Considerations on ABO Genotyping Results: Lessons from ABO*AW.10 Allele Cases / 대한수혈학회지

We would like to introduce domestic subscribers of the Korean Journal of Blood Transfusion to the important aspects to be considered while selecting a reference allele and reporting a new allele candidate. ABO*A1.02 has only a single nucleotide substitution of c.467C＞T in ABO*A1.01, and when ABO*A1.01 is used as the reference allele, the ABO*AW.10 allele should be marked as having both c.467C＞T and c.784G＞A variants. Unfortunately, it has not been modified as such in the ISBT database. For this reason, in the journal Transfusion (2020), the official journal of the Association for the Advancement of Blood Biotherapies, there was a report of a new allele with c.467C＞T and c.784G＞A variants. Cases of ABO*AW.10 allele with a weak A phenotype are not uncommon in Koreans, and it is necessary to accurately mark the reference allele. The blood type A reference allele of the International Society of Blood Transfusion (ISBT) database currently used for ABO alleles reporting is based on ABO*A1.01. Therefore, it should be considered that the ABO*AW.10 allele has both the c.467C＞T and c.784G＞A variants together.

Transfusion support in hematopoietic stem cell transplantation

Transfusion support for hematopoietic stem cell transplantation (HSCT) is an essential part of supportive care, and compatible blood should be transfused into recipients. As leukocyte antigen (HLA) matching is considered first and as the blood group does not impede HSCT, major, minor, bidirectional, and RhD incompatibilities occur that might hinder transfusion and cause adverse events. Leukocyte reduction in blood products is frequently used, and irradiation should be performed for blood products, except for plasma. To mitigate incompatibility and adverse events, local transfusion guidelines, hospital transfusion committees, and patient management should be considered.

Three Cases of Anti-LW Antibody Identification at a Tertiary Hospital in Korea / 대한수혈학회지

The Landsteiner–Wiener (LW) antigen is a type of red blood cell antigen. Anti-LW appears in various situations, including alloantibodies, autoantibodies, and even transiently occurring antibodies. Anti-LW has similar characteristics to anti-D, so it can interfere with interpreting pre-transfusion tests and finding compatible blood. This paper introduces three cases in whom anti-LW was detected through antibody identification tests. All three cases were examined using the column agglutination technique with ID-DiaPanel (Bio-Rad, Hercules, CA, USA) on a LISS/Coombs card, ID-DiaPanel p (Bio-Rad) on a NaCl/Enzyme card, and ID-DiaPanel (Bio-Rad) on a LISS/Coombs card using red blood cells treated with dithiothreitol. The auto-control test, direct antiglobulin test, and umbilical cord blood test were also performed. In all three cases, the reaction with D-positive panel cells was stronger than that with the D-negative panel cells, and two of them showed a pan-agglutinated reaction in ID-DiaPanel p (Bio-Rad) with NaCl/Enzyme card. They were reported as anti-LW, and as in these cases, anti-LW can occur under a range of conditions and interfere with proper transfusion. Therefore, it is important to identify anti-LW accurately, and if anti-LW is present, the transfusion of D-negative ABO matched blood should be recommended because of the low expression of the LW-antigen. On the other hand, D-positive blood is not a contraindication when an urgent transfusion is needed.

Serial Screening for SARS-CoV-2 in Rectal Swabs of Symptomatic COVID-19Patients

We used serial rectal swabs to investigate the amount and duration of virus secretion through the gastrointestinal tract and assessed the association between fecal shedding and gastrointestinal symptoms and to clarify the clinical usefulness testing rectal swabs.We enrolled ten adult patients hospitalized with symptomatic coronavirus disease 2019 (COVID-19). Respiratory and stool specimens were collected by physicians. The presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was confirmed using real-time reverse-transcription polymerase chain reaction. All ten patients had respiratory symptoms, six had diarrhea, and seven were positive for SARS-CoV-2 on rectal swabs. The viral loads in the respiratory specimens was higher than those in the rectal specimens, and no rectal specimens were positive after the respiratory specimens became negative. There was no association between gastrointestinal symptoms, pneumonia, severity, and rectal viral load. Rectal swabs may play a role in detecting SARS-CoV-2 in individuals with suspected COVID-19, regardless of gastrointestinal symptoms.

