Inflammation modifies the platelet reactivity among thrombocytopenia patients undergoing percutaneous coronary intervention.

Percutaneous coronary intervention (PCI) patients combined with thrombocytopenia (TP) are usually considered to be at low ischemic risk, receiving less proper antiplatelet therapy. However, recent studies reported a paradoxical phenomenon that PCI patients with TP were prone to experience thrombotic events, while the mechanisms and future treatment remain unclear. We aim to investigate whether inflammation modifies platelet reactivity among these patients. Consecutive 10 724 patients undergoing PCI in Fuwai Hospital were enrolled throughout 2013. High-sensitivity C-reactive protein (hsCRP) ≥2 mg/L was considered inflammatory status. TP was defined as platelet count <150×109/L. High on-treatment platelet reactivity (HTPR) was defined as adenosine diphosphate-induced platelet maximum amplitude of thromboelastogram >47mm. Among 6617 patients finally included, 879 (13.3%) presented with TP. Multivariate logistic regression demonstrated that patients with TP were associated with a lower risk of HTPR (odds ratio [OR] 0.64, 95% confidence interval [CI] 0.53-0.76) than those without TP in the overall cohort. In further analysis, among hsCRP <2 mg/L group, patients with TP exhibited a decreased risk of HTPR (OR 0.53, 95% CI 0.41-0.68); however, in hsCRP ≥2mg/L group, TP patients had a similar risk of HTPR as those without TP (OR 0.83, 95% CI 0.63-1.08). Additionally, these results remain consistent across subgroups, including patients presenting with acute coronary syndrome and chronic coronary syndrome. Inflammation modified the platelet reactivity of PCI patients with TP, providing new insights into the mechanisms of the increased thrombotic risk. Future management for this special population should pay more attention to inflammation status and timely adjustment of antiplatelet therapy in TP patients with inflammation.

What is the context? Recent studies reported a paradoxical phenomenon that percutaneous coronary intervention (PCI) patients with thrombocytopenia (TP) were prone to experience thrombotic events. The potential mechanisms underlying the increased thrombotic risk and how to manage antiplatelet therapy in PCI patients with TP remain unclear.Growing attention has been paid to immunothrombosis. Inflammation is closely associated with high-on treatment platelet reactivity (HTPR) and thrombotic risk.HTPR is an independent risk factor of thrombosis and can provide information for guiding antiplatelet therapy.What is new? This prospective cohort study enrolled 10 724 patients undergoing PCI in Fuwai Hospital (National Center for Cardiovascular Diseases, Beijing, China), with HTPR risk being the study endpoint of interest.We first reported that inflammation significantly modified the platelet reactivity of PCI patients with TP.When hsCRP level <2 mg/L, PCI patients with TP had a decreased risk of HTPR. However, when hsCRP ≥2 mg/L, TP patients had similar HTPR risk as those without TP.HsCRP levels could modify the relationship between TP and HTPR risks both in patients with acute coronary syndrome and chronic coronary syndrome.What is the impact? These results provide insights into potential mechanisms of the increased thrombotic risk in PCI patients with TP. Specifically, inflammation might be involved in the thrombotic risk of PCI patients with TP by modifying the platelet reactivity.As for future management, personalized antiplatelet therapy should be administrated to TP patients with inflammation status.

Spurious High Platelet Count without PLT Flag(S) in a Patient with Severe Aplastic Anaemia.

BACKGROUND: Platelet (PLT) count is one of the most important parameters of automated hematology, as spurious PLT reports could affect medical judgement and bring significant risks. In most cases, spurious PLT will not be reported for review criteria, which will be triggered by abnormal PLT histograms and PLT flag(s). Here, we present a case of severe aplastic anemia after hematopoietic stem cell transplantation with spurious high platelet count with normal histogram and no PLT flag(s). METHODS: The electrical impedance channel (PLT-I) and the fluorescence channel (PLT-F) of Sysmex XN-series hematology analyzer was used to obtain PLT results. Then, the sample was retested by another hematology analyzer MINDRAY BC-7500 [NR] CRP, and incubation was performed to rule out cryoglobulin interference. Furthermore, a microscope was used to estimate the PLT count by the ratio of platelets to red blood cells and observe the morphology of cells. RESULTS: Both PLT-I and PLT-F test results were spuriously high, and microscopically assessed platelet counts were relatively reliable. The observed spiny cells and ghost cells caused by hemolysis may have contributed to the inaccuracy of instrumental counting in this case. CONCLUSIONS: For special hematologic patients, PLT-I with flags may not be sufficient for screening purposes and PLT-F is not always accurate. Multiple testing methods including manual microscopy are needed.

