Non-Correction of APTT with Mixing

• If the APTT remains elevated despite addition of control plasma, this suggests that there is an inhibitor present.
• This occurs commonly in the context of heparin, though may also occur with antiphospholipid syndrome.

• • Causes of APTT Non-Correction with Mixing

  • Heparin
  • Factor IIa inhibitors (e.g. dabigatran)
  • Lupus anticoagulant
  • Specific factor inhibitors