APTT 1:1 Mix (incubated)

Also Known as (Alias) PTT
Indications Patient with prolonged aPTT and suspected acquired factor inhibitor, particularly acquired FVIII inhibitor
Method Clottable
Test Information Reflexive test if the aPTT 1:1 mix test is abnormal and etiology unknown.
Additional Test Information If a specific inhibitor is suspected, then  a 1:1 mix (patient plasma : normal plasma) is incubated at 37°C for 60 minutes.  Then an aPTT  is repeated.
Sample Requirements Whole Blood:  3.2% Sodium Citrated (blue top)  OR
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:  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 3200-10
CPT Codes 85730
Test Schedule Monday - Friday 
Turn around Time (analytic time) 1 Business Day
Report/ Results Fax number required to receive report