血小板分布异常原因分析及对血小板计数的影响

The reasons of abnormal platelet distribution and the effects on the platelet count

目的对血常规标本报告血小板分布异常的影响因素进行研究,并探讨这些因素对电阻抗法和核酸荧光染色法血小板计数结果差异的影响。方法采用Sysmex-XE5000全自动血液分析仪电阻抗法和核酸荧光染色法对340例血常规标本参数进行研究分析,通过非配对t检验比较血小板分布异常和血小板分布正常分组红细胞平均容量(MCV)、血小板分布宽度(PDW)、电阻抗法血小板计数(PLT-I)和未成熟血小板比率(IPF%)4项参数之间的差异,发现血小板分布异常标本血常规参数的一般特征;采用配对t检验比较血常规分布异常标本PLT-I和核酸荧光染色法血小板计数(PLT-O)结果的差异并分析差异与以上4项参数之间的关系。结果血小板分布异常与正常组比较MCV、RDW、IPF%和PLT-I差异有统计学意义(P<0.05),以MCV≤65.0fL、RDW≥25.9、PLT-I≤50×109/L或IPF%≥7.0%作为临界值,预测血小板分布情况与仪器报告实际报告情况的符合关系,敏感度为83.1%,特异度为87.2%。血小板分布异常组PLT-I与PLT-O法血小板计数结果有极显著差异,以PLT-I减低、IPF%升高为主,PLT-I一般小于PLT-O,以MCV减低、RDW升高为主,则PLT-I大于PLT-O。结论以上数据说明血小板分布异常与样本本身存在红细胞体积明显减小、红细胞大小显著不均或破碎、血小板减少和未成熟血小板比例升高有关,而这些因素又会干扰PLT-I法计数结果的准确性。血小板计数减低、未成熟血小板比率升高易造成电阻抗法血小板计数假性降低;小红细胞、红细胞大小不一、红细胞碎片易造成电阻抗法血小板计数假性升高。临床上为提高血小板计数的准确性,对血小板分布异常标本应使用核酸荧光染色法报告结果,电阻抗法易受以上因素干扰。

Objective To find the influence factors of Sysmex XE-5000 reporting abnormal platelet distribution,and discuss the relevence between the factors and the platelet count difference from two kinds of methods. Methods Compared the four parame-ters, MCV,RDW,PLT-I and IPF%, between normal and abnormal platelet distribution group by unpaired t-test, and find the the general characteristics of abnormal distribution specimens. Compared the counting difference between impedance （PLT-I） and nu-cleic acid fluorescent staining （PLT-O） methods by paired t-test within the abnormal distribution group. Results MCV, RDW, IPF% and PLT-1 all had significant differences between normal and abnormal platelet distribution groups（P〈0.05）. Set MCV≤ 65.0 fL.RDW≥25.9.PLT-I≤50 × 10^9/L or IPF%≥7.0% as a critical value to predict the abnormal platelet distribution, the sen-sitivity was 83.1 0% and the specificity was 87.2%. The platelet count results had significant differences between PLT I and PLT-O methods within abnormal distribution group. The count of PLTI was less than that of PLT-O when the specimen mainly has low PLT count and high IPF% ,conversely,the count of PLT-I was more than that of PLT-O when the sample mainly had low MCV and high RDW. Conclusion The data above shows that abnormal platelet distribution is related to the sample itself in which MCV decrease,RDW increase,thrombocytopenia or immature platelet increase. These factors may interfere with the accuracy of PLT-I platelet count results. The platelet count decreases,immature platelet ratio increases may reduce platelet count falsely, otherwise small red blood cells,cell fragments may rise platelet count falsely. In conclusion, to improve the accuracy of the platelet count on specimens with abnormal platelet distrihution,PLT-O method should be used to report PLT count results.