Skip to main content
ISTH 2024 Main banner
Back

Poster Networking

Diagnostics, OMICs and Advanced Technologies

PB0137 - Evaluation of Clot Waveform Analysis in Patients with Positive Lupus Anticoagulant

Sunday, June 23, 2024
13:45 – 14:45 ICT
Room: Exhibition Hall
Background: There has been limited literature describing the parameters of activated partial thromboplastin (aPTT) based clot waveform analysis (CWA) in lupus anticoagulant (LA) patients.

Aims: To describe quantitative and qualitative CWA parameters in LA positive samples.

Methods: This was a retrospective study that reviewed all positive LA samples and associated CWA parameters from January to December 2023. The sample is considered positive if at least one test system - the aPTT (silica activator) or Dilute Russell Viper Venom Test (DRVVT) - is positive. A total of 80 samples were included. Paired aPTT-CWA using Dade Actin FSL (ellagic acid as activator) were analysed on Sysmex CS2500 coagulometer.

Results: Quantitative APTT-based CWA parameters are shown in table 1. Unadjusted CWA parameters were not different (p>0.05) between the LA-positive samples and normal controls. Adjusted CWA parameters, however, were lower in LA-positive samples (p < 0.05). No differences were found between non-triple positivity versus triple positivity (i.e positive for anti-cardiolipin IgM/IgG and anti-B2 glycoprotein I IgM/IgG). Review of morphological CWA waveforms (n=55) showed normal morphology with no atypical first or second derivative curves noted. In patients that were single positive LA (n=58), a higher adjusted min1 was significantly associated with increased odds of thrombosis, HR 2.28 (95% CI: 1.10 – 4.71, p=0.026). This significant association was not seen in aPTT and unadjusted min1 (Figure 1).

Conclusion(s): In a consecutive cohort of positive LA samples, no atypical CWA derivatives curves were observed with no difference in unadjusted CWA parameters with normal healthy controls. Adjusted CWA parameters however were lower in LA-positive samples. In singly positive LA patients, a positive significant association between adjusted CWA parameters and thrombotic outcomes was seen. Further studies would help to determine the utility of CWA in LA and APLAs testing and its associated thrombotic outcomes.