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Factor VIII Activity, Clotting, Reflex to Chromogenic
Test Code70050
CPT Codes
85240
Includes
If Factor VIII Activity, Clotting is ≤20, then Factor VIII Activity, Chromogenic will be performed at an additional charge (CPT code(s): 85240).
Preferred Specimen
2 mL frozen plasma (x2) collected in a 3.2% sodium citrate (light blue-top) tubes
Minimum Volume
1 mL (x2)
Instructions
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.
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.
Transport Temperature
Frozen
Specimen Stability
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen -20 °C: 14 days
Frozen -70 °C: 1 year
Refrigerated: Unacceptable
Frozen -20 °C: 14 days
Frozen -70 °C: 1 year
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Received room temperature • Received refrigerated • Received thawed • Hemolysis
Methodology
Photometric Clot Detection
Reflex: Chromogenic Assay
Setup Schedule
Set up: Wed, Sat; Report available: 2-6 days
Reference Range
Factor VIII Activity, Clotting | 50-180 % normal |
Factor VIII Activity, Chromogenic | 50-160 % normal |
Clinical Significance
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.
Performing Laboratory
Quest Diagnostics Nichols Institute-San Juan Capistrano, CA |
33608 Ortega Highway |
San Juan Capistrano, CA 92675-2042 |