血小板计数和血小板平均体积在新生儿败血症的意义

目的：了解新生儿败血症血小板计数（BPC）和平均体积（MPV）的变化,分析其临床意义。方法：收集52例符合新生儿败血症确诊标准的患儿临床资料,比较败血症发生前后BPC及MPV相关变化;根据病原菌分为革兰阴性菌（G-）组和革兰阳性菌（G＋）组,根据转归分为存活组和死亡组,进行上述相关参数分析。结果：败血症患儿血小板减少发生率53．8％;发病后与发病前相比,BPC显著降低,MPV增加（P％0．05）。G～组与G＋组相比,血小板减少发生率显著升高（63．89％：31．25％）;BPC平均水平明显降低[（109．83±71.02）×10^9／L：（164．5±85．23）×10^9/L],且最低点水平显著降低[（75．31±42．87）×10^9：（112．06±58．18）×10^9]。死亡组BPC和MPV较存活组降低[（59．91±28．83）×10^9：（144．49±78．80）×10^9]、[（9．61±0．98）：（11．22±1．27）fl]。结论：血小板减少和MPV增加与新生儿败血症相关,能较好地反映病情及预后。     

Platelet count and the risk for thrombosis and death in the elderly

Summary.  Aim: Our aim was to examine the association between platelet count and the incidence of myocardial infarction, ischemic stroke, hemorrhagic stroke, venous thrombosis, and mortality. Methods and results: Platelet count was measured at baseline in 1989–1990 and at 3 years follow-up, or at baseline (for a newly recruited group) in 1992–1993 in 5766 community-dwelling individuals aged 65 years and older (mean age at baseline, 73 years). During 12–15 years of follow-up, there were 821 incident myocardial infarctions, 807 ischemic strokes, 161 hemorrhagic strokes, 159 venous thrombotic events, and 3413 participants died. Platelet count was not associated with the occurrence of myocardial infarction, ischemic or hemorrhagic stroke, venous thrombosis, or cardiovascular mortality. Non-cardiovascular mortality was higher among both participants with low and with high platelet count. Adjusted non-cardiovascular mortality rates for platelet counts below 100, 100–199, 300–399, and above 400 × 10⁹ L⁻¹ relative to the reference mortality rate in participants with platelet count values between 200 and 299 × 10⁹ L⁻¹ were 1.89 (1.21–2.96), 1.08 (0.98–1.20), 1.20 (1.06–1.37), and 1.47 (1.14–1.90), respectively. Conclusion: Platelet counts were not associated with vascular outcomes but low and high platelet counts were associated with non-cardiovascular mortality, including cancer mortality.     

Platelet count and erythrocyte sedimentation rate are good predictors of Kawasaki disease: ROC analysis

Background and Aims: Kawasaki disease (KD) is the leading cause of acquired pediatric cardiac disease and requires a timely diagnosis. Available effective therapy is ideally administered within 10 days of illness diagnosis. Recent reports of several laboratory tests in KD have been published. In this study, we aimed to evaluate the sensitivity and specificity of several laboratory tests. Methods: We performed a retrospective study of consecutive patients diagnosed with KD from January to December 2008. We studied the sensitivity and specificity of several different tests [T‐cell subgroups, platelet count, erythrocyte sedimentation rate (ESR), and C‐reactive protein (CRP)] to predict KD using receiveroperator characteristic curve analysis. Results: No significant difference was demonstrated in T‐cell subgroups between patients with KD and referent patients (P>0.05). However, platelet count, ESR, and CRP were significantly higher in patients with KD than in referent patients (P<0.05). ESR showed a sensitivity of 93.9% and specificity of 83.3% with a cut‐off of 15 mm/hr (area under the curve [AUC], 89.1%; P=0.03). Platelet count showed a sensitivity of 70.6% and specificity of 75% with a cut‐off of 336.5×10⁹/l (AUC, 71.2%; P=0.03). Conclusions: These results indicate that platelet count and ESR are good predictors of KD. J. Clin. Lab. Anal. 24:385–388, 2010. © 2010 Wiley‐Liss, Inc.     

血小板计数与脾面积比值和血小板计数与脾长径比值诊断乙肝肝硬化患者食管静脉曲张的对比研究

目的 比较血小板计数与脾面积比值(PC/SA)和血小板计数与脾长径比值(PC/SD)诊断乙肝肝硬化患者食管静脉曲张(EV)的价值.方法 选取在我院就诊的172例乙肝肝硬化患者,根据胃镜检查结果分为EV组121例和无EV组51例,均行胃镜、血常规及腹部超声检查,采集血小板计数(PC)、脾长径、脾厚径,计算PC/SA和PC...     

