Platelet counting

Platelet counting is a daily basic hematological analysis of crucial interest in many clinical situations. Historical manual techniques (phase-contrast microscopy) have been replaced by automated techniques (impedance or optical analyzers) more rapid and precise. More recently, flow cytometry techniques using labeled monoclonal antibodies have been proposed as reference techniques. Nevertheless, pre-analytical and analytical variables should be respected to obtain reliable results and avoid validation pitfalls

Platelet morphology analysis

Platelets are very small blood cells (1.5-3 μm), which play a major role in primary haemostasis and in coagulation mechanisms. Platelet characterization requires their counting (see Chapter 15 ) associated with accurate morphology analysis. We describe the major steps in order to correctly obtain stained blood films, which can be analyzed by optical microscope. Platelet morphology abnormalities are found in acquired malignant hematological diseases such myeloproliferative or myelodysplastic syndromes and acute megakaryoblastic leukemia. A careful analysis of the platelet size and morphology, by detecting either normal platelets with or without excessive anisocytosis, microplatelets, or large/giant platelets, will contribute to inherited thrombocytopenia diagnosis and gather substantial data when looking for an acquired platelet disorders

Diagnostic and prognostic value of plasma volume status at emergency department admission in dyspneic patients: results from the PARADISE cohort

International audienceBackground:Systemic congestion, evaluated by estimated plasma volume status (ePVS), is associated with in-hospital mortality in acute heart failure (AHF). However, the diagnostic and prognostic value of ePVS in patients with acute dyspnea has been insufficiently studied.-- Objectives:To assess the association between the first ePVS calculated from blood samples on admission in the emergency department (ED) and discharge diagnosis of AHF and in-hospital mortality in patients admitted for acute dyspnea.-- Methods:The study included 1369 patients admitted for dyspnea in the ED in 2015. ePVS was calculated from hematocrit and hemoglobin values at admission. Comparisons of baseline characteristics according to ePVS tertiles were carried out and then associations between ePVS and the two outcomes “AHF diagnosis” and “intra-hospital mortality” were assessed using a logistic regression model.-- Results:36.6% had a BNP > 400 pg/mL and median ePVS was 4.58 dL/g [3.96–5.55]. Overall in-hospital mortality was 11.1% (n = 149). In multivariable analysis, the third ePVS tertile (> 5.12 dL/g) had a significantly increased risk of having AHF (OR = 1.64 [1.16–2.33], p = 0.005). In-hospital mortality rose across ePVS tertiles (8.4–13.8% p < 0.01). ePVS greater than the first or second tertile threshold (respectively, 4.17 dL/g and 5.12 dL/g) were both significantly associated with a higher risk of in-hospital mortality (OR for 2nd/3rd tertile = 2.06 [1.25–3.38], p = 0.004 and OR for 3rd tertile = 1.54 [1.01–2.36], p = 0.04).-- Conclusion:Higher ePVS values determined from first blood sample at admission are associated with a higher probability of AHF and in-hospital mortality in patients admitted in the ED for acute dyspnea