Can platelet activation markers predict preeclampsia and/or its severity?

OBJECTIVE: This study aimed to evaluate the value of platelet activation markers in predicting preeclampsia and its severity. Preeclampsia is a serious pregnancy complication that affects 3-5% of pregnancies and can lead to significant morbidity and mortality for both the mother and the fetus. METHODS: The study included 99 patients diagnosed with preeclampsia and 60 healthy pregnant women as a control group. Platelet activation markers such as mean platelet volume (MPV), platelet distribution width (PDW), platelet count, and plateletcrit were evaluated along with other clinical parameters. RESULTS: The results of the study showed that platelet activation markers, particularly PDW and MPV, are valuable in the diagnosis and follow-up of preeclampsia. However, they are not sufficient to predict the severity of the disease. CONCLUSION: The study suggests that platelet activation markers could aid in predicting, diagnosing, and managing preeclampsia. However, further research is needed to determine the role of these markers in predicting the severity of the disease. The findings of this study could contribute to the development of more effective strategies for the prevention and management of preeclampsia, which could ultimately improve maternal and fetal outcomes.

OBJETIVO: El estudio tuvo como objetivo determinar el valor de los marcadores de activación plaquetaria en la predicción de la preeclampsia y su gravedad. MÉTODO: Se incluyeron 99 pacientes diagnosticadas con preeclampsia, incluyendo 36 casos graves, y un grupo control de 60 mujeres embarazadas sanas. Se evaluaron diversas variables, como el volumen plaquetario medio, el recuento de plaquetas, el hematocrito plaquetario y la amplitud de distribución plaquetaria. RESULTADOS: Los resultados mostraron que el volumen plaquetario medio y la amplitud de distribución plaquetaria son parámetros valiosos en el diagnóstico y seguimiento de la preeclampsia, aunque no son suficientes para predecir su gravedad. El análisis estadístico reveló que la edad, el volumen plaquetario medio, la amplitud de distribución plaquetaria, la semana de gestación y los puntajes de Apgar al primer y quinto minuto fueron significativamente diferentes en el grupo de preeclampsia en comparación con el grupo control. CONCLUSIONES: En conclusión, estos resultados sugieren que los marcadores de activación plaquetaria pueden ser útiles para el diagnóstico y seguimiento de la preeclampsia, y que el volumen plaquetario medio y la amplitud de distribución plaquetaria, por ser parámetros económicos y accesibles, podrían ayudar a predecir, diagnosticar y manejar esta complicación durante el embarazo.

Marked Underestimation of Platelet Count and a Characteristic Platelet Histogram as Clues to MYH9-Related Disorders.

BACKGROUND: The rapid development of automatic blood cell analyzers has greatly optimized complete blood count results. However, erroneous results relevant to automatic blood cell analyzers still exist. Pseudothrombocytopenia can be observed in both cases of anticoagulant-induced platelet aggregation, and the presence of large and giant platelets. METHODS: A rare case of a MYH9-related disorder, in which marked underestimation of platelet count was led by large and giant platelets using the impedance count by an automated hematology analyzer. Moreover, lancet-shaped and Dohle body-like cytoplasmic inclusions were detected in almost all white blood cells of the patient. RESULTS: The platelet count was done by an optical platelet counter or a fluorescence platelet counter, and peripheral blood smear was evaluated. In addition, the diagnosis of MYH9-related disorder was established by the molecular findings. CONCLUSIONS: Identification of the peripheral blood smear and familial history will eliminate the need for further laboratory testing and bone marrow examination.

Pseudothrombocytosis Associated with Heatstroke.