Current laboratory diagnosis of coronavirus disease 2019

Coronavirus disease 2019 (COVID-19) emerged in December 2019 in Wuhan, China; it has since caused a pandemic, with more than 10,000 confirmed cases (> 800,000 tests) in Korea as of May 2020. Real-time reverse transcription polymerase chain reaction (RT-PCR) is currently the most commonly used method for the diagnosis of COVID-19 worldwide. The Korean Society for Laboratory Medicine and Korea Centers for Disease Prevention and Control regularly update the guidelines for COVID-19 diagnosis. Emergency use authorization for some laboratory diagnostic kits has been granted, enabling the timely diagnosis and treatment of COVID-19, and the isolation of infected patients. Due to the collective efforts of the government, medical professionals, local authorities, and the public, Korea’s response to the COVID-19 outbreak has been accepted widely as a model. Here, we summarize the currently available laboratory tests for COVID-19 diagnosis. Although RT-PCR tests are used widely to confirm COVID-19, antibody tests could provide information about immune responses to the virus.

Analysis of hematologic parameters of donors, patients, and granulocyte concentrates to predict successful granulocyte transfusion

BACKGROUND: Granulocyte transfusion (GTx) is performed as a supportive therapy in severe neutropenic patients caused by various conditions. The study aimed to analyze the hematologic parameters of donors, patients, and granulocyte concentrates to predict successful GTx. METHODS: This study was performed in 281 donors, with their granulocyte concentrates being collected through apheresis, and in 54 severe neutropenic patients who had various hematologic diseases. Complete blood cell counts of donors pre- and post-apheresis, granulocyte concentrates, and patients pre- and post-GTx were analyzed. Patients were divided into two groups according to survival at discharge (Group S, survival; Group D, dead) to compare various factors including age, infection status, pre- and post-GTx total white blood cell counts (TWBCC) and absolute neutrophil counts (ANC), total number of GTx, infused TWBCC and ANC per weight, and use of G-CSF during therapy. RESULTS: Overall data of patients showed that both TWBCC and ANC were significantly increased after GTx (median values at pre-GTx, TWBCC=0.40×109/L, ANC=0.14×109/L; post-GTx, TWBCC=0.57×109/L, ANC=0.29×109/L, both P<0.0001). After GTx, Group S (N=25) showed significantly higher TWBCC and ANC than Group D (N=29) (P=0.01 and P=0.04, respectively). Using different cutoff levels, post-GTx TWBCC greater than 0.5×109/L showed statistically significant difference between the two groups (P<0.01). None of the other factors showed statistically significant differences. CONCLUSION: The TWBCC and ANC after GTx were significant factors to predict patients' outcome. Therefore, follow-up of those two parameters may be helpful to select or consider other therapeutic modalities including additional GTx.

Comparison of Six Commercial Diagnostic Tests for the Detection of Dengue Virus Non-Structural-1 Antigen and IgM/IgG Antibodies

ELISAs and rapid diagnostic tests (RDTs) are widely used for diagnosing dengue virus (DENV) infection. Using 138 single blood samples, we compared the ability to detect non-structural (NS)-1 antigen and anti-DENV IgM/IgG antibodies among (1) DENV Detect NS1 ELISA, DENV Detect IgM capture ELISA and DENV Detect IgG ELISA (InBios International, Inc.); (2) Anti-Dengue virus IgM Human ELISA and Anti-Dengue virus IgG Human ELISA (Abcam); (3) Dengue virus NS1 ELISA, Anti-Dengue virus ELISA (IgM) and Anti-Dengue virus ELISA (IgG) (Euroimmun); (4) Asan Easy Test Dengue NS1 Ag 100 and Asan Easy Test Dengue IgG/IgM (Asan Pharm); (5) SD BIOLINE Dengue Duo (Standard Diagnostics); and (6) Ichroma Dengue NS1 and Ichroma Dengue IgG/IgM (Boditech Med). For NS1 antigen detection, InBios and Euroimmun showed higher sensitivities (100%) than the RDTs (42.9–64.3%). All tests demonstrated variable sensitivities for IgM (38.1–90.5%) and IgG (65.7–100.0%). InBios and Boditech Med demonstrated higher sensitivity (95.6% and 88.2%, respectively) than the other tests for combined NS1 antigen and IgM antibody. Five NS1 antigen tests had good agreement (92.8–98.6%) without showing positivity for chikungunya. However, all IgG tests demonstrated potential false-positivity with variable ranges. Clinical laboratories should note performance variations across tests and potential cross-reactivity.

