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Updated: Aug 14, 2025
Mapping Metabolism: Monitoring Lactate Dehydrogenase Activity Directly in Tissue
Published on: June 21, 2018
Validating lactate dehydrogenase (LDH) as a component of the PLASMIC predictive tool (PLASMIC-LDH)
Christopher Chin Keong Liam1,2,3, Jim Yu-Hsiang Tiao1,2, Yee Yee Yap3
1Perth Blood Institute, Perth, Australia.
Background:
The PLASMIC score is a convenient tool for predicting ADAMTS13 activity of <10%. Lactate dehydrogenase (LDH) is widely used as a marker of haemolysis in thrombotic thrombocytopenic purpura (TTP) monitoring, and could be used as a replacement marker for lysis. We aimed to validate the PLASMIC score in a multi-centre Asia Pacific region, and to explore whether LDH could be used as a replacement marker for lysis.
Methods:
Records of patients with thrombotic microangiopathy (TMA) were reviewed. Patients' ADAMTS13 activity levels were obtained, along with clinical/laboratory findings relevant to the PLASMIC score. Both PLASMIC scores and PLASMIC-LDH scores, in which LDH replaced traditional lysis markers, were calculated. We generated a receiver operator characteristics (ROC) curve and compared the area under the curve values (AUC) to determine the predictive ability of each score.
Results:
46 patients fulfilled the inclusion criteria, of which 34 had ADAMTS13 activity levels of <10%. When the patients were divided into intermediate-to-high risk (scores 5‒7) and low risk (scores 0‒4), the PLASMIC score showed a sensitivity of 97.1% and specificity of 58.3%, with a positive predictive value (PPV) of 86.8% and negative predictive value (NPV) of 87.5%. The PLASMIC-LDH score had a sensitivity of 97.1% and specificity of 33.3%, with a PPV of 80.5% and NPV of 80.0%.
Conclusion:
Our study validated the utility of the PLASMIC score, and demonstrated PLASMIC-LDH as a reasonable alternative in the absence of traditional lysis markers, to help identify high-risk patients for treatment via plasma exchange.
