Immature platelet fraction measurement: a future guide to platelet transfusion requirement after haematopoietic stem cell transplantation

summary. The decision to prophylactically transfuse platelets is dependent on the platelet count, careful regular clinical assessment and agreed local protocol. The ability to predict when platelet recovery will occur should allow a more reasoned approach to platelet transfusion. An increase in reticulated platelets demonstrates impending platelet recovery. A new rapid automated method to assess reticulated platelets, the immature platelet fraction (IPF), is described, and its clinical utility assessed. The IPF is identified by flow cytometry with the use of a nucleic acid specific dye in the reticulocyte channel on the Sysmex XE-2100. Fifty healthy adult volunteers were used to establish the normal range. Patients where platelet marrow production or destruction might be abnormal were studied, and some patients followed serially during treatment. Thirty patients receiving cytotoxic chemotherapy were tested, and 13 of these patients followed serially. Fifteen patients post-autologous or allogeneic transplant were followed daily for platelet count and IPF percentage to monitor platelet recovery. The method demonstrates good reproducibility and stability. The recovery phase of thrombocytopenia in most chemotherapy and transplant patients was preceded by a rise in IPF percentage several days prior to platelet recovery. In particular, patients undergoing autologous transplantation (n = 8) using peripherally collected stem cells have a characteristic IPF percentage motif, with a rise one or two days prior to engraftment. The automated IPF is a useful parameter in the clinical evaluation of the thrombocytopenic patient and has the potential to allow optimal transfusion of platelet concentrates.     

Sysmex XE-5000血细胞分析仪应用性能评价分析

目的对Sysmex XE－5000全自动血细胞分析仪性能作初步评价。方法按照美国临床实验室标准化委员会（NCCLS）和国际血液学标准化委员会（ICSH）制定的有关文件对其各方面的性能包括空白试验、精密度、线性、携带污染等各指标进行评价。结果XE-5000各项指标的空白试验良好；批内和批间精密度高（CV〈3％）；各指标线性良好（a值在1±0．05范围内，相关系数R^2≥0．975），线性范围宽；各参数的携带污染率低（〈1％）；与现有仪器检测结果可比性强（差异百分率〈3％）；与人工显微镜镜检分类相比，相关性良好（R^2〉0．8）。结论XE-5000各项指标性能良好，基本符合其技术指标，是一款较理想的全自动血细胞分析仪，满足各大、中型医院的需要。     

Sysmex CS5100检测高浓度D-二聚体的稀释验证分析

目的探讨高浓度D-二聚体在抗原过剩情况下是否需要进行稀释处理及最适稀释倍数。方法采用Sysmex CS5100分析仪对D-二聚体质控品与校准品进行检测,计算批内与日间精密度。检测校准品进行线性范围及临床可报告范围验证。对D-二聚体水平小于5mg/L、纤维蛋白降解产物(FDP)20μg/mL的标本进行梯度稀释,检测并计算回收率。对D-二聚体水平大于5mg/L、FDP20μg/mL的标本进行梯度稀释,检测并计算回收率。结果批内及日间精密度分析结果显示,批内及日间变异系数均小于3%。线性范围验证结果显示,0.207~5.170mg/L范围内线性分布良好。临床可报告范围为0.207~165.440mg/L。D-二聚体水平小于5mg/L、FDP20μg/mL时,D-二聚体检测无抗原过剩现象,无需进行梯度稀释检测。D-二聚体水平大于5mg/L、FDP20μg/mL时,D-二聚体检测存在抗原过剩现象,需进行稀释处理。结论当标本D-二聚体水平大于5mg/L、FDP20μg/mL时,D-二聚体检测存在抗原过剩现象,需进行稀释处理,从而保证高浓度D-二聚体标本检测结果的准确性。     

基于Sysmex XS-1000i血液分析仪故障维修论预防性维护的价值

目的比较分析Sysmex XS-1000i型血液分析仪故障维修方法,探讨预防性维护的价值。方法选择2011年1月至2013年12月三年中我院使用该血液分析仪的故障维修案例为研究组,2010年至2013年国内参考文献对同型号血液分析仪的故障维修案例作为对照组,比较分析两组故障发生的频次。结果主要故障发生频次依次为PLT采样错误,废液不排出,测量杯口溢液,白细胞不分类,等。结论该设备的多数故障都是由于设备长期使用,水路管路通道清理不干净引起。制定完善可行的预防性维护内容并严格规范执行,对延长血液分析仪寿命,减少故障发生率,为临床提供准确可靠的数据具有重要作用。     

长沙市健康成人UF-100尿沉渣参数的调查

目的对长沙市健康成人尿沉渣参数进行测试。方法选取长沙市健康成人215人,用UF-100全自动尿沉渣分析仪检测尿液中的尿沉渣参数值。结果长沙市健康成人尿沉渣红细胞、白细胞、上皮细胞、管型正常上限值分别为:22.4/μL、22.2/μL、16.8/μL、1.02/μL。结论确定尿沉渣参数正常参考值对病人的疾病诊断、治疗以及疗效观察有一定的临床价值。     

Immature platelet fraction levels in a variety of bone marrow pathologies in South African HIV-positive patients with thrombocytopenia

Objectives

Thrombocytopenia is common in HIV-infected individuals and often requires a diagnostic bone marrow examination. Interpretation may, however, be limited due to the multifactorial nature of HIV-associated thrombocytopenia and the difficulty in assessing megakaryocyte function morphologically. The immature platelet fraction (IPF) is a parameter which reportedly reflects megakaryocyte activity, with an IPF >7.7% suggesting increased platelet production. The aim of this study was to correlate the IPF with the bone marrow findings as well as other clinical variables of interest in South African patients with HIV-associated thrombocytopenia.

Methods

Seventy-eight HIV-positive patients with thrombocytopenia were enrolled from the Charlotte Maxeke Johannesburg Academic Hospital. The IPF levels were measured using a Sysmex XE-5000 haematology analyzer and were correlated with bone marrow and other findings.

Results

The median IPF was 7.6%, ranging from 1.3 to 44%. It was raised in 78% of patients with immune thrombocytopenia (ITP) (median = 16.3%) and low in 79% of patients with hypocellular marrow (median = 6.5%). Surprisingly, it was highly variable among patients with malignant marrow infiltration and mycobacterial infection of the bone marrow (BMTB) (median = 8.4 and 7.1%, respectively). Mulitivariate linear regression analysis confirmed a significant independent inverse relationship between the IPF and hypocellular marrow (P < 0.0001), a marginally significant positive association with ITP (P = 0.059), and the absence of any relationship with malignant infiltration or BMTB. The IPF had a significant inverse association with the platelet count (P = 0.0006), but was unrelated to the CD4 count and exposure to anti-retroviral therapy. Unexpectedly, it showed a significant positive association with the HIV viral load (P = 0.005). We speculate this to reflect increased megakaryocyte activity in compensation for accelerated platelet clearance due to HIV-driven platelet activation.

Conclusion

This study investigates the role of the IPF in HIV-associated thrombocytopenia, and emphasizes the limitations of morphological analysis in determining megakaryocyte function.