BACKGROUND: In several situations, spurious results are observed in the use of hematology analyzers including pseudothrombocytosis caused by part of the cytoplasm of abnormal cells which was reported in leukemic blasts, monoblasts, or lymphoblasts. METHODS AND RESULTS: Here, we report a rare case of pseudothrombocytosis caused by mature leukocyte fragments associated with heatstroke. It was identified by the peripheral blood smear and obvious difference between the PLT-F (fluorescence) and I (impedance) channel. CONCLUSIONS: Observation of peripheral blood smears and determination on the PLT-F channel can identify this interference caused by leukocyte fragments in heatstroke.

Micro-Red Blood Cell, Fragmented Red Blood Cell, Platelet Distribution Width, Mean Platelet Volume, and Platelet-Large Cell Ratio on Sysmex XN Series Hematology Analyzers Can Be Used for the Reflex Test of Impedance Platelet Count in Clinical Practice.

CONTEXT.­: Platelet (PLT) counting with impedance (PLT-I) is widely used but has low specificity. PLT counting with fluorescence (PLT-F), tested by the Sysmex XN series with high specificity, can be a complementary method to PLT-I. OBJECTIVE.­: To identify red blood cell (RBC)- and PLT-related parameters as potential influencing factors for PLT-I and establish PLT reflex test rules with PLT-F. DESIGN.­: We prospectively tested both PLT-I and PLT-F in all 3480 samples. In a development data set of 3000 samples, differences between the reflex and nonreflex groups were compared and influencing factors for PLT-I were identified by logistic regression. The area under the receiver operating characteristic (ROC) curve and cutoff values were obtained by ROC curve analysis. Validation was conducted in the remaining 480 samples (validation data set). RESULTS.­: PLT-F showed comparable results with immunoplatelet counting. In logistic regression, increased micro-RBC absolute count (micro-RBC#), fragmented RBC absolute count (FRC#), PLT distribution width (PDW), mean PLT volume (MPV), PLT-large cell ratio (P-LCR), and immature PLT fraction absolute count (IPF#) were influencing factors for PLT-I. In ROC curve analysis, the cutoff values of micro-RBC#, FRC#, PDW, MPV, and P-LCR were 0.64 × 106/µL, 0.082 × 106/µL, 15.40 fL, 11.15 fL, and 33.95%, respectively. The areas under the ROC curve of micro-RBC# and FRC# were 0.77 and 0.79, respectively. CONCLUSIONS.­: Micro-RBC#, FRC#, PDW, MPV, P-LCR, and IPF# were factors affecting PLT-I. Among them, micro-RBC# and FRC# were the most impactful factors. From our study results, micro-RBC#, FRC#, MPV, PDW, and P-LCR can be used to establish reflex test rules for PLT counting in clinical work.

Performance evaluation of a novel platelet count parameter, hybrid platelet count, on the BC-780 automated hematology analyzer.

OBJECTIVES: Automated hematology analysis is expected to improve the performance of platelet counting. We evaluated the performance of a new platelet counting, hybrid (PLT-H) and also impedance (PLT-I) and optical (PLT-O) on the BC-780 automated hematology analyzer compared to the international reference method (IRM) in blood samples with thrombocytopenic and platelet interference. METHODS: The basic platelet count performance of the BC-780 automated hematology analyzer was evaluated according to the requirements of the Clinical Laboratory and Standards Institute (CLSI) Document H26-A2. Additionally, the thrombocytopenic (low PLT count) blood samples and the platelet interference blood samples including fragmented red blood cells (RBCs), microcytes or small RBCs, and giant platelets were determined with the BC-780 hematology analyzer compared to the IRM. RESULTS: Blank counting and the carry-over contamination rate of platelet count using the BC-780 both met the manufacturers' claim. For both 123 thrombocytopenic and 232 platelet interference blood samples (72 fragmented RBCs, 91 microcytes and 51 giant platelets), all three platelet counting methods exhibited high comparability with the IRM (the lowest correlation (r)=0.916). Interestingly, the comparability of PLT-H (r=0.928-0.986) with the IRM was better than that of PLT-I (r=0.916-0.979). CONCLUSIONS: The performance of PLT-H in the BC-780 met the manufacturer's specifications. PLT-H exhibits better reproducibility than did PLT-I, correlates well with the PLT-O for thrombocytopenic samples and demonstrates good anti-interference ability. PLT-H counting is therefore recommended as a zero-cost alternative platelet counting method for platelet interference samples in clinical settings.

