APTT (Abnormals reflex to 1:1 mix)

Profile or Test Panel
 Additional assays will be performed as indicated.
Abnormal result reflexes to the following tests as indicated.


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
Method Clottable
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.
Sample Requirements Whole Blood:  3.2% Sodium Citrated (blue top)  OR
Platelet-Poor Frozen Plasma
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 3 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 (18-25C) and must be received within the lab in less than or equal to 3 hours after collection.
Frozen Plasma:  send on dry ice 

Send samples to:

Bloodworks Northwest
Attn: Hemostasis Laboratory
921 Terry Ave
Seattle, WA 98104

For additional information, please see Ordering Information
Requisition Form RFT- Hemostasis Reference Laboratory
Transaction Code 3200-05
CPT Codes 85730
Test Schedule Monday - Friday 
Turn around Time (analytic time) 1 Business Day
Report/ Results Fax number required to receive report