Evaluation of Hemoglobin Trigger and Appropriateness of Perioperative Red Cell Transfusion in Surgical Departments / 대한수혈학회지

BACKGROUND: Red blood cell (RBC) transfusion is an essential practice during surgery to accommodate for bleeding. As such, there are efforts being made to allow for a safe and appropriate transfusion due to shortages of blood components and to minimize transfusion-related adverse reactions. However, a conventional transfusion decision with relatively high hemoglobin (Hb) threshold is still performed in clinical setting. In this study, we investigated the threshold of Hblevel and appropriateness of RBC transfusion in patients receiving perioperative RBC transfusion in surgical departments. METHODS: We investigated the pre-transfusion Hb level of 1,379 patients (2,170 episodes) receiving perioperative RBC transfusion in five surgical departments, including cardiothoracic surgery (CS), general surgery (GS), neurosurgery (NS), obstetrics and gynecology (OBGY), and orthopedics (OS), between June 2017 and March 2018. The appropriateness of transfusion was evaluated with two criteria: 1) pretransfusion Hb level ≤10 g/dL and 2) posttransfusion Hb level ≤10 g/dL. RESULTS: The median pretransfusion Hb level was 8.5 g/dL (interquartile range 7.7~9.4); that of each department was as follows: 8.6 g/dL (7.9~9.2) in CS, 7.9 g/dL (7.3~8.6) in GS, 9.1 g/dL (8.5~9.8) in NS, 8.5 g/dL (7.7~9.8) in OBGY, and 8.7 g/dL (7.9~9.7) in OS. With a criteria of pretransfusion of Hb level ≤10 g/dL, 85.4% of total episodes were appropriate. With criteria of post-transfusion of Hb level ≤10 g/dL, 44.7% were appropriate. CONCLUSION: This study presents a fundamental data observing the trend of RBC transfusion in a single institution. A significant proportion of inappropriate RBC transfusion are still being conducted in surgical setting. Continuous and effective education of clinicians and implementation of monitoring systems to assess the appropriateness of RBC transfusion may be necessary.

Comparison of Four Automated Carcinoembryonic Antigen Immunoassays: ADVIA Centaur XP, ARCHITECT I2000sr, Elecsys E170, and Unicel Dxi800

BACKGROUND: Carcinoembryonic antigen (CEA) is one of the tumor markers available for evaluating disease progression status after initial therapy and monitoring subsequent treatment modalities in colorectal, gastrointestinal, lung, and breast carcinoma. We evaluated the correlations and differences between widely used, automated CEA immunoassays at four different medical laboratories. METHODS: In total, 393 serum samples with CEA ranging from 3.0 to 1,000 ng/mL were analyzed on ADVIA Centaur XP (Siemens Diagnostics, Tarrytown, NY, USA), ARCHITECT i2000sr (Abbott Diagnostics, Abbott Park, IL, USA), Elecsys E170 (Roche Diagnostics, Indianapolis, IN, USA), and Unicel DxI800 (Beckman Coulter, Fullerton, CA, USA), and the results were compared. Deming regression, Passing-Bablok regression, and Bland-Altman analyses were performed to evaluate the data correlation and % differences among these assays. RESULTS: Deming regression analysis of data from Elecsys E170 and UniCel DxI800 showed good correlation (y=3.1615+0.8970x). According to Bland-Altman plot, no statistically significant bias (−1.78 ng/mL [95% confidence interval: −4.02 to 0.46]) was observed between Elecsys E170 and UniCel DxI800. However, the relative differences of CEA concentrations between assays exceeded the acceptable limit of 30%. Regarding the agreement of positivity with cut-off value 5.0 ng/mL, ARCHITECT i2000sr and Elecsys E170 showed the highest agreement (95.2%), whereas ADVIA Centaur XP and ARCHITECT i2000sr showed the lowest agreement (70.7%). CONCLUSIONS: Agreements between automated CEA immunoassays are variable, and individual CEA concentrations may differ significantly between assays. Standardization of serum CEA concentrations and further harmonization are needed.

Effective sickle hemoglobin reduction by automated red cell exchange using Spectra Optia in three Emirati patients with sickle cell disease before allogeneic hematopoietic stem cell transplantation

No abstract available.

