title: Prolonged Activated Partial Thromboplastin Time: Difficulties in Discriminating Coexistent Factor VIII Inhibitor and Lupus Anticoagulant.
abstract: To review the diagnostic difficulties of a prolonged activated partial thromboplastin time (aPTT) when 2 inhibitors with opposite clinical presentations coexist, we searched MEDLINE from January 1970 to November 2013 using acquired, factor VIII (FVIII), factor IX, hemophilia A and B, inhibitor, lupus anticoagulant (LA), antiphospholipid, anticardiolipin, anti-β2-glycoprotein I, antibodies, syndrome, bleeding, and thrombosis. We identified 13 articles for a total of 15 cases of possible coexistence of FVIII inhibitor and LA. The presenting clinical manifestation was thrombosis in 6 cases and bleeding in 9 cases. Activated partial thromboplastin time was the presenting laboratory abnormality in all cases, and first-line investigations suggested the coexistence of LA and acquired FVIII inhibitor. None of the articles addressed the diagnostic accuracy of the screening tests by performing "second line" assays. We reviewed the diagnostic pitfalls of the cases under study and provide some guidance for alternative tests when facing a prolonged aPTT that may have a double meaning.
authors.affiliation: Haemostasis & Thrombosis Department, William Harvey Research Institute, Charterhouse Square, London, United Kingdom Haemostasis & Thrombosis Department, St George's Hospital, London, United Kingdom paxmes@aol.com.
authors.forename: Paul R J
authors.initials: PR
authors.lastname: Ames
authors.affiliation: Dipartimento di Medicina Molecolare e Biotecnologie Mediche - Università degli Studi di Napoli Federico II - VIa Pansini, Napoli, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Graf
authors.affiliation: Haemostasis & Thrombosis Department, St George's Hospital, London, United Kingdom.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Archer
authors.affiliation: Dipartimento di Medicina Molecolare e Biotecnologie Mediche - Università degli Studi di Napoli Federico II - VIa Pansini, Napoli, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Scarpato
authors.affiliation: Chemical Pathology Department, A. Cardarelli Hospital, Naples, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Iannaccone
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005169:Factor VIII / Q000037:antagonists & inhibitors* / Q000378:metabolism; D005260:Female; D006801:Humans; D016682:Lupus Coagulation Inhibitor / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010314:Partial Thromboplastin Time / Q000379:methods
chemical_list: D016682:Lupus Coagulation Inhibitor; C078147:F8 protein, human; D005169:Factor VIII
keywords: acquired hemophilia; lupus anticoagulant