In order to eliminate artifactual results, the primary criterion for inclusion in this analysis was prolongation of the PTT, which could not be attributed to heparin or factor deficiency. (30/136); and C, 299% (38/127) (data not shown). PTT testing with the addition Entecavir hydrate of polybrene showed patients with unfractionated heparin anticoagulation: A, 101% (10/99); B, 319% (36/113); and C, 117% (23/196), (data not shown). LA, lupus anticoagulant; dRVVT, dilute Russell Viper Venom Test; PNT, phospholipid-neutralization test; PTT, partial thromboplastin time; PT, prothrombin time. We next evaluated immunological APS results in discrepant versus consistent-positive LA cases (Fig 2). In order to eliminate artifactual results, the primary criterion for inclusion in this analysis was prolongation Entecavir hydrate of the PTT, which could not be attributed to heparin or factor deficiency. This analysis included 295 test samples (from 248 patients) from Groups A, B and C. When multiple LA evaluations were performed on a single TNFRSF4 patient, the patient was characterized as having 1 LA discrepancy if at least one of the LA work-ups demonstrated a simultaneous dRVVT/PNT discrepant result (Fig 2B, ?,DD). Open in a separate window Fig 2. Comparison between consistently positive and discrepant LA results utilizing immunological APS test results in patients (n = 248) with PTT prolongation (not due to heparin or factor deficiency, as noted in the text). Plots A and C represent patients with consistently positive LA results: (A) 333% (39/117) APS-positive, 504% (59/117) APS-negative, and 162% (19/117) with no ELISA testing. (C) Entecavir hydrate PT was performed in 487% (19/39) APS-positive, 424% (25/59) APS-negative and 474% (9/19) with no ELISA testing. Of those tested, 267% (5/19), 48% (12/25) and 444% (4/9) of the PTs were prolonged, respectively. Plots B and D represent patients with discrepant LA results: (B) 69% (9/131) APS-positive, 748% (98/131) APS-negative and 183% (24/131) with no ELISA testing. (D) PT was performed in 667% (6/9) APS-positive, 531% (52/98) APS-negative and 50% (12/24) with no ELISA testing. Of those tested, 100% (6/6), 712% (37/52) and 50% (6/12) of the PTs were prolonged, respectively. Note: Immunological APS studies [anticardiolipin (aCL) and ?2-glycoprotein-I (2GPI), both IgG and IgM antibodies] were Entecavir hydrate measured by ELISA (QUANTA LiteTM; Inova Diagnostics Inc., San Diego, CA, USA). Positivity for APS (manufacturers recommendations) was modified from the Sapporo criteria (Miyakis em et al /em , 2006) and defined as an aCL antibody of IgG and/or IgM isotype with titres 40 IgG antiphospholipid units (GPL) or IgM antiphospholipid units (MPL). The 2GPI antibody titres of IgG and/or IgM isotypes were defined by titres 20 GPL or Entecavir hydrate MPL. APS, antiphospholipid syndrome; ELISA, enzyme-linked immunosorbent assay; LA, lupus anticoagulant; PTT, partial thromboplastin time; PT, prothrombin time. There was a five-fold higher rate of positive APS results in patients with consistently positive LA findings as compared to patients with discrepant LA results (Fig 2A, ?,B,B, first columns). The majority of discrepant cases were APS-negative by immunological testing (11:1 negative/positive ratio). A separate analysis of PT values was also done (Fig 2C, ?,D).D). All LA-discrepant patients, APS-positive patients (Fig 2D, first paired columns) showed PT prolongation (mean PT = 251 s), compared with only one-quarter of LA-consistent, APS-positive patients (Fig 2C, mean PT = 206 s). Our analysis of LA testing indicated that a substantial percentage of the cases were associated with discrepant results, most likely representing false positives. The single largest contributing factor to LA discrepancies appeared to be testing done on patients undergoing active anticoagulation. Almost 80%.