APTT with reflex to Mixing Studies

Test Code

PTTXG

Alias/See Also

Epic: LAB326

Includes

Mixing study is performed if the PT is above the normal range.

Preferred Specimen

Specimen Type: Platelet-poor plasma
Collection Container: Light blue top (citrate)
Specimen Volume: 1 mL

Patient Preparation
Patient should be coumadin-free for 72 hours, heparin-free for 24 hours, and free from direct thrombin inhibitors (hirudin, argatroban, etc.) for 24 hours. If that patient does not meet these criteria, the mixing study tests should be cancelled due to interfering substances.

Minimum Volume

0.5 mL

Instructions

Draw blood into a light blue (sodium citrate) tube. Be sure to fill tubes completely.
Mix gently 5 to 6 times (do not over mix).
Centrifuge the sample for 10 minutes.
Using a pipette, aliquot plasma into a plastic vial being careful not disturb the buffy coat.
Centrifuge the plasma sample a second time for 10 minutes
Using a pipette, aliquot the top portion of plasma into a plastic vial. Be careful not to disturb the sediment at the bottom (leave approx. 0.25 mL of plasma at the bottom).
Label each tube as "Plasma."
Immediately freeze samples

For complete instructions, see Platelet Poor Plasma Instructions.

Transport Container

Plastic vial

Specimen Stability

Room temperature: 2 hours
Refrigerated: Unacceptable
Frozen (<-20°C): 2 weeks

Setup Schedule

Batched, as needed.

Report Available

1 day

Reference Range

See laboratory report

Performing Laboratory

Inova Laboratories

2832 Juniper Street

Fairfax, VA 22031

Last Updated: May 10, 2023
Last Review: N. Wolford, May 10, 2023

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.