Performance evaluation the new automated Atellica Hema 580 hematology analyzer.

INTRODUCTION: The Atellica Hema (Siemens Healthineers, Tarrytown, NY, USA) is a new generation multi-parameter analyzer for full blood count, 6-part differential and reticulocyte testing by impedance variation and fluorescence flow cytometry. In this study, we verified the whole blood and limited body fluid modes of the Atellica Hema 580. METHODS: We evaluated precision, linearity, carry-over, throughput and performed a method comparison to assess the performance of the Atellica Hema 580. For comparison of the Atellica Hema 580 with the Sysmex XN-1000 (Sysmex, Kobe, Japan), 140 samples from adult and pediatric patients including both normal and abnormal hematology profiles were analyzed in parallel. RESULTS: The Atellica Hema 580 demonstrated acceptable imprecision within the manufacturer's specifications for whole blood and body fluid modes, good linearity for high and low ranges and no significant carryover. The full blood count, differential and reticulocyte correlated well with the Sysmex XN-1000, except for mean cell hemoglobin concentration, basophil and large immature cells. The optical platelet count, reflexed in 34 samples with a platelet count <150 × 109 /l, showed a strong correlation with the fluorescent platelet count on the Sysmex XN-1000. The morphology flagging efficiency was 92% for white blood cells, 95% for red blood cells and 87% for platelets. CONCLUSION: The Atellica Hema 580 showed good analytical performance and workflow efficiency for a wide range of patient samples.

[Effects of Apheresis Platelet Transfusion on PLT, MPV, PDW and PCT].

OBJECTIVE: To investigate the changes of platelet count (PLT), plateletcrit (PCT), mean platelet volume (MPV) and platelet distribution width (PDW) before and after apheresis platelet transfusion, the correlation between the parameters and their clinical significance. METHODS: A total of 38 patients who received apheresis platelet transfusion were selected, their results of blood routine test closest to the time point of apheresis platelet transfusion were consulted from hospital information system and the changes of PLT, PCT, MPV and PDW were compared before and after transfusion. The correlation between above parameters was analyzed. The correlation of body mass index (BMI) with the increased multiple and increased value after platelet infusion was also analyzed. RESULTS: Compared with pre-infusion, PLT and PCT significantly increased (both P <0.001) while MPV and PDW showed no significant difference after apheresis platelet transfusion (P >0.05). The difference of PLT and PCT before and after apheresis platelet transfusion had no correlation with PLT and PCT before transfusion (r =0.002, r =0.001), while the difference of MPV and PDW was negatively correlated with MPV and PDW before transfusion (r =-0.462, r =-0.610). The PLT growth rate was positively correlated with PCT growth rate before and after apheresis platelet transfusion (r =0.819). BMI was positively correlated with the increased multiple of PLT after infusion (r =0.721), but not with the increased value of PLT after infusion (r =0.374). CONCLUSION: Apheresis platelet transfusion can cause platelet parameters change and shows different characteristics. Characteristic changes of platelet parameters and their correlation can be used as reference indices to evaluate the efficacy of apheresis platelet transfusion.

Hematological parameters: is there a difference between those released by the hematological analyzer and to the customer?

OBJECTIVE: This study aimed to compare the hematological parameters released by hematological analyzers with those released in customer reports. METHODS: We conducted a descriptive study in the laboratories of a medium-sized municipality in the state of Minas Gerais registered in the National Register of Health Establishments. Interviews were conducted using a questionnaire to obtain information regarding the parameters released by the analyzers and those available in the customer's report. RESULTS: Sixteen laboratories were evaluated, and none of them released all the parameters obtained from the hematological analyzers to customers. The red blood cell distribution width was released in 88% of the laboratories, atypical lymphocytes in 70%, mean platelet volume in 50%, platelet distribution width and platelet count in 20%. No laboratory released information on reticulocytes, fraction of immature reticulocytes and immature granulocytes, nucleated erythrocyte count, immature platelet fraction and reticulocyte hemoglobin, and large platelet rate. CONCLUSION: All evaluated clinical analysis laboratories had at least one parameter that was not released in the customer's report despite being released by the hematological analyzers. The lack of knowledge on the part of professionals about the clinical importance of each parameter of the complete blood count results in a loss in patient assessment, and it is important to include these parameters in the complete blood count report.

