McClure S, Bates J E, Harrison R, Gilmer P R, Bessman J D
Department of Internal Medicine, University of Texas Medical Branch, Galveston 77550.
Am J Clin Pathol. 1988 Aug;90(2):163-8. doi: 10.1093/ajcp/90.2.163.
Increasingly, all automated blood counts are not accompanied by a microscopic white blood cell differential. A popular strategy is to obtain a manual differential if any part of the automated blood count and differential is outside specified limits (the "diff-if" strategy). The authors compared two sets of criteria to triage blood counts for manual differentials: previously recommended numeric values, and the analysis of a microcomputer program. In a population of subjects with a high percentage of hematologic disorders, the microcomputer program and the numeric criteria were equally specific (excluding normal blood smears); the program was more sensitive for bands, immature granulocytes, monocytes, nucleated red blood cells, reticulocytosis, teardrops, red blood cell fragments, and hypersegmented neutrophils. The numeric criteria were more sensitive for eosinophilia (less than 1.0 X 10(9)/L) and mandated fewer manual differentials. In a population of predominantly normal subjects, the program was more sensitive for increased bands and equally sensitive for eosinophilia, the only abnormalities observed on the smear. In a population of subjects with predominantly abnormal blood counts, but excluding most primary hematologic disorders, there were few blood smears with abnormalities beyond eosinophilia or increased bands. In both of these groups, the computer program mandated more manual differentials than did the numeric criteria. The authors conclude that microcomputer analysis by the program tested was more sensitive than numeric criteria to identify specimens with abnormal blood smears. Specificity depended on the patient population. The choice of a triage strategy should be based on the individual laboratory's patient population.
越来越多的全血细胞自动计数不再伴有白细胞显微镜分类计数。一种常用的策略是，如果自动血细胞计数及分类的任何部分超出规定范围，就进行手工分类计数（“异常即分类”策略）。作者比较了两组用于筛选需进行手工分类计数的血细胞计数标准：先前推荐的数值标准，以及一个微机程序的分析结果。在血液病比例较高的人群中，微机程序和数值标准的特异性相同（排除正常血涂片）；该程序对杆状核细胞、未成熟粒细胞、单核细胞、有核红细胞、网织红细胞增多、泪滴形细胞、红细胞碎片及多分叶核中性粒细胞更为敏感。数值标准对嗜酸性粒细胞增多（低于1.0×10⁹/L）更为敏感，且需要进行手工分类计数的情况较少。在以正常受试者为主的人群中，该程序对杆状核细胞增多更为敏感，对嗜酸性粒细胞增多的敏感性相同，这是血涂片上仅观察到的异常情况。在以血细胞计数主要异常但排除大多数原发性血液病的人群中，除嗜酸性粒细胞增多或杆状核细胞增多外，很少有血涂片存在其他异常。在这两组人群中，计算机程序要求进行手工分类计数的情况比数值标准更多。作者得出结论，所测试的程序进行微机分析比数值标准在识别血涂片异常标本方面更为敏感。特异性取决于患者群体。筛选策略的选择应基于各个实验室的患者群体。
