Lupus anticoagulant testing using plasma spiked with monoclonal antibodies: performance in the UK NEQAS proficiency testing programme.
We report here results from a United Kingdom National Quality Assessment Scheme (UK NEQAS) exercise in which both plasma spiked with monoclonal antibodies and plasma from a patient known to have lupus anticoagulant (LA) were distributed to 245 hemostasis laboratories with a request for them to test for possible LA using their routine screening procedure. In general, good agreement was seen in the diagnosis of samples spiked with monoclonal antibodies against beta2-glycoprotein 1 (beta2GP1) and prothrombin, the LA-positive patient sample, and a normal pooled plasma; over 87% of centers correctly identified each sample. However, methods employing platelet neutralizing procedures were associated with a higher proportion of false-negative responses with the antiprothrombin-spiked sample, and it is important to recognize that sensitivity and responsiveness of different methods may vary between artificial plasmas and different LA-positive patient plasmas.
Jennings
I
I
UK NEQAS (Blood Coagulation), Sheffield, UK. ian@coageqa.org.uk
Mackie
I
I
Arnout
J
J
Preston
F E
FE
D000465:Algorithms; D000911:Antibodies, Monoclonal / Q000737:chemistry*; D001780:Blood Coagulation Tests / Q000379:methods*; D006023:Glycoproteins / Q000737:chemistry; D006801:Humans; D007753:Laboratories / Q000592:standards*; D016682:Lupus Coagulation Inhibitor / Q000032:analysis* / Q000097:blood*; D010314:Partial Thromboplastin Time; D011516:Prothrombin / Q000737:chemistry; D011786:Quality Control; D015203:Reproducibility of Results; D013925:Thromboplastin / Q000096:biosynthesis; D013997:Time Factors; D006113:United Kingdom; D014914:Whole Blood Coagulation Time; D053482:beta 2-Glycoprotein I
D000911:Antibodies, Monoclonal; D006023:Glycoproteins; D016682:Lupus Coagulation Inhibitor; D053482:beta 2-Glycoprotein I; D011516:Prothrombin; D013925:Thromboplastin