patients routinely analyzed in the laboratory of Hematology whose total leukocyte count obtained on the XE-2100 was between 0.1 x 109 / L and 1.5 x 109 / L were enrolled for this study. The corresponding smears were simultaneously analyzed in the Blood Differential Software of CellaVision. From a total of 267 samples analyzed, we excluded 19 (7.1%) owing to counting error in the XE-2100, and 20 (7.5%) because they had a cell count of less than 20 in CellaVision. Of the 19 results with error reading in XE-2100, it was possible to obtain the ANC in CellaVision in 16 (84%). Comparing the ANC determined by automatic analyzer XE-2100 and the image analysis system CellaVision, we found that the mean difference was not statistically significant (Student’s t test for paired samples, p>0.05). The index of overall correlation between the results of the two systems was high and statistically significant (Pearson test, r=0.959, p<0.001). The same analysis was performed according to the absolute count of leukocytes (WBC), considering the intervals of the percentiles of the distribution. The correlation index increased as the number of leukocytes increased, with values always above 92% and statistically significant (p<0.001). We concluded that the XE-2100 automated counter provides values that allow the ANC to be reported with confidence on leukopenic patients. This may, on the one hand, decrease the response time of the laboratory, and secondly, to increase the available information. Notwithstanding, CellaVision seems to be a useful tool since it allows the smear review, monitor developments in hematological parameters, archive images, and contribute to training and teaching of morphology.
Date of AwardFeb 2011
Original languagePortuguese
Awarding Institution
  • Universidade Católica Portuguesa
SupervisorRui Manuel Ferreira Henrique (Supervisor) & Carlos Alberto da Costa Mendes (Co-Supervisor)

Designation

  • Mestrado em Análises Clínicas e Saúde Pública

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