The specimen drawn for a mixing study must meet the following conditions for accurate testing:
- A properly filled 3.2% sodium citrate tube (as shown in the image on the right) must be collected.
- Proper centrifugation to create platelet-poor plasma for analysis must occur; the presence of platelet phospholipids can interfere with the mixing study if an antiphospholipid antibody is present.
- Testing must be performed within four hours of collection.