Performance evaluation of PLT-H (hybrid-channel platelet) under various interferences and application studies for platelet transfusion decisions.

The hybrid-channel platelet counting method (PLT-H) is a new platelet counting technique proposed by Mindray of China. In this study, we aimed to evaluate the accuracy of this technique in various situations and its reliability in platelet transfusion decision-making. A total of 378 venous blood samples were tested. Using the immunological PLT counting method recommended by the International Council for Standardization in Hematology as the reference method (PLT-IRM), Passing-Bablok regression and Bland-Altman analysis were performed on the PLT-H results. The anti-interference performance of PLT-H under different interference levels was explored using intergroup comparisons, and confusion matrices were analyzed at various transfusion cutoff values. In the absence of interference, there was a strong correlation between PLT-H and PLT-IRM (r = 0.993, 95% CI: 0.990-0.996). Under various interference conditions, the correlation between PLT-H and PLT-IRM was between 0.963 and 0.992, with an average deviation of -14.56 to -2.02. The performance of PLT-H against interference did not change significantly with increasing levels of small RBCs, large PLTs, and RBC fragments (P = .5704, 0.0832, 0.9893). In low-value samples (PLT <100 × 109/L), the coefficient of variation (CV) for PLT-H was less than 7.6%, regardless of the presence or absence of interfering substances. In addition, there was a high agreement between PLT-H and PLT-IRM (ICC = 0.972). Confusion matrice analysis at each medical decision level showed similarity to methods using the fluorescence channel (PLT-O) and superiority to the impedance channel (PLT-I). Compared with PLT-I, PLT-H has higher accuracy in PLT counting, stronger anti-interference ability, better performance in low-value samples at no extra economic cost and can be more useful for platelet transfusion decision-making. PLT-H is a novel method for platelet counting that offers higher accuracy, providing physicians with the ability to make better medical decisions, particularly in cases where values are low, or interference is present. As it does not require additional reagents, it is highly likely to replace PLT-I and become the mainstream method for platelet counting in the future.

The diagnostic accuracy of mean platelet volume in differentiating immune thrombocytopenic purpura from hypo-productive thrombocytopenia: A systematic review and meta-analysis.

BACKGROUND: Thrombocytopenia is defined as a decreased number of platelets in the circulating blood as a result of hypo-proliferation in marrow or peripheral destruction of platelets. Several diagnostic methods have been proposed to discriminate the underline cause of thrombocytopenia. Recent studies showed that mean platelet volume (MPV) could be used for differential diagnosis of immune thrombocytopenic purpura (ITP). Thus, we aimed to investigate the diagnostic accuracy of MPV for differential diagnosis of ITP from hypo-productive thrombocytopenia. METHODS: This study was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines (PRISMA). The study protocol was registered on PROSPERO with the reference number CRD42023447789. Relevant published studies that were published up to April 10, 2023, in peer-reviewed journals were searched on electronic different databases. The methodological quality of the included studies was appraised using the quality assessment of diagnostic accuracy studies 2 (QADAS-2) tool. The pooled weight mean difference (WMD) of MPV between the ITP group and hypo-productive group was analyzed using a random-effects model meta-analysis. Relevant data were extracted using a Microsoft Excel spreadsheet and analyzed using STATA 11.0 and Meta-disc 1.4 software. Publication bias was evaluated using Deek's funnel plot asymmetry test. RESULTS: A total of 14 articles were included in this systematic review and meta-analysis. The comparison of MPV between groups revealed that the pooled mean value of MPV increased significantly in ITP patients compared to patients with hypo-productive thrombocytopenia (WMD = 2.03; 95% CI, 1.38-2.69). The pooled sensitivity and specificity of MPV in differentiating ITP from hypo-productive thrombocytopenia were 76.0% (95% CI: 71.0%, 80.0%) and 79.0% (95% CI: 75.0%, 83.0%), respectively. The summary positive likelihood ratio (PLR) and negative likelihood ratio (NLR)using the random effects model were 3.89 (95% CI: 2.49, 6.10) and 0.29 (95% CI: 0.18, 0.46), respectively. CONCLUSION: MPV can be used to discriminate ITP from hypo-productive thrombocytopenia. It can possess large advantages as it is noninvasive, simple, quick, inexpensive, easy to perform, reliable, and routinely generated by automated cell counters.