Platelet count, platelet function, coagulation activity and fibrinolysis in the acute phase of inflammatory bowel disease

Twenty two patients with exacerbation of inflammatory bowel disease (19 with Crohn's disease, 3 with ulcerative colitis) and thrombocytosis were tested for possible activation of the coagulation and platelet system. Fifteen patients had abnormal platelet function i.e. unphysiologically high sensitivity in vitro towards ADP 2 mumol/l aggregation induction. In 81.8% of the patients we found enhanced fibrinogen concentrations. In 22.7% of the patients thrombin-antithrombin III values exceeded the upper limit of the reference range, and in 68.2% of the patients the D-Dimer concentration exceeded the upper reference limit as a result of reactive fibrinolysis. The altered platelet count and function, and the increased levels of fibrinogen and thrombin-antithrombin III with reactive fibrinolysis activation indicate the presence of prethrombotic factors in patients with exacerbation of inflammatory bowel disease. The presence of enhanced fibrinolysis in these patients might have consequences for the therapeutic treatment.     

White blood cell count and differential count

Current methods for performing the white blood cell count and differential count along with recent technologic advances are discussed. Sources of error and variation in these tests are presented. The use of the white blood cell count and the differential count in a variety clinical situations is reviewed.     

Platelet count is a sensitive predictor of autologous peripheral blood progenitor cell collection yield in previously treated plasma cell disease patients

BACKGROUND: It is often a clinical dilemma to determine when to collect autologous peripheral blood progenitor cells (PBPCs) in patients who received prior chemotherapy. It is also challenging to predict if the collected cells will be enough for one or two transplants. STUDY DESIGN AND METHODS: A total of 103 PBPC donors were followed to evaluate factors that predict poor autologous PBPC collection. The donors were categorized into three groups: plasma cell disorders (PCDs), lymphomas, and normal allogeneic donors. RESULTS: Our evaluation showed that platelet (PLT) count before growth factor administration significantly correlated with total CD34+ cell yield (Spearman r = 0.38, p < 0.001). Further analysis showed this correlation was only significant in plasma cell disease patients who received prior chemotherapy (Spearman r = 0.5, p = 0.008). Baseline PLT counts did not correlate with PBPC collection yield in untreated PCD, lymphoma, and normal allogeneic donors. In addition, daily PLT count during PBPC harvest correlated with CD34+ cell yield for that day (Spearman r = 0.41, p < 0.001). With a multiple linear regression model (adjusted R(2) = 0.31, AIC = 63.1), it has been determined that the baseline PLT count significantly correlates with total CD34+ cell yield in treated PCD patients. CONCLUSION: Baseline PLT count is a sensitive indicator of autologous PBPC mobilization in PCD patients who received prior chemotherapy. This finding may be considered before growth factor administration to determine the optimal period to mobilize treated PCD patients and to predict if enough cells can be collected for one or two transplants.     

Platelet disorders

The pathogenesis of suboptimal platelet function is multifactorial. Platelets do not function well if there are too many or too few platelets; also the platelets can be present in the appropriate quantity but be dysfunctional due to abnormal shape or size. This article will give a brief overview of normal platelet physiology and megakaryocytopoiesis and then discuss platelet dysfunction in the neonatal population. Knowledge regarding the varied causes of platelet dysfunction will lead to expedient identification and appropriate treatment for affected infants.     

Platelet thromboembolism

Abstract. Platelet-dependent thrombosis and subsequent embolization are major causes of cerebral ischaemia. Beside aspirin which irreversibly blocks platelet cyclo-oxygenase, several other substances interfere in different platelet metabolic pathways and block platelet adhesion and aggregation. We found in an experimental model using non-human primates that a specific peptide inhibitor blocking GP IIb/IIIa platelet receptor which binds fibrinogen completely, prevents the retention of embolized platelet aggregates in the cerebral circulation. As thrombin may play a key role for platelet activation in vivo leech-derived hirudin, a direct thrombin inhibitor as well as activated protein C which limits thrombin production and also prevents platelet dependent thrombus formation very effective. We demonstrated in the same non-human primate model of platelet embolization that the amount of retention of platelet emboli in the vascular bed depends on the nature of the vasculature. For example, platelet emboli were cleared very quickly from brain microcirculation, whereas platelet embolization into the lower limb via the femoral artery caused a significantly longer retention of the embolized material. Such specific mechanisms may be caused by different levels of local vasodilators as PGI₂ or EDRF.     

Platelet Disorders

Practical considerations concerning long-term oral anticoagulant therapy are often the responsibility of the primary care physician. Decisions need to be made regarding dose adjustment, frequency of follow-up, and interruption of therapy for dental and noncardiac surgical procedures. Drs Sebastian and Varkey address these and other aspects of anticoagulant therapy and also review indications, contraindications, and complications.