aPTT (Abnormals reflex to 1:1 mix)
|Profile or Test Panel||
Abnormal PT or aPTT Reflexive Evaluation Profile
Additional assays will be performed as indicated.
Intrinsic Factor Evaluation Profile
Extrinsic Factor (abnormal PT) Evaluation Profile
Bleeding Diathesis with a Normal aPTT/PT Profile
Factor VIII Inhibitor Profile
Factor Inhibitor non-Factor VIII Profile
Fibrinolysis Evaluation Profile
Lupus Anticoagulant Profile
Abnormal result reflexes to the following tests as indicated.
von Willebrand Profile
If the aPTT is prolonged and the factor VIII is normal, this panel reflexes to an aPTT Reflexive Evaluation Profile.
|Also Known as (Alias)||PTT|
|Test Information||The activated PTT (aPTT) is a screening test that measures the clotting time of plasma after recalcification. The aPTT assesses the coagulation factors of the intrinsic and common pathways (factors XII, XI, IX, VIII, X, V, prothrombin, and fibrinogen).|
|Additional Test Information||The aPTT will be prolonged in the presence of a factor deficiency, factor inhibitor, anticoagulants and lupus anticoagulants. Shortening of the aPTT can occur as a result of coagulation factor activation due to a traumatic venipuncture, inadequately processed sample, or in the presence of elevated coagulation factors. Prolonged aPTT may be reflexive to aPTT 1:1 mix. Normal ranges are included on testing report and can be made available upon request.|
|Sample Requirements||Whole Blood: 3.2% sodium citrated (blue top) OR
|Requested Volume||Two 5 ml 3.2% sodium citrated (blue top) tubes as whole blood OR frozen plasma in 4 X 1mL aliquots in plastic tubes.|
|Minimum Volume or Pediatric Volume||Frozen Plasma: at least 0.5ml in 2 plastic tubes.|
|Sample Information||Whole blood is preferred for testing, but if it is not possible to send whole blood tubes TO ARRIVE HERE WITHIN 2 HOURS of collection, then send frozen plasma. To prepare plasma, centrifuge blue top tubes at 1500g for 15 minutes and remove the plasma and centrifuge a second time at 1500g for an additional 15 minutes. Aliquot approximately 1 ml of plasma into 4 plastic tubes, and freeze.|
|Shipping Information||Whole Blood: Send at ambient temperature (18-25°C) and must be received within the lab in less than or equal to 2 hours after collection.
Frozen Plasma: Send on dry ice.
Send samples to:
For additional information, please see Ordering Information
|Requisition Form||RFT- Hemostasis Reference Laboratory|
|Test Schedule||Monday – Friday|
|Turn around Time (analytic time)||3 Business Days|
|Report/Results||Fax number required to receive report|