Human Leukocyte Antigen-C Genotype and Killer Immunoglobulin-like Receptor-Ligand Matching in Korean Living Donor Liver Transplantation

BACKGROUND: The interaction between killer immunoglobulin-like receptors (KIRs) and HLA class I regulates natural killer (NK) cell cytotoxicity and function. The impact of NK cell alloreactivity through KIR in liver transplantation remains unelucidated. Since the frequency of HLA-C and KIR genotypes show ethnic differences, we assessed the impact of HLA-C, KIR genotype, or KIR-ligand mismatch on the allograft outcome of Korean liver allografts. METHODS: One hundred eighty-two living donor liver transplant patients were studied. Thirty-five patients (19.2%) had biopsy-confirmed acute rejection (AR), and eighteen (9.9%) had graft failure. The HLA-C compatibility, KIR genotypes, ligand-ligand, and KIR-ligand matching was retrospectively investigated for association with allograft outcomes. RESULTS: Homozygous C1 ligands were predominant in both patients and donors, and frequency of the HLA-C2 allele in Koreans was lower than that in other ethnic groups. Despite the significantly lower frequency of the HLA-C2 genotype in Koreans, donors with at least one HLA-C2 allele showed higher rates of AR than donors with no HLA-C2 alleles (29.2% vs 15.7%, P=0.0423). Although KIR genotypes also showed ethnic differences, KIR genotypes and the number of activating KIR/inhibitory KIR were not associated with the allograft outcome. KIR-ligand mismatch was expected in 31.6% of Korean liver transplants and had no impact on AR or graft survival. CONCLUSIONS: This study could not confirm the clinical impact of KIR genotypes and KIR-ligand mismatch. However, we demonstrated that the presence of HLA-C2 allele in the donor influenced AR of Korean liver allografts.

Development and Performance Evaluation of External Quality Controls for Allergen-Specific Immunoglobulin E Tests

BACKGROUND: Many companies have developed different methods and products for allergen-specific immunoglobulin E (IgE) tests. Because there is no standardised reference method, external quality assessment (EQA) is important for allergen-specific IgE test to ensure the comparability and reliability of the results from different laboratories. We prepared specimens for EQA of allergen-specific IgE tests and evaluated their stability. METHODS: Four pooled sera with 24 selected allergen-specific IgE levels were prepared and stored at −80℃. The stability of allergen-specific IgE levels was assessed on days 1, 7, and 14 at −20℃, 2℃ to 8℃, and 20℃ to 25℃, and then after 3 months at −80℃. Mock proficiency tests were performed with the four sets of prepared external quality controls for six laboratories, using the commercial multiple allergen simultaneous test (MAST) methodology. RESULTS: About 150 specimens (650 µL each) for EQA were prepared; randomly selected specimens showed similar IgE levels for the 24 allergens (±1 class). The levels of allergen-specific IgE remained stable throughout the study period (P>0.05). Although mock survey results from six laboratories using four MAST assays revealed some variability with a difference (2–3 class), no consistent differences were observed through the allergens or MAST methods. Qualitative results from the mock survey showed 85.4% (cut-off of class 1) and 81.3% (cut-off of class 2) concordance with the results from ImmunoCAP (Phadia, Sweden). CONCLUSIONS: The pooled sera prepared for allergen-specific IgE tests might be adequate and useful for EQA.

Four Cases of Chronic Myelogenous Leukemia in Mixed Phenotype Blast Phase at Initial Presentation Mimicking Mixed Phenotype Acute Leukemia with t(9;22)

No abstract available.

Utility of a multiplex reverse transcriptase-polymerase chain reaction assay (HemaVision) in the evaluation of genetic abnormalities in Korean children with acute leukemia: a single institution study / 소아과

PURPOSE: In children with acute leukemia, bone marrow genetic abnormalities (GA) have prognostic significance, and may be the basis for minimal residual disease monitoring. Since April 2007, we have used a multiplex reverse transcriptase-polymerase chain reaction tool (HemaVision) to detect of GA. METHODS: In this study, we reviewed the results of HemaVision screening in 270 children with acute leukemia, newly diagnosed at The Catholic University of Korea from April 2007 to December 2011, and compared the results with those of fluorescence in situ hybridization (FISH), and G-band karyotyping. RESULTS: Among the 270 children (153 males, 117 females), 187 acute lymphoblastic leukemia and 74 acute myeloid leukemia patients were identified. Overall, GA was detected in 230 patients (85.2%). HemaVision, FISH, and G-band karyotyping identified GA in 125 (46.3%), 126 (46.7%), and 215 patients (79.6%), respectively. TEL-AML1 (20.9%, 39/187) and AML1-ETO (27%, 20/74) were the most common GA in ALL and AML, respectively. Overall sensitivity of HemaVision was 98.4%, with false-negative results in 2 instances: 1 each for TEL-AML1 and MLL-AF4. An aggregate of diseasesspecific FISH showed 100% sensitivity in detection of GA covered by HemaVision for actual probes utilized. G-band karyotype revealed GA other than those covered by HemaVison screening in 133 patients (49.3%). Except for hyperdiplody and hypodiploidy, recurrent GA as defined by the World Health Organizationthat were not screened by HemaVision, were absent in the karyotype. CONCLUSION: HemaVision, supported by an aggregate of FISH tests for important translocations, may allow for accurate diagnosis of GA in Korean children with acute leukemia.

