Real-World Retrospective Audit on the Use of the TechnoClone TECHNOSCREEN ADAMTS-13 Assay in the Diagnostic Process for Thrombotic Thrombocytopenic Purpura at LabPlus, New Zealand

Introduction: The TECHNOSCREEN ADAMTS-13 assay (ADSC) is a new lateral flow test which is simple and quick to perform, with a high negative predictive value (NPV); it may improve the diagnostic workflow for TTP. LabPlus in Auckland, New Zealand, performs all ADAMTS13 tests in the Auckland and Northland regions. The ADSC was used at LabPlus between 2022 and 2023 as part of a protocol where results of 0 IU/mL and 0.1 IU/mL were confirmed with the TECHNOZYM ADAMTS-13 Activity chromogenic ELISA assay (ADATS). The aim was to improve cost efficiency by reducing the need for the labour-intensive ADATS, particularly in low probability requests. This retrospective audit analyses the efficacy and efficiency of the testing protocol.

Methods: All ADAMTS-13 tests performed in the year before the ADSC (March 2021-March 2022) and after the ADSC protocol was introduced (March 2022-March 2023) were collected from the LabPlus laboratory information system (LIS), and correlated with clinical information from the electronic health record. Statistical analysis was performed.

Results: Ninety-four test requests were audited. ADSC had an NPV of 100% on diagnostic samples. The protocol increased the median turn-around time (TAT) by 18 h (p = 0.01). If an ADSC of 0.1 IU/mL was taken as a negative, the median TAT was decreased by 17 h (p = 0.0003) in diagnostic samples from LabPlus adjacent hospitals.

Conclusion: ADSC has a high NPV but did not improve TAT when used as part of a testing protocol for our central laboratory receiving samples from a large area.