Objective To manually re-check routine blood test in patients with platelet count (PLT) below normal reference range.Methods Totally 3 045 outpatients whose PLT were below normal reference range in routine blood test from December 2015 to June 2016 were enrolled at Shandong Provincial Hospital Affiliated to Shandong University.Sysmex XN-9000 hematology analyzer PLT-Ⅰ channel (bioelectrical impedance analysis),PLT-F channel(fluorescent nucleic acid staining),Wright's staining microscope examination and phase-contrast microscope manual counting method were used to retest the level of PLT in patients.Results Patients with PLT below normal reference range were divided into 3 groups:PLT (61-124) × 109/L group,PLT (21-60) × 109/L group and PLT ≤ 20 × 109/L group.Thirty-nine of 2 212 cases in PLT (61-124) × 109/L group presented platelet aggregation under microscope with a coincidence rate of 98.2％ (2 173/2 212);18 of 644 cases in PLT (21-60) × 109/L group presented platelet aggregation under microscope with a coincidence rate of 97.2％ (626/644);9 of 189 cases in PLT≤ 20 × 109/L group presented platelet aggregation under microscope with a coincidence rate of 95.2％ (180/189).There was no statistically significant difference of the coincidence rate among 3 groups(P ＞0.05).In 66 patients with platelet aggregation,re-examination results of PLT via PLT-F channel and manual counting were significantly higher than that of PLT-Ⅰ channel [(114.6 ± 46.7) × 109/L,(148.1 ± 31.2) × 109/L vs (80.8 ± 31.5) × 109/L],the re-examination result of PLT via manual counting was significantly higher than that of PLT-F channel (P ＜ 0.05).There were 66 cases of pseudothrombocytopenia in 3 045 patients,accounting for 2.17％;top 3 reasons of pseudothrombocytopenia were unsuccessful puncture[28.8％ (19/66)],EDTA-K 2 dependence [24.2％ (16/66)] and transfusion of blood products [22.7％ (15/66)].Conclusions Manual smear staining microscope examination is necessary for patients with thrombocytopenia to ehminate pseudothrombocytopenia and to assure the accuracy of testing results.PLT-F channel has a great value in determination of low PLT and it can correct tufted aggregation of platelet under microscope;hematology analyzer PLT-F channel reexamination is preferentially suggested for patients with thrombocytopenia;prediluted manual counting is suggested for patients with incorrect results of PLT-F channel.%目的 对血常规标本中血小板计数(PLT)低于正常参考范围下限患者进行手工复检并分析其意义.方法 选取2015年12月至2016年6月于山东大学附属省立医院门诊就诊且做血常规检测的PLT低于正常参考范围下限的患者3 045例.分别采用Sysmex XN-9000血细胞分析仪PLT-Ⅰ通道(电阻抗法)、PLT-F通道(荧光色素染色法)、瑞士染色镜检法以及手工相差显微镜计数法复检PLT并对检测结果进行分析比较.结果 将3 045例血常规标本中PLT低于正常参考范围下限的患者分为PLT(61 ～ 124)×109/L组、PLT(21 ～60)×109/L组和PLT≤20×109/L组.其中PLT(61～ 124)×109/L组2 212例,镜检可见血小板聚集现象39例,符合率为98.2％(2 173/2212);PLT(21～60)×109/L组644例,镜检可见血小板聚集现象18例,符合率为97.2％(626/644);PLT≤20×109/L组189例,镜检可见血小板聚集现象9例,符合率为95.2％(180/189).3组患者间符合率比较,差异均无统计学意义(均P＞0.05).66例血小板聚集患者经PLT-F通道及手工计数复检的PLT结果明显高于PLT-Ⅰ通道复检结果[(114.6±46.7)×109/L、(148.1±31.2)×109/L比(80.8±31.5)×109/L],且手工计数复检结果明显高于PLT-F通道复检结果,差异均有统计学意义(均P ＜0.05).在3 045例患者中,PLT假性降低共66例,占2.17％,原因前3位依次为穿刺不顺[28.8％ (19/66)]、EDTA-K2依赖[24.2％(16/66)]和输入血液制品[22.7％ (15/66)].结论 对于机检血小板减少的患者标本应进行手工推片染色镜检,排除PLT假性降低以保证检测结果的准确性.由于PLT-F通道在低值血小板测定中应用价值较大,可以纠正镜下血小板小簇聚集的情况,建议对PLT减低的标本先使用PLT-F通道复查,若无法纠正再采用预稀释法手工计数,这样既可保证结果的准确性,也减少了患者取报告的等候时间.
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