How would you manage a patient pre-operatively with a prolonged PTT that does not correct on mixing, with lupus anticoagulant testing that is abnormal by LA-PTT only?  

Not all reagents/assays exhibit the same sensitivity (aka responsiveness) to lupus anticoagulants (LAC). In this case, there is evidence of LAC based on one assay, LA APTT. Often we see prolongation/inhibition in other assays e.g. APTT, but the phospholipid neutralization (PNP) step is not always di...