Risk factors for thrombocytopenia in patients receiving linezolid therapy: a systematic review and meta-analysis.

PURPOSE: The incidence of linezolid-induced thrombocytopenia (LIT) has been reported to vary widely across studies. We performed a meta-analysis to identify the risk factors for thrombocytopenia among patients who received linezolid treatment. METHODS: The PubMed, Embase and Cochrane Library databases were searched from inception to November 2022 to identify eligible studies. Data on the potential predictors of incidence in LIT were pooled using a random effects model. Sensitivity analyses were performed to determine the robustness of the results when significant heterogeneity was observed. RESULTS: Forty observational studies involving 6454 patients treated with linezolid were included in the analysis. LIT was estimated to occur in 37% of patients. The following important factors were associated with the incidence of LIT: advanced age, body mass index, concurrent renal impairment or liver disease, abnormal laboratory parameters (including white blood cell count, serum creatinine, baseline platelet count, albumin, creatinine clearance rate, and estimated glomerular filtration rate), treatment duration and renal replacement therapy. CONCLUSIONS: A variety of risk factors related to the occurrence of LIT were revealed in our analysis. Early identification of these factors could help patients improve clinical outcomes.

Revisión del intervalo de referencia del recuento plaquetario: ¿son adecuados los valores que estamos utilizando? / Review of the platelet count reference range: are the values we are using appropriate?

Los intervalos de referencia (IR) dependen de la población y de las características metrológicas del procedimiento de medida utilizado. A pesar de las recomendaciones internacionales, son pocos los laboratorios que establecen sus propios IR para cada magnitud por la dificultad para conseguir voluntarios de referencia y el elevado costo económico asociado. La International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) acepta la adopción de IR bibliográficos o su cálculo por métodos indirectos dado su bajo costo y fácil obtención. Existen varias fuentes confiables de IR bibliográficos para el hemograma. No obstante, para el recuento plaquetario, es una práctica común de los laboratorios emplear el rango de valores de 150-450.109 /L independiente de la metodología utilizada y grupo etario. El objetivo de este trabajo fue revisar los IR bibliográficos disponibles para el recuento plaquetario y estimarlo empleando el método indirecto de Hoffmann a partir de nuestra población. Los métodos indirectos se basan en aplicar criterios de exclusión y cálculos matemáticos sobre los resultados de una base de datos de laboratorio. Nuestros IR para el recuento plaquetario se comparan con los bibliográficos, que han sido establecidos por técnicas de muestreo directo. Por este motivo y dado que no existen estudios poblacionales que lo avalen, sería apropiado reemplazar el rango de 150-450.109 / L. Estos límites podrían seguir empleándose como puntos de corte o niveles de decisión médica para definir, según la clínica y otros resultados de laboratorio, los pacientes que ameritan un seguimiento posterior (AU)

Reference ranges (RR) depend on the population and the metrological characteristics of the measurement procedure used. Despite international recommendations, few laboratories establish their own RRs for each magnitude because of the difficulty in obtaining reference volunteers and the associated high economic cost. The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) accepts the use of literaturebased RRs or RRs calculated by indirect methods because of their low cost and easy collection. There are several reliable sources of literature-based RRs for the Cell Blood Count. However, for platelet count, it is common laboratory practice to use the range of 150-450,109 /L regardless of the methodology used and age group. The aim of this study was to review the available literature regarding RRs for platelet count and to establish it using the indirect Hoffmann method in our population. Indirect methods are based on applying exclusion criteria and mathematical calculations on the results of a laboratory database. Our RRs for platelet counts are compared with those in the literature, which have been established by direct sampling techniques. Therefore, and given that there are no population studies to support these findings, it would be appropriate to replace the 150-450,109 /L range. These limits may continue to be used as cut-off points or medical decision levels to define, according to clinical manifestations and other laboratory results, patients who warrant further follow-up (AU)

Selection of Automated Platelet Counting Methods Based on Mean Platelet Volume (MPV).

