Detecting
& Confirming APL
Lupus Anticoagulant Antibodies:
1st suspected when aPTT is prolonged – this is
due to
LA binding phospholipids in reagent
Mixing studies then performed:
Normal
platelet-poor-plasma + pt plasma mixed and aPTT repeated
If aPTT corrected it is not LA
If aPTTnot corrected it may be LA
Russell’s viper venom
test performed:
Venom can activate factor X directly
but is still
dependent on phospholipids
LA confirmed if::
aPTT mixing studies are
prolonged
aPTT corrected using
high-phospholipid reagent
Inhibitors to single
factor ruled out
