Clin Chem Lab Med. 2014 Dec;52(12):1763-70. doi: 10.1515/cclm-2014-0320.
Peripheral smear review is a critical, but labor intensive adjunct for evaluation of lymphocytosis. Standard practice based on consensus guidelines is to review cases with absolute lymphocyte count (ALC) >5×109/L. We hypothesize that identifying cases for review by applying appropriately adjusted ALC and age discriminators will decrease laboratory workload without compromising patient care.
1170 complete blood counts with ALCs >5×109/L analyzed in the core laboratory during a 2-year period were included. Patients were categorized into diagnostic groups based on follow-up criteria. A total of 402 patients with new onset lymphocytosis who met criteria for reactive lymphocytosis (82%) or lymphoproliferative disorder (18%) were used to establish optimal ALC and age thresholds from receiver operating characteristic (ROC) curve analysis.
ALC as a discriminator for neoplastic lymphocytosis had an ROC area under the curve (AUC) of 0.732. Selecting cases with ALC >10×109/L enriched the proportion of neoplastic cases in the review pool (90% specificity); however, many cases with ALC below this threshold were also neoplastic (52% sensitivity). For cases with ALC between 5 and 10×109/L, age as a discriminator had an ROC AUC of 0.886. Selecting patients >50 years old in this group for review captured the neoplastic cases while excluding the reactive cases (93% sensitivity, 62% specificity). When applied to a validation cohort, the predictive performance of the thresholds was maintained while reducing smears reviewed by 50%.
We show that modifying the standard 5×109/L ALC smear review threshold through retrospective analysis of institutional data can reduce laboratory workload without compromising quality.
外周血涂片检查是评估淋巴细胞增多症的重要但劳动强度大的辅助手段。基于共识指南的标准做法是，对绝对淋巴细胞计数（ALC）>5×109/L 的病例进行复查。我们假设，通过应用适当调整的 ALC 和年龄鉴别器来识别需要复查的病例，可以在不影响患者护理的情况下减少实验室工作量。
在 2 年期间，对核心实验室中分析的 1170 例 ALC>5×109/L 的全血细胞计数进行了研究。根据随访标准，将患者分为诊断组。共有 402 例新发生的淋巴细胞增多症患者符合反应性淋巴细胞增多症（82%）或淋巴增生性疾病（18%）的标准，用于通过接受者操作特征（ROC）曲线分析建立最佳 ALC 和年龄阈值。
ALC 作为肿瘤性淋巴细胞增多症的鉴别诊断指标，ROC 曲线下面积（AUC）为 0.732。选择 ALC>10×109/L 的病例可使复查池中肿瘤病例的比例增加（特异性为 90%）；然而，许多 ALC 低于此阈值的病例也是肿瘤性的（敏感性为 52%）。对于 ALC 在 5 到 10×109/L 之间的病例，年龄作为鉴别诊断指标的 ROC AUC 为 0.886。在此组中选择年龄>50 岁的患者进行复查可捕获肿瘤病例，同时排除反应性病例（敏感性为 93%，特异性为 62%）。当应用于验证队列时，这些阈值的预测性能得以保持，同时减少了 50%的涂片复查。
我们通过对机构数据的回顾性分析表明，通过修改标准的 5×109/L ALC 涂片复查阈值，可以在不影响质量的情况下减少实验室工作量。