BACKGROUND: Impedance-based detection and optic detection with fluorescence are common platelet counting methods used by modern hematology analyzers. There are few studies to compare the accuracy of platelet counts using these methods in case of increased MPV. METHODS: Sixty patients with immune-related thrombocytopenia (IRTP) and 60 healthy controls were included. Platelet counts were obtained by BC-6900 analyzer using impedance detection (PLT-I) and optic detection with fluorescence (PLT-O). Flow cytometry was used as the reference (FCM-ref). RESULTS: The platelet counts in patients using PLT-I were significantly lower than those using PLT-O or FCM-ref by an average of 13.3%. The platelet counts by PLT-O compared to FCM-ref were not statistically significant. MPV inversely affected the platelet counts. When MPV was < 13 fL, platelet counts by all three methods were not statistically different. When MPV was ≥ 13 fL, platelet counts by PLT-I were significantly lower (-15.8%) than those by PLT-O or FCM-ref. Furthermore, when MPV was ≥ 15 fL, platelet counts using PLT-I were further decreased (-23.6%) compared to the counts obtained by PLT-O or FCM-ref. CONCLUSIONS: The platelet counts by PLT-O in patients with IRTP is as accurate as by FCM-ref. When MPV is < 13 fL, platelet counts by all three methods are comparable. However, when MPV is ≥ 13 fL, platelet counts by PLT-I can erroneously decrease by as many as 23.6%. Therefore, in case of IRTP, or any cases when MPV ≥ 13 fL, platelet counts obtained by PLT-I method should be carefully checked by other methods, such as PLT-O to ensure a more accurate platelet count.

An Optimized Method of Collecting Murine Peripheral Blood and Dilution Correction for Accurate Blood Cell Enumeration.

Accurate measurement of whole blood counts from mice is an essential quantitative tool across the fields of vascular cell biology. In particular, the measurement of platelet counts can be challenging as the process relies upon good phlebotomy technique, the inclusion of a sufficient amount of the appropriate anticoagulant, and very often dilution of the sample to meet the sample volume requirements of an automated analyzer. To minimize sample dilution, blood collection tubes pre-coated with the anticoagulant can be used; however, these are expensive and prone to blood clotting issues. Here, we describe a simple dilution correction method that accurately calculates blood-to-anticoagulant dilutions to generate appropriate volumes for automated blood cell analysis while minimizing blood clotting. We also discuss some simple steps that can be incorporated into blood collection methods to avoid artefacts during blood collection. Blood count data analysis involving volume correction and clot exclusion can significantly reduce variable blood cell count values among healthy untreated littermates. It also detects subtle changes in blood cell counts, mainly of platelets and RBCs in experimental settings, which can be masked in the absence of careful and precise volume correction. Blood count analysis with volume correction precisely determines mouse whole blood cell counts for investigators. The decreased variability in cell count values reduces the number of experimental animals required for meaningful analysis. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol: An optimized method of collecting murine peripheral blood and dilution correction for accurate blood cell enumeration.

[Cyclic thrombocytopenia diagnosed by periodic platelet count measurements].

Cyclic thrombocytopenia (CTP) is characterized by periodic platelet count fluctuations and is commonly misdiagnosed as immune thrombocytopenia (ITP) because of their similar clinical characteristics. Here, we present the case of a 74-year-old man with CTP diagnosed by weekly platelet count measurements. The patient initially developed mild bleeding symptoms with a platelet count of 0.8×104/µl. Bone marrow biopsy exhibited reduced megakaryocyte counts, an atypical characteristic of ITP. Weekly follow-up of platelet counts demonstrated an apparent cyclic pattern, resulting in CTP diagnosis. Regular platelet count measurements can help diagnose CTP in thrombocytopenia.

Comparison of platelet count results on the Sysmex XN between citrate or MgSO4 and K2 EDTA anticoagulants.

