Amengual, OForastiero R, RSugiura-Ogasawara, MOtomo, KOku, KFavas, CAlves, JDŽigon, PAmbrožič, ATomšič, MRuiz-Arruza, IRuiz-Irastorza, GBertolaccini, MLNorman, GLShums, ZArai, JMurashima, ATebo, AEGerosa, MMeroni, PLRodriguez-Pintó, ICervera, RSwadzba, JMusial, JAtsumi, T2017-01-102017-01-102016Lupus. 2016 Aug 10. pii: 0961203316660203. [Epub ahead of print]1477-0962http://hdl.handle.net/10400.10/1785OBJECTIVE: A task force of scientists at the International Congress on Antiphospholipid Antibodies recognized that phosphatidylserine-dependent antiprothrombin antibodies (aPS/PT) might contribute to a better identification of antiphospholipid syndrome (APS). Accordingly, initial and replication retrospective, cross-sectional multicentre studies were conducted to ascertain the value of aPS/PT for APS diagnosis. METHODS: In the initial study (eight centres, seven countries), clinical/laboratory data were retrospectively collected. Serum/plasma samples were tested for IgG aPS/PT at Inova Diagnostics (Inova) using two ELISA kits. A replication study (five centres, five countries) was carried out afterwards. RESULTS: In the initial study (n = 247), a moderate agreement between the IgG aPS/PT Inova and MBL ELISA kits was observed (k = 0.598). IgG aPS/PT were more prevalent in APS patients (51%) than in those without (9%), OR 10.8, 95% CI (4.0-29.3), p < 0.0001. Sensitivity, specificity, positive (LR+) and negative (LR-) likelihood ratio of IgG aPS/PT for APS diagnosis were 51%, 91%, 5.9 and 0.5, respectively. In the replication study (n = 214), a moderate/substantial agreement between the IgG aPS/PT results obtained with both ELISA kits was observed (k = 0.630). IgG aPS/PT were more prevalent in APS patients (47%) than in those without (12%), OR 6.4, 95% CI (2.6-16), p < 0.0001. Sensitivity, specificity, LR + and LR- for APS diagnosis were 47%, 88%, 3.9 and 0.6, respectively. CONCLUSIONS: IgG aPS/PT detection is an easily performed laboratory parameter that might contribute to a better and more complete identification of patients with APS.engSystemic lupus erythematosusAntiphospholipid syndromeThrombosisLúpus eritematoso sistémicojournal article10.1177/0961203316660203