Department of Internal Medicine, John H. Stroger Jr. Hospital of Cook County, Chicago, Illinois, USA.
Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Transfusion. 2020 Sep;60(9):2047-2057. doi: 10.1111/trf.15954. Epub 2020 Aug 5.
The PLASMIC score was developed to identify patients with thrombotic microangiopathy who are most likely to have immune thrombotic thrombocytopenic purpura (TTP) and benefit from therapeutic plasma exchange (TPE). PLASMIC scores of 0-4, 5, and 6-7 are said to correspond to low, intermediate, and high probability of TTP, respectively.
We conducted a systematic review and meta-analysis on the diagnostic accuracy of the PLASMIC score in adults with suspected TTP. We evaluated the sensitivity, specificity, positive predictive value, and negative predictive value (NPV) of PLASMIC score thresholds of ≥5 and ≥6. Study quality was appraised using the QUADAS-2 tool.
We identified 13 eligible studies, which collectively enrolled 970 patients. The median prevalence of TTP among eligible studies was 35%. The sensitivity and specificity of a PLASMIC score ≥5 was 0.99 (95% confidence interval [CI], 0.91-1.00) and 0.57 (95% CI, 0.41-0.72), respectively. At a prevalence of 35%, the NPV of a PLASMIC score ≥5 was 0.99 (95% CI, 0.92-1.00). A PLASMIC score ≥6 was associated with a sensitivity and specificity of 0.85 (95% CI, 0.67-0.94) and 0.89 (95% CI, 0.81-0.94), respectively. The NPV of a PLASMIC score ≥6 at a prevalence of 35% was 0.92 (95% CI, 0.82-0.97).
A PLASMIC score threshold of ≥5 is associated with high sensitivity and NPV and may be a useful screening tool for identifying patients who are unlikely to have TTP and do not require TPE, though prospective assessment is required. A PLASMIC score <6 appears to have insufficient sensitivity to rule out TTP and the need for TPE.
PLASMIC 评分旨在识别最有可能患有免疫性血栓性血小板减少性紫癜（TTP）并受益于治疗性血浆置换（TPE）的血栓性微血管病患者。PLASMIC 评分 0-4、5 和 6-7 分别对应于 TTP 的低、中、高概率。
我们对成人疑似 TTP 中 PLASMIC 评分的诊断准确性进行了系统评价和荟萃分析。我们评估了 PLASMIC 评分阈值≥5 和≥6 的敏感性、特异性、阳性预测值和阴性预测值（NPV）。使用 QUADAS-2 工具评估研究质量。
我们确定了 13 项符合条件的研究，这些研究共纳入了 970 名患者。合格研究中 TTP 的中位患病率为 35%。PLASMIC 评分≥5 的敏感性和特异性分别为 0.99（95%置信区间[CI]，0.91-1.00）和 0.57（95%CI，0.41-0.72）。在患病率为 35%的情况下，PLASMIC 评分≥5 的 NPV 为 0.99（95%CI，0.92-1.00）。PLASMIC 评分≥6 与 0.85（95%CI，0.67-0.94）和 0.89（95%CI，0.81-0.94）的敏感性和特异性相关。在患病率为 35%的情况下，PLASMIC 评分≥6 的 NPV 为 0.92（95%CI，0.82-0.97）。
PLASMIC 评分阈值≥5 与高敏感性和 NPV 相关，可能是一种有用的筛选工具，用于识别不太可能患有 TTP 且不需要 TPE 的患者，尽管需要前瞻性评估。PLASMIC 评分<6 似乎不足以排除 TTP 和 TPE 的必要性。