INTRODUCTION: The aim of this study performed on Sysmex XN is to compare platelet values on citrate and MgSO4 (TBX) in patients with K2EDTA-induced platelet clusters and to identify platelet biases of these matrices compared to K2EDTA. METHODS: Sixty patients with K2EDTA-induced platelet clusters were re-sampled with K2EDTA, citrate and TBX. Platelet results were then compared, and smears were analysed for clumping. Platelet results from 120 patients without K2EDTA-induced platelet clusters were compared between K2 EDTA, citrate, and MgSO4 with impedance and fluorescence modes. Biases from regressions were analysed. RESULTS: Out of the 60 patients with K2EDTA-induced platelet clusters, none showed platelet clusters with MgSO4 whereas 50% still showed clusters with citrate. Among those without platelet clusters on citrate, the mean relative difference between (citrate- MgSO4 )/MgSO4 was -12.7% in impedance and -9.8% in fluorescence. Among the 120 patients without K2EDTA-induced platelet clusters, in fluorescence the mean relative bias with respect to K2EDTA was -2.06% for MgSO4 and -10.3% for Citrate. For the MgSO4 versus K2 EDTA regressions, the maximum absolute values of the 95% CI of the relative biases at 150 × 109 /L (5.45%) and 450 × 109 /L (3.56%) were below the desirable analytical objectives of the EFLM. CONCLUSION: In patients with K2EDTA-induced platelet clusters, MgSO4 is preferable to citrate. MgSO4 provides a bias with XN in fluorescence when compared to EDTA which is within analytical tolerance.

Association between first trimester platelet to lymphocyte ratio and stillbirth.

BACKGROUND: Neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) have been investigated as inflammatory markers of malignancies, cardiovascular and autoimmune diseases. We explored the association between NLR, PRL, measured during pregnancy, and stillbirth (SB). METHODS: We conducted a retrospective case control study at a tertiary hospital center in New York City from May 2015 to July 2018. Cases were defined as SB pregnancies and controls as uncomplicated pregnancies. We calculated NLR and PLR using the complete blood count components routinely collected during prenatal care in the first trimester. The groups were matched by age, parity, body mass index (BMI) and race. We used receiver operating characteristic (ROC) curve analysis to evaluate the association of NLR and PLR to SB. RESULTS: We identified 28 patients with SB pregnancies and matched them with 28 controls. Age, parity, BMI, and race were equally distributed between the groups. The median gestational age of SB was 30 weeks (22-34). In the first trimester PLR was significantly lower in SB cases compared to controls (124.8 vs. 153.4, P=0.044) with an area under the curve (AUC) of 0.65. A PLR value higher than 156.4 accurately excluded SB with a sensitivity of 0.50, specificity of 0.89, positive predictive value of 0.013 and a negative predictive value of 0.998. NLR did not show a significant difference in the first trimester. CONCLUSIONS: A PLR higher than 156.4 in the first trimester appears to reliably exclude the occurrence of SB later during pregnancy. Lower platelet and higher lymphocyte levels may be related to an early inflammatory process. We speculate that pregnancies in which the initial myometrial invasion by the placental cells is dysfunctional and reflected by a high level of inflammation in the peripheral maternal blood, may contribute to fetal demise. Larger studies are needed to confirm our results.

Application of the Fluorescence Method on Sysmex XN9000 Hematology Analyzer for Correcting Platelet Count in Individuals with Microcytosis.

OBJECTIVE: Although small red blood cells are a well-known analytical pitfall that could cause artifactual increase of the platelet count, limited information is available on the accuracy of impedance platelet counting in cases with microcytosis. The aim of this study is to assess the accuracy of impedance platelet counting in the presence of small red blood cells, and to establish the optimal mean corpuscular volume (MCV) cutoff to endorse fluorescence platelet counting. METHODS: In this study, platelet counts estimated by the impedance method on the Sysmex XN9000 analyzer (Sysmex, Kobe, Japan) were compared with those provided by the fluorescence method. The accuracy of impedance platelet counting was assessed. Receiver operating characteristic curve was used to evaluate the performance of MCV in predicting falsely increased platelet counts. RESULTS: There was a tendency for the impedance method to overestimate the platelet count in samples with 70 fL < MCV ≤ 80 fL, 60 fL < MCV ≤ 70 fL, MCV ≤ 60 fL. Receiver operating characteristic curve analysis showed that a 73.5fL cutoff of MCV was highly sensitive in predicting falsely increased platelet counts. CONCLUSION: In cases with MCV < 73.5 fL, we strongly suggest that the platelet counts obtained by the impedance method on the Sysmex XN9000 analyzer should be checked and corrected by fluorescence counting.