Questions and Answers about Coronavirus

APTT 1:1 Mix

Also Known as (Alias) PTT
Method Clottable
Test Information The aPTT is performed using a 1:1 mix of patient plasma with normal plasma. Lack of aPTT correction with the  1:1 mix indicates the presence of a coagulation inhibitor. Shortening of the aPTT upon the 1:1 mix to the normal range indicates coagulation factor deficiency or a factor inhibitor that requires incubation for detection.  If aPTT is abnormal, the testing will reflex to this test.
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. 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 iceSend 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

Your gift of blood, time or money saves lives.