Factor VIII Activity, Clotting, Reflex to Chromogenic

70050

If Factor VIII Activity, Clotting is ≤20, then Factor VIII Activity, Chromogenic will be performed at an additional charge (CPT code(s): 85240).

2 mL frozen plasma (x2) collected in a 3.2% sodium citrate (light blue-top) tubes

1 mL (x2)

Platelet-poor plasma: Centrifuge light blue-top tube 15 minutes at approx. 1500 x 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. Do not thaw.

Note: Storage of whole blood at refrigerated temperatures prior to processing may lead to cryoprecipitate formation and falsely low Factor VIII.

Frozen

Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen -20 °C: 14 days
Frozen -70 °C: 1 year

Received room temperature • Received refrigerated • Received thawed • Hemolysis

Set up: Wed, Sat; Report available: 2-6 days

In the presence of a suspected lupus anticoagulant, the one-stage appt based assay may yield false low FVIII values consistent with "haemophilia" whereas the chromogenic assay avoids lupus anticoagulant interference and yields accurate FVIII results.