Prevalence of p16 Methylation and Prognostic Factors in Plasma Cell Myeloma at a Single Institution in Korea

BACKGROUND: The primary purpose of this study was to investigate the prevalence and characteristics of p16 methylation and determine the prognostic implications of the clinical data, hematologic data, and p16 methylation changes in plasma cell myeloma (PCM). METHODS: We reviewed clinical characteristics and results of laboratory tests and investigated the response to combination chemotherapy and survival time. DNA methylation of the p16 gene was tested by methylation-specific PCR. Clinical significance was evaluated. RESULTS: A total of 103 patients were enrolled in this study. The median patient age was 59.0 yr at diagnosis and the male to female ratio was 1.15:1. According to the International Staging System (ISS), patients were diagnosed as stage: I (N=17, 16.5%), II (N=41, 39.8%), III (N=39, 37.9%), or not classified (N=6). Forty-five (43.7%) patients and 36 (35.0%) patients showed abnormal karyotype and complex karyotype, respectively, on the chromosome study. The p16 methylation was observed in 39 (37.9%) of 103 patients, but there was no significant association between p16 methylation status and other clinical or laboratory factors and survival outcome. Male gender, albumin, and complex karyotype were independent prognostic factors for overall survival according to multivariate analysis (P<0.05). CONCLUSIONS: The male gender, low serum albumin level, and complex karyotype were independent poor prognostic factors for PCM. p16 methylation was relatively common in PCM, but did not influence the survival outcome.

Impact of Genetic Abnormalities on the Prognoses and Clinical Parameters of Patients with Multiple Myeloma

BACKGROUND: We reviewed patients with multiple myeloma (MM) in order to assess the incidence of genetic abnormalities and their associations with clinical parameters, risk groups, and prognosis. METHODS: A total of 130 patients with MM were enrolled. The incidences of genetic abnormalities were determined in all patients. The relationships of the genetic abnormalities and clinical parameters were investigated. In addition, a survival analysis was performed. RESULTS: Abnormal karyotypes were detected in 42.3% (N=55) of the patients, and this was increased to 63.1% (N=82) after including the results determined with interphase FISH. Hypodiploidy was observed in 7.7% (N=10) of the patients, and all were included in the group with complex karyotypes (30.8%, N=40). The 14q32 rearrangements were detected in 29.2% (N=38) of the patients, and these most commonly included t(11;14), which was followed by t(4;14) and t(14;16) (16.2%, 11.5%, and 0.8%, respectively). Abnormal karyotypes and complex karyotypes were associated with disease progression markers, including low hemoglobin levels, low platelet counts, high plasma cell burden, high beta2-microglobulin, and high international staging system stages. A high free light chain (FLC) ratio and FLC difference were associated with abnormal karyotypes, complex karyotypes, and higher plasma cell burden. Hypodiploidy and low platelet counts were significant independent prognostic factors and were more important in patient outcome than any single abnormality. CONCLUSIONS: Genetic abnormalities were associated with disease progression markers and prognosis of MM patients.

Correction of Pseudoreticulocytosis in Leukocytosis Samples Using the Sysmex XE-2100 Analyzer Depends on the Type and Number of White Blood Cells

