Digital morphology in hematology diagnosis and education: The experience of the European LeukemiaNet WP10.

Hematological diagnostics is based on increasingly precise techniques of cellular and molecular analysis. The correct interpretation of the blood and bone marrow smears observed under an optical microscope still represents a cornerstone. Precise quantitative and qualitative cytomorphological criteria have recently been codified by up-to-date guidelines for diagnosing hematopoietic neoplasms. Morphological analysis has found formidable support in digital reproduction techniques, which have simplified the circulation of images for educational or consultation purposes. From 2007 to 2019, the Working Group WP10 of European LeukemiaNet (ELN) used, in annual exercises, digital images to support training in cytomorphology and verify harmonization and comparability in the interpretation of blood and bone marrow smears. We describe the design, development, and results of this program, which had 741 participants in-person or remotely, to which 2055 questions were submitted regarding the interpretation of cytomorphological images. We initially used circulation and presentation of digital microphotographs and then introduced a virtual microscopy (VM). Virtual slides were obtained using a whole slide imaging technique, similar to the one largely used in histopathology, to produce digitized scans of consecutive microscopic fields and reassembles them to obtain a complete virtual smear by stitching. Participants were required to identify cells in labeled fields of view of the virtual slides to obtain a morphological diagnosis. This work has demonstrated substantial improvements in diagnostic accuracy and harmonization with the VM technique. Between-observer concordance increased from 62.5% to 83.0%. The integrity of the digitalized film image, which provides a general context for cell abnormalities, was the main factor for this outcome.

Hematological performance of a last generation automated blood cell counter: The Mindray BC-6800 Plus.

INTRODUCTION: Hematology analyzers produce reliable, reproducible, precise, accurate results, as well as a premicroscopic characterization of abnormal samples. We have evaluated the clinical performance of a new blood cell counter, which has been temporarily made available to our hematology laboratory. METHODS: Over four months, we analyzed with the Mindray BC-6800 Plus more than 1000 samples with a high incidence of hematological abnormalities, using recommended ICSH and CLSI protocols. We have also assessed flagging efficiency for abnormal cells and scattergram cell distribution. RESULTS: From a quantitative point of view, our assessment has identified state-of-the-art level reproducibility, excellent linearity, stability over 48°C at 4°C for the conventional parameters, lack of carry-over (<0.2%), and comparability with the routine instruments. These features would make the instrument suitable for immediate and smooth introduction in the hematology laboratory. Flags for abnormal cells are efficient; flag for blast cells has high sensitivity and predictive value of negative results. Additional benefits are provided by a competent interpretation of cell distribution scattergrams in samples from patients with specific hematological disorders. CONCLUSION: We have demonstrated good analytical and useful diagnostic performance of this new instrument, including effective selection of abnormal samples for informed microscope morphological analysis.

The role of molecular typing and perfect match transfusion in sickle cell disease and thalassaemia: An innovative transfusion strategy.

Chronic red blood cell transfusions remain an essential part of supportive treatment in patients with thalassaemia and sickle cell disease (SCD). Red blood cell (RBC) transfusions expose patients to the risk of developing antibodies: RBC alloimmunization occurs when the immune system meets foreign antigens. We created a register of extensively genotyped donors to achieve a better matched transfusion in order to reduce transfusion alloimmunization. Extended RBC antigen typing was determined and confirmed by molecular biology techniques using Human Erythrocyte Antigen (HEA) BeadChip (BioArray Solutions Ltd., Warren, NJ) in periodic blood donors and in patients with thalassaemia and SCD. During 3 years, we typed extensively 1220 periodic blood donors, 898 male and 322 female. We also studied 10 hematologic patients affected by thalassaemia and sickle cell disease referred to our institution as candidate to periodic transfusions. Our patients (8 females and 2 males with a median age of 48 years, range 24-76 years), extensively typed using molecular techniques and screened for RBC alloantibodies, were transfused with a median of 33.5 RBC units. After three years of molecular typing, the "perfect match" transfusion strategy avoided new alloantibodies development in all studied patients.

Weak D Type 4.2.2 (DAR1.2) in an African child: Serology and molecular characterization.

The weak D phenotype is represented by a group of RHD genotypes that code for alterated RhD proteins associated with a reduced RhD expression on red blood cell. By routine serology, some partial D variants are likely to be missed. In this report we describe the case of a three-year-old Black African child with a "unclear" reaction with monoclonal anti-D. We analyzed the blood sample of the child with different methods to conclude that it is a case of DAR 1.2 (weak D 4.2.2) and that it must be transfused with D negative erithrocytes.