Prolonged aPTT Thrombotic Evaluation

Test Code

19648

CPT Codes
85613, 85730

Includes

PTT-LA w/Reflex to Hexagonal Phase Confirmation
dRVVT Screen with Reflex to dRVVT Confirm and dRVVT 1:1 Mix

Reflex Criteria:
If PTT-LA Screen is prolonged (> 40 seconds), then Hexagonal Phase Confirmation will be performed at an additional charge (CPT code(s): 85598).

If the dRVVT Screen is prolonged (> 45 seconds), the dRVVT Confirmation will be performed at an additional charge (CPT code(s): 85597).

If the dRVVT Confirm is positive, a dRVVT 1:1 mix will be performed at an additional charge (CPT code(s): 85613).

If the Hexagonal Phase Confirm and DRVVT Confirm is negative, then the Prothrombin Time (PT), Thrombin Clotting Time (TCT), and Fibrinogen, will be performed at an additional charge.

Preferred Specimen

1 mL frozen platelet-poor plasma (x4) collected in 3.2% sodium citrate (light blue-top) tubes

Minimum Volume

0.5 mL (x4)

Instructions

Platelet Poor Plasma: Centrifuge light blue-top tube 15 minutes at approximately 1500 g within 60 minutes of collection. Using a plastic pipette, remove plasma, taking care to avoid the WBC/platelet buffy layer and place into a plastic vial. Centrifuge a second time and transfer platelet-poor plasma into a new plastic vial. Plasma must be free of platelets (<10,000/mcL). Freeze immediately and ship on dry ice.

Transport Temperature

Frozen

Specimen Stability

Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 14 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Specimens received room temperature • Received refrigerated • Hemolysis

Methodology
Clot Detection

Setup Schedule

Set up: Mon-Fri; Report available: 3-5 days

Reference Range

See Laboratory Report

Clinical Significance

This evaluation is for the patient with a prolonged Activated Partial Thromboplastin Time and a history of thrombosis. The investigation follows a testing algorithm with an endpoint of arriving at a final diagnosis, most commonly a Lupus Anticoagulant.

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.