Optimization and evaluation of cut-off values of the prolonged APTT plasma mixing test in distinguishing different reasons
10.3760/cma.j.cn114452-20250506-00282
- VernacularTitle:活化部分凝血活酶时间延长混合血浆纠正试验鉴别不同病因的临界值优化及评价
- Author:
Hong ZHAI
1
;
Wei XU
;
Yuying LI
;
Jingnan SUN
;
Beiying AN
;
Linlin QU
Author Information
1. 吉林大学第一医院检验科，长春 130021
- Publication Type:Journal Article
- Keywords:
Activated partial thromboplastin time;
Mixing study;
Coagulation factor deficiency;
Inhibitors;
Lupus anticoagulant
- From:
Chinese Journal of Laboratory Medicine
2025;48(8):1022-1027
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To validate and optimize the interpretation methods and cut-off values of prolonged activated partial thromboplastin time (APTT) mixing test, in order to elevate the clinical applicational value in differentiating single factor deficiency, positive lupus anticoagulant (LA) and FⅧ inhibitors.Methods:This cross-sectional retrospective study involved 130 cases with single APTT prolongation for unknown reasons who underwent mixing tests in the First Hospital of Jilin University from January 1st, 2022 to December 31st, 2023, including 84 males and 46 females. Rosner index (RI), Percentage correction ("Chang") method, Normal reference interval (NRI) method, differential analysis, post-incubation prolongation time and percentage (including mixed immediately and ) were respectively calculated and analyzed for both immediate mixing and 2-hour post-mixing incubation. According to clinical diagnosis, patients were divided into single factor deficiency (51 cases), positive lupus anticoagulant (LA) (56 cases), and positive factor Ⅷ (FⅧ) inhibitor (23 cases). Receiver operation characteristic (ROC) curve analysis was used to determine the cut-off values for APTT mixing test methods in patients with different reasons for prolonged APTT, which were evaluted and adjusted by AUC, sensitivity, and specificity, and compared with the methods currently used for interpretations.Results:For the single factor deficiency cases, the AUCs of immediate RI index <7.5% and incubated RI index <13.9% were 0.87 and 0.90, respectively, with sensitivities at 87.8% and 83.8%, and specificities at 72.0% and 80.0%, whose combination had sensitivity and specificity at 87.3%, and 94.0%, respectively; the judging accuracy increased from 84.6% (110/130) in currently used rule to 93.1% (121/130). For the positive lupus anticoagulant (LA) cases, the combination of immediate RI index >10.3% and prolonged post-incubation clotting time percentage <9.1% showed 88.5% sensitivity and 99.8% specificity; the judging accuracy improved from 80.0% (104/130) in currently used rule to 86.2% (112/130). For positive FⅧ inhibitor cases, the combination of incubated RI index >17.0% and prolonged post-incubation clotting time percentage >9.1% had 99.8% sensitivity and 100.0% specificity; the judging accuracy increased from 89.2% (116/130) in currently used rule to 94.6% (123/130).Conclusion:This study validated and optimized the interpretation methods and cut-off values for the prolonged APTT mixing test in differentiating single factor deficiencies, prositive FⅧ inhibitors and LA positive cases, significantly improving the judging sensitivity and specificity.