BACKGROUND: The reticulocyte count is a good marker of erythropoietic activity of the bone marrow. In the mid-1990s, automated flow cytometric analysis replaced microscopy for the quantification of reticulocytes. Leukocytosis cases with an erroneously high reticulocyte count and a high immature reticulocyte fraction (IRF) have been reported. In this study, we analyzed reticulocyte counts in leukocytosis samples, in an effort to identify a correction method. METHODS: The study comprised of 21 samples from 16 leukocytosis patients. Results of reticulocyte analyses obtained using a XE-2100 hematology analyzer (Sysmex, Japan) were compared with those obtained using the supravital staining technique, which is a reference method. If the samples showed erroneously high reticulocyte counts and IRF, they were reanalyzed after serial dilution with isotonic solution. RESULTS: Five samples from 4 patients showed erroneously elevated reticulocyte counts and/or IRF on the XE-2100 analyzer. They displayed abnormal reticulocyte scattergrams, with 4 of 5 cases indicated by a flag. The white blood cell (WBC) fractions overlapped with the reticulocyte regions, especially with the IRF. Diagnoses and blast counts were variable when such errors occurred; WBC counts varied from 218.19x10(9)/L to 725.14x10(9)/L. The errors were corrected by simple dilution with isotonic solution. However, the corrective WBC counts differed according to individual cases. CONCLUSIONS: When leukocytosis samples exhibit an abnormal reticulocyte scattergram with a flag, or an abnormally high IRF, we recommend the dilution of the sample with isotonic solution to a WBC count of about 100.00x10(9)/L, followed by reanalysis of the reticulocyte count and reticulocyte scattergram.

What should we consider in mixed chimerism after hematopoietic stem cell transplantation? / 대한혈액학회지

No abstract available.

Reliable, Accurate Determination of the Leukocyte Differential of Leukopenic Samples by Using Hematoflow Method / 대한진단검사의학회지

BACKGROUND: Hematology analyzers may ineffectively recognize abnormal cells, and manual differential counts may be imprecise for leukopenic samples. We evaluated the efficacy of the Hematoflow method for determining the leukocyte differential in leukopenic samples and compared this method with the manual differential method. METHODS: We selected 249 blood samples from 167 patients with leukopenia (WBC counts, 500-2,000/microL) for analysis in this study. The EDTA-anticoagulated blood samples were analyzed using an automatic blood cell counter (DxH800; Beckman Coulter, USA) and flow cytometry (FC 500; Beckman Coulter) by using Cytodiff reagent and analysis software (Beckman Coulter). Hematoflow results were selected or calculated from DxH800 and Cytodiff results. Two trained pathologists performed a manual differential count by counting 50-100 cells. RESULTS: The precision of the Hematoflow method was superior to that of the manual method in counting 5 leukocyte subpopulations, immature granulocytes (IGs), and blasts. Blasts were detected in all 45 cases (100%) by Hematoflow. The correlation of the Cytodiff blast count to the reference count was high (r = 0.8325). For all other cell populations, the correlation of the Hematoflow results with the reference count was stronger than that of the other manual counts with the reference count. CONCLUSIONS: The Hematoflow differential counting method is more reproducible and sensitive than manual counting, and is relatively easy to perform. In particular, this method detected leukemic blasts more sensitively than manual differential counts. The Hematoflow method is a very useful supplement to automated cell counting.

Reliable, Accurate Determination of the Leukocyte Differential of Leukopenic Samples by Using Hematoflow Method / 대한진단검사의학회지

BACKGROUND: Hematology analyzers may ineffectively recognize abnormal cells, and manual differential counts may be imprecise for leukopenic samples. We evaluated the efficacy of the Hematoflow method for determining the leukocyte differential in leukopenic samples and compared this method with the manual differential method. METHODS: We selected 249 blood samples from 167 patients with leukopenia (WBC counts, 500-2,000/microL) for analysis in this study. The EDTA-anticoagulated blood samples were analyzed using an automatic blood cell counter (DxH800; Beckman Coulter, USA) and flow cytometry (FC 500; Beckman Coulter) by using Cytodiff reagent and analysis software (Beckman Coulter). Hematoflow results were selected or calculated from DxH800 and Cytodiff results. Two trained pathologists performed a manual differential count by counting 50-100 cells. RESULTS: The precision of the Hematoflow method was superior to that of the manual method in counting 5 leukocyte subpopulations, immature granulocytes (IGs), and blasts. Blasts were detected in all 45 cases (100%) by Hematoflow. The correlation of the Cytodiff blast count to the reference count was high (r = 0.8325). For all other cell populations, the correlation of the Hematoflow results with the reference count was stronger than that of the other manual counts with the reference count. CONCLUSIONS: The Hematoflow differential counting method is more reproducible and sensitive than manual counting, and is relatively easy to perform. In particular, this method detected leukemic blasts more sensitively than manual differential counts. The Hematoflow method is a very useful supplement to automated cell counting.