Introduction Sysmex XN‐9100™ (Sysmex, Kobe, Japan) system has an optional White Progenitor Cell (WPC) channel. While the White Differentiation (WDF) channel reports a combined flag for blasts/abnormal lymphocytes, WPC channel specifies flagging into a separate flag for each cell type or removes the flag entirely. Aim of this study was to evaluate the added value of this WPC channel in the detection of malignant samples. Methods Routine blood samples analyzed on Sysmex XE‐5000 with flagging for either blasts, abnormal lymphocytes, or atypical lymphocytes (n = 630) were selected for testing on Sysmex XN‐9100, resulting in a reflex WPC analysis in 420 samples. All samples were microscopically evaluated with DI‐60 digital cell imaging analyzer. Results WPC reflex testing resulted in a suspect flag ("blasts" and/or "abnormal lymphocytes") in 334 samples, which was confirmed microscopically in 38% (128/334). In all true positive samples, WPC correctly classified the initial WDF flag in either "blasts" flag or "abnormal lymphocytes?" flag in 75%. Only 12% (50/420) of WDF "blasts/abnormal lymphocytes" positive samples became negative after WPC reflex testing. Subgroup analysis showed differences between the "pediatric" versus "adult" groups and the "hematological/chemotherapy" versus "nonhematological/nonchemotherapy" groups in specificity and smear reduction. Conclusion Overall, WPC reflex testing showed good sensitivity (99%); however, the specificity remains poor (29%). Using reflex WPC to the WDF channel resulted in a 12% reduction of the smear review rate. Although the WPC channel offers different interesting advantages, additional topics and a specific workflow should be applied to optimize the use of this channel.

Objectives: Coronavirus disease 2019 (COVID-19) was first discovered in Wuhan, China, in December 2019, and soon spread around the entire world. As no effective treatment is known, prediction of disease severity is very important in order to estimate a patients outcome. Aim of this study was to evaluate routine hematology parameters in time after admission. Methods: Data from routine blood analyses from confirmed COVID-19 cases admitted to the University Hospital of Leuven in Belgium were collected. COVID-19 patients (n = 197) were assigned to three groups: a 'non-ICU' group, a 'ICU' group and a 'deceased' group. A control group of 60 Influenza A (non-COVID-19) patients was also included. The parameters evaluated were platelet count (PLT, 10 9 /L), hemoglobin concentration (Hb, g/dL), leukocyte count (LEU, 10 9 /L), neutrophil count (NEU, %), eosinophil count (EO, %), lymphocyte count (LYM, %) and monocyte count (MONO, %). Results: Deceased COVID-19 patients had significant lower platelet count, higher leukocyte/ neutrophil count, and lower eosinophil/lymphocyte/monocyte count compared to recovered patients. Especially lymphocyte count showed important differences; they were significantly lower between day 9 and 12 after admission making this time window important in predicting clinical worsening of a patient. Conclusion: Patients with COVID-19 with poor outcome showed significant differences in results of routine hematological parameters compared with patients that recovered. Especially lymphocyte count can be helpful in the prediction of a patients outcome.

Introduction: Flow cytometric panels for the investigation of lymphoproliferative disorders, such as the EuroFlow Lymphoid Screening Tube (LST), often fail to demonstrate T-cell clonality, as a suitable clonality marker was unavailable until recently. Aim of this study was to evaluate the added value of supplementing TRBC1, a flow cytometric T-cell clonality marker, to the LST. Methods: Flow cytometric analysis was performed on 830 routine samples referred to our lab for suspicion of hematological malignancy. T-cells with monotypic TRBC1-expression were additionally characterized with a 12-color T-cell tube and molecular T-cell receptor gamma gene rearrangement (TRG).Results: LST analysis revealed 97 (11.7%) samples with the presence of a monotypic T-cell population according to TRBC1, including 21 (2.5%) "high-count" (≥500 cells/ μL blood or ≥15% of lymphocytes) and 76 (9.2%) "low-count" (<500 cells/μL blood or <15% of lymphocytes) populations. Clinical symptoms indicative for T-CLPD could be correlated to 11/21 "high-count" and 17/76 "low-count" monotypic T-cell populations. Molecular TRG analysis demonstrated a monoclonal result in 76% (16/21) of "high-count" samples and in 64% (42/66; 10 samples not tested) of "low-count" samples, but also in 9/20 samples with polytypic TRBC1 results. Conclusion: Analysis of an LST tube supplemented with TRBC1 led to the detection of a high number of monotypic T-cell populations. The detection of numerous small monotypic T-cell populations raises the question of their clinical significance. A possible flowchart for assessment of these populations, based on the available literature, is proposed. Molecular TRG analysis is complementary and cannot be omitted from T-cell clonality assessment.

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Objective: Commercial kits of column tests for pre-transfusion testing have progressively replaced conventional tube tests in most laboratories. Aim of this study was to compare three commercial test cell panels for the identification of irregular red blood cell (RBC) alloantibodies. Overall, 44 samples with a positive indirect antiglobulin test (IAT) by routine testing were used for comparison of following panels: Ortho RESOLVE ® panelC (Ortho Clinical Diagnostics (OCD), Milan, Italy), ID-DiaPanel(-P) (Bio-Rad Laboratories, CA, USA) and Identisera Diana(P) (Grifols, Barcelona, Spain). Column agglutination techniques were used, with microtubes containing either microgel (Bio-Rad/Grifols) or glass bead microparticles (Ortho). Results: Alloantibody identification was possible in 38 samples, of which identical identification was shown in 33 samples by all methods. The remaining samples showed differences between certain methods, with the gel card system being superior to the glass card system for analyzing stored samples Considering that not all samples were evaluated in all three methods, the concordance rate reached 100% between Bio-Rad and Grifols, 90.5% between Bio-Rad and OCD, 86.5% between OCD and Grifols and 90.5% between all methods. Although differences in sensitivities were seen for specific antibodies, the three methods showed comparable performance for the identification of RBC alloantibodies.

Background Hemolytic disease of the fetus and newborn (HDFN) due to rhesus D (RhD) immunization is a potentially life‐threatening situation for which use of Rh Immunoglobulin (RhIg) has decreased risk drastically. Determination of fetal RHD on maternal plasma can be used to restrict prenatal RhIg administration to women carrying an RhD‐positive child, avoiding unnecessary administration of blood‐derived products. Study Design and Methods The aim of this study is to determine the performance of fetal RHD typing in our center. We prospectively collected 205 fetal RHD and 127 serological cord blood RhD data from RhD‐negative women starting at 11 weeks of pregnancy (from October 2019 to October 2021). Real‐time polymerase chain reaction targeting RHD exon 5 and 7 was used, similar to the screening program in The Netherlands, supplemented with an amplification control (beta‐actin; ACTB) and a sex determination marker located on the Y‐chromosome (SRY gene). Results Fetal RHD testing reached a sensitivity and specificity of 100%. No false‐negative nor false‐positive results were reported. Inconclusive results (6%, 13/205) were due to weak amplification in 10 cases, a maternal RHD variant in 2 cases (RHD*01N.71 and partial DVI), and a fetal RHD variant (partial DVI) in 1 case. Unnecessary administration of RhIg prophylaxis was avoided in 33% of cases and on the other hand was administered in one case (fetal partial DVI) which would have been missed with cord blood serology. Discussion This study demonstrates the high accuracy of routine prenatal fetal RHD gene screening after 11 weeks of pregnancy, encouraging routine clinical practice.

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