PT Mixing Studies

Abbrev Code:PT1T2   
Order Code:LAB3698Order Name:PT Mixing Studies
Synonyms:INR Mixing Study
Methodology:An INR assay of patient/normal plasma mixture at 1:2 dilution
CPT Codes: 85610 x1
Turnaround Time:Performed and reported 24 hours per day.
Special Instructions:INR must be elevated for age group for the PT mixing study to be performed.
Associated Links:

Specimen Collection and Processing for Coagulation Specimens

Collection Instructions

Optimal Volume:2.7 mL (in 3 mL tube) - filled to fill line on the tube
Minimum\Peds Volume:1.8 mL (in 2 mL tube) - filled to fill line on the tube
Container:Blue Na Citrate, 3.2% - fill to fill line on tube
Collection Instructions:If the patient's hematocrit is >55%, contact laboratory to obtain a special tube.
If using a butterfly needle, a waste tube must be collected before the blue top.
After Care:If the patient has a coagulation abnormality, apply direct pressure to the puncture site for 10 minutes; apply a pressure dressing. Instruct the patient to leave the bandage on for 12 hours.
Causes for Rejection:Underfilled tubes, overfilled tubes, clotted specimens, specimens collected in 3.8% buffered citrate, specimen greater than 8 hours old or not processed appropriately within 8 hours after collection, or specimens stored in the refrigerator.

Processing and Shipping

Specimen Processing:Send whole blood or platelet poor plasma. See Associated Link for additional processing instructions.
Shipping Instructions:Ship whole blood specimens at room temperature. Whole blood specimens must arrive within 8 hours. If greater than 8 hours is required for transport, follow specimen processing instructions and ship frozen plasma on dry ice.
Test Performed at or Referral Lab Coagulation  (UMMC East Bank)


Use:To test for presence of an inhibitor.

Click HERE to Report test errors or omissions.
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