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Laboratory Test Directory



Name Method Department Units
APTT Clot detection
Core Lab, Coagulation sec

Specimen Requirements

Platelet poor plasma

Container Type Container Size Specimen Volume

Blue plastic tube (Citrate)

2.7 mL 2.7 mL

Frozen - 2 week(s)


Blue plastic tube (Citrate)

1.8 mL 1.8 mL

Frozen - 2 week(s)

Specimen Preparation

  • Fill tubes to appropriate mark.
  • Mix by gentle inversion immediately after collection
  • Centrifuge, remove plasma/serum and freeze
  • Plasma must be platelet free

Reasons for Rejection

  • Over or under filled tube
  • Clotted specimen
  • Not received within specified time frame
  • Gross hemolysis
  • Wrong collection tube
  • Capillary specimen


APTT test can be used to monitor patients receiving Unfractionated Heparin therapy. Whole blood samples from patients receiving Unfractionated Heparin therapy must be received in the lab and centrifuged within one (1) hour of sample collection. APTT is not indicated for patients receiving Low Molecular Weight Heparin. Indicate collection method on sample. Indicate if the patient is receiving heparin therapy. Centrifuge citrate tubes according to Lab policy, remove platelet-poor plasma, pool the plasma, aliquot and freeze. Send a minimum of two (2) aliquots of plasma.


To view Recommendations for Monitoring Anticoagulant Therapy click here.

CPT Code

  • 85730