PB0410 - DRVVT in APLA- As a single test and in combination with Anti B2-Glycoprotein and Anti Cardiolipin.

Sunday, July 10, 2022

6:30 PM – 7:30 PM

Location: Exhibition

Presentation Format: In-Person

Presenting Author(s)

Priyavadhana Balasubramanian, MD

Assistant Professor
All India Institute of Medical Sciences, AIIMS, Rishikesh
Rishikesh, Uttarakhand, India

Co-Author(s)

Tulasi Geevar, MBBS, MD

Associate Professor
Christian Medical College and Hospital Vellore
Vellore, Tamil Nadu, India
Rutvi Gautam Dave, MBBS, MD, Post-Doctoral Fellow

Associate Professor
Christian Medical College and Hospital Vellore
Vellore, Tamil Nadu, India
JJ

John Antony Jude prakash

Professor
Christian Medical College, Vellore
Vellore, Tamil Nadu, India
JM

John Mathew

Professor
Christian Medical College, Vellore
Vellore, Tamil Nadu, India
AA

Anuja Abraham

Professor
Christian Medical College, Vellore
vellore, Tamil Nadu, India
JL

Jeyaseelan L

Professor
Christian Medical College, Vellore
Vellore, Tamil Nadu, India
SN

Sukesh Chandran Nair

Professor
Christian Medical College and Hospital Vellore
Vellore, Tamil Nadu, India

Background: APLA is one of the most common acquired thrombophilias.

Aims: To study the significance of dilute russel viper venom test (DRVVT) towards the diagnosis of antiphospholipid antibody syndrome (APLA) – As a stand alone test and in combination with antibodies to β2-glycoprotein I (anti-β2- GPI) and cardiolipin (aCL).

Methods: This was a six month retrospective study. The electronic medical records of 451 patients referred for lupus anticoagulant (LAC) test were reviewed. LAC was done by DRVVT. Anti IgG, IgM β2-GPI and IgG aCL were done by enzyme linked immunosorbent assay (ELISA).

Results: 451 patients were referred for LAC test in view of arterial thrombosis (12.4%), venous thrombosis (10.1%), thrombocytopenia (7%), pregnancy morbidity (8.6 %), systemic lupus erythematosus (16%), other autoimmune causes (6.8%). DRVVT positivity was seen in 49 cases (23%).Mild positivity in 29, moderate in 14 and marked in 6 cases. In DRVVT positive patients, IgG anti-β2-GPI was positive in 8 cases, IgM anti-β2-GPI in 9 and IgG aCL in 15 cases. Repeat LAC testing was sent only for 12 cases. Triple positivity was seen in 10 out of 29 cases. In DRVVT negative patients (89%), IgG anti-β2-GPI was negative in all cases, IgM anti-β2-GPI was positive in 21 cases and IgG aCL in 5. In other indications (38.5%) referred for LAC, only two cases were mild positive for DRVVT.

Secondary causes were excluded for analysis of sensitivity, specificity of different test modalities (Table 1). DRVVT had highest sensitivity and specificity in cases presenting with thrombosis. IgG aCL was more specific in arterial thrombosis and anti IgG β2 GPI was more specific in venous thrombosis,thrombocytopenia and abortions.

Conclusion(s): APLA is diagnosed based on clinical and laboratory criteria. DRVVT as a single test has higher sensitivity and specificity in thrombosis but simultaneous testing for other antiphospholipid antibodies increases the specificity.