Specimen Requirements

Submit only 1 of the following specimens:

Riverside Inpatients and Riverside Campus draw sites:

Testing must be performed within 4 hours of draw if submitting unprocessed whole blood.

Draw 3 full, light blue-top (citrate) tubes; and send citrated whole blood. Invert several times to mix blood. Forward unprocessed whole blood promptly at ambient temperature only. Do not refrigerate.

Note:  1. Gross hemolysis, lipemia, and icteric specimen may affect results.

2. The presence of heparin will cause false-positive results. Patient must be heparin free for a minimum of 12 hours prior to draw.

3. This test is only performed when patient’s APTT is above the upper limit of the normal APTT range.

4. Indicate whole blood on request form.

5. Label specimens appropriately (whole blood).

Outpatients/Outreach clients:

Plasma-Frozen

Draw 4 full, light blue-top (citrate) tubes. Spin down, remove plasma, spin plasma again, and place citrated platelet-poor plasma into 4 plastic vials each containing 1 mL. (Glass vial is not acceptable.) Pour-off vials should be no more than 2/3 full. Send specimen frozen.

Note:  1. Gross hemolysis, lipemia, and icteric specimen may affect results.

2. Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.

3. The presence of heparin will cause false-positive results. Patient must be heparin free for a minimum of 12 hours prior to draw.

4. This test is only performed when patient’s APTT is above the upper limit of the normal APTT range.

5. Indicate plasma on request form.

6. Label specimens appropriately (plasma).

NOTE: If ordered in conjuction with the PT Mixing Study,  4 aliquot tubes are required for both tests.