Chromogenic Factor VIII Inhibitor ()
Department: Coagulation
Test Synonym(s): LAB6349, ChROM FVIII IN, Chromogenic F8 Inhibitor
CPT Codes: 85335
Methodology: Chromogenic
Reference Range: 0 Niejmegen Bethesda Units (NBU)
Tube Type: Two 2.7mL Light blue top - 3.2% Sodium Citrate
Specimen: Citrated platelet poor plasma - Requires double centrifugation if sending a plasma aliquot. Aliquot(s) must be frozen if not received by lab within 4 hours of collection.
Alternate Specimen: None
Pediatric Requirements: Pediatric: Two 2.7mL Light blue top - 3.2% Sodium Citrate. Neonatal: Two 1.8mL Light blue top - 3.2% Sodium Citrate.
Volume: 2.0 mL
Minimum Volume: 1.0 mL
Temperature: Room Temperature for Light blue top tube, must be received within 4 hours of draw. Plasma aliquot(s) must be frozen if not received by lab within 4 hours of collection.
Stability: Room temperature: 4 hours; Frozen (-70 C): 1 month
Reasons for Rejection: Clotted sample, incorrectly filled tubes, incorrect tube type, grossly hemolyzed sample, grossly lipemic sample, grossly icteric sample, whole blood >4.0 hours old
Days Performed: Monday - Friday
Times Performed: 8:00 AM - 2:00 PM. Tests requested after hours or on holidays have to be approved by the Medical Director on call.
TAT: 1 - 3 days
Significance: The Chromogenic Factor VIII inhibitor assay is used to monitor the development of a factor VIII inhibitor in patients receiving HemlibraŽ. The appropriate test is 8In, LAB3441.
Special Instructions: The Chromogenic Factor VIII activy inhibitor assay is used to monitor the development of a Factor VIII inhibitor in patients receiving HemlibraŽ. The assay is not intended for monitoring inhibitors in patients on traditional factor replacement therapy or an acquired factor VIII inhibtor. The appropriate test is 8IN, LAB3441. Indwelling line should be flushed with saline and 5.0 mL of blood discarded before collecting samples for coagulation assays. Tube must be full and not clotted. Deliver to lab immediately. Samples received from an outside lab must be aliquoted and frozen. Indwelling line should be flushed with saline and 5.0 mL of blood discarded before collection samples for coagulation assays. The tube must be full and not clotted. Deliver to lab immediately. Samples received from an outside lab must be aliquoted and frozen. Samples aliquoted for shipping must be double centrifuged prior to freezing. Grossly hemolyzed, icteric, or lipemic samples may be rejected.
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