ABSTRACT
Minimal residual disease is the most powerful predictor of outcome in acute leukemia and is useful in therapeutic stratification for acute lymphoblastic leukemia protocols. Nowadays, the most reliable methods for studying minimal residual disease in acute lymphoblastic leukemia are multiparametric flow cytometry and polymerase chain reaction. Both provide similar results at a minimal residual disease level of 0.01% of normal cells, that is, detection of one leukemic cell in up to 10,000 normal nucleated cells. Currently, therapeutic protocols establish the minimal residual disease threshold value at the most informative time points according to the appropriate methodology employed. The expertise of the laboratory in a cancer center or a cooperative group could be the most important factor in determining which method should be used. In Brazil, multiparametric flow cytometry laboratories are available in most leukemia treatment centers, but multiparametric flow cytometry processes must be standardized for minimal residual disease investigations in order to offer reliable and reproducible results that ensure quality in the clinical application of the method. The Minimal Residual Disease Working Group of the Brazilian Society of Bone Marrow Transplantation (SBTMO) was created with that aim. This paper presents recommendations for the detection of minimal residual disease in acute lymphoblastic leukemia based on the literature and expertise of the laboratories who participated in this consensus, including pre-analytical and analytical methods. This paper also recommends that both multiparametric flow cytometry and polymerase chain reaction are complementary methods, and so more laboratories with expertise in immunoglobulin/T cell receptor (Ig/TCR) gene assays are necessary in Brazil.
Subject(s)
Humans , Flow Cytometry , Immunophenotyping , Neoplasm, Residual , Precursor Cell Lymphoblastic Leukemia-LymphomaABSTRACT
Introduction: The Sysmex® XE-2100D is a multiparameter hematology analyzer designed for hematology testing in samples with ethylenediamine tetraacetic acid (EDTA). Objectives: Considering the importance of this hematology analyzer for clinical and laboratory practice, the objective of this study was to evaluate its analytical performance, comparing the obtained results with quality specifications described in literature. Material and method: In the evaluation of analytical performance, according to recommendations of the document H26-A2 of the Clinical and Laboratory Standards Institute (CLSI), intra-run imprecision, inter-run imprecision, linearity, carryover, autosampler evaluation, clinical sensitivity of the atypical lymphocytes flag (n = 400 samples) were included, as well as the comparison between automated and manual leukocyte differential count (n = 400 samples), based on an adaptation of the document H20-A2 of CLSI. Results: Repeatability, reproducibility, linearity and carryover were satisfactory according to the manufacturer's specifications. The clinical sensitivity of the atypical lymphocytes flag showed efficiency, sensitivity and specificity of 92.5%, 65.2% and 94.1% respectively. The correlation coefficients between the automated and manual differential counts of neutrophils, lymphocytes, monocytes, eosinophils and basophils were 0.991, 0.99, 0.872, 0.974 and 0.557, respectively. Conclusions: The results were in accordance with quality specifications described in literature, indicating reliability in Sysmex® XE-2100D. This fact ensures certainty to both laboratory professionals and medical staff. We conclude that the Sysmex® XE-2100D showed excellent analytical performance, and is useful to provide reliable hematology data...
Introdução: O Sysmex® XE-2100D é um analisador hematológico multiparamétrico destinado à realização de testes hematológicos em sangue anticoagulado com ácido etilenodiamino tetra-acético (EDTA). Objetivos: Considerando a sua importância na prática clínica e laboratorial, o objetivo deste estudo foi avaliar seu desempenho analítico, comparando os resultados obtidos com especificações de qualidade descritas na literatura. Material e método: Na avaliação de desempenho analítico, conforme recomendações do documento H26-A2 do Clinical and Laboratory Standards Institute (CLSI), foram incluídos ensaios de verificação da imprecisão intraensaio ou repetitividade, imprecisão entre ensaios ou reprodutibilidade, linearidade, carryover (arraste), avaliação do mecanismo homogeneizador de amostras, sensibilidade clínica do alerta morfológico (flag) de linfócitos atípicos (n = 400 amostras) e a comparação entre a contagem diferencial de leucócitos automatizada e a manual (n = 400 amostras), baseada em uma adaptação do documento H20-A2 do CLSI. Resultados: Os ensaios de verificação da repetitividade, reprodutibilidade, linearidade, carryover (arraste) foram satisfatórios conforme especificações do fabricante. O ensaio de sensibilidade clínica do alerta morfológico (flag) de linfócitos atípicos mostrou eficiência, sensibilidade e especificidade de 92,5%; 65,2% e 94,1% respectivamente. Os coeficientes de correlação entre as contagens diferenciais automatizadas e manuais de neutrófilos, linfócitos, monócitos, eosinófilos e basófilos foram de 0,991; 0,99; 0,872; 0,974 e 0,557 respectivamente...