PB0457 - Diluted Russell Viper Venom Test for Lupus Anticoagulant Detection in Pregnancy Population

Background: The association between lupus anticoagulants and pregnancy-related adverse outcomes is highly significant. Widely used in risk assessment, dilute Russell's viper venom time (dRVVT) is a common test for lupus anticoagulants during pregnancy. However, pregnancy induces complex changes in the coagulation system, leading to inconsistent trends in coagulation indicators compared to healthy individuals.

Aims: to investigate the impact of the pregnancy process on dRVVT detection and clinical applications.

Methods: From July 2021 to February 2022, data from 2709 pregnant women's dRVVT tests were analyzed, with 71 healthy non-pregnant individuals as control. Screening tests (LA1), confirmation tests (LA2), and the LA1/LA2 ratio were compared in early, mid and late of pregnancy groups with the control group. In addition, early pregnancy group was used as the observational target, the correlation between the mentioned indicators and pregnancy outcomes were analyzed. Chi-squared test was used to compare the intergroup differences, and logistic regression analysis was conducted for assessing the prognostic factors, with P< 0.05 considered statistically significant.

Results: There was no significant difference in LA1in these groups (P>0.05), however, LA2 decreased and LA1/LA2 increased as pregnancy weeks increased (p < 0.05). LA1 and LA1/LA2 in early pregnancy were correlated with pregnancy outcomes and could serve as independent prognostic factors for adverse pregnancy outcomes (P < 0.01). Additionally, LA1/LA2 was found being the optimal outcome prediction indicator.

Conclusion(s): As pregnancy progresses, LA2 decreases significantly, while LA1 remains unchanged. Existing dRVVT standards for adults may falsely elevate lupus anticoagulant detection during pregnancy. Establishing pregnancy-specific criteria for dRVVT is essential.