PB0973 - Lupus anticoagulant test in Low-middle income Country : ISTH guidance versus local Methods

Background: The term of lupus anticoagulant (LA) had first been used by Fernstein and Rapaport in 1972.
It designed an acquired inhibitor of blood coagulation found in the plasma of patient with Systemic Lupus Erythematosus (SLE).
LA occurs in mamy other autoimmune diseases and is one of biological criteria of Antiphospholips Syndrome (APS) define in Sapporo (1999) then Sydney (2004).
LA detection is base on a fonctionnal coagulation procedure characterized by a poor standardisation ; lead to difficulties in interpreting results.
In 2018 the only guidance from the Scientific an Standardization Committee for lupus anticoagulant/antiphospholipids antibodies of ISTH was done in 2009.

Aims: In 2018, we decided to detect LA in patients with systemic autoimmune diseases according to ISTH recommandation and compare it to our local method in Low Middle Income Country.
We collected sample from patients with SLE, Scleroderma, Dermatomyosis, APS,…. With a majority of females.

Methods: We compared ISTH guidance in 5 steps: (APTT, then correction, DRVVT (screen and confirm), screen for facteur deficiency) and our local method in only three step (DRVVT screen, DRVVT confirm and exclude FVIII defiency (because the most prevalent circulating anticoagulant in these patient after LA is FVIII acquired anticoagulation)).

Results: We collected sample from 55 patients with a mean age of 40 range from 18 to 71 years old.
According to ISTH method, only 7 patients (12,7%) had a LA, compared to our direct screening local method where 34 patients (61,8%) had a circulation anticoagulant. Diseases most associated to LA were SLE, Dermatomyosis, SS. Only one patient had FVIIIc deficiency.

Conclusion(s): So in LMICs, to reduce the step and reagents use in those specific patients with a high risk of developping LA, the study show that we can skip the step of screening with APPT. So we would have more chance to find LA.