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Test Code F VIII:C Factor VIII:C Assay

Aliases

Clotting Factor VIII: C Assay

Useful For

This is a one stage Factor VIII activity assay. Coagulation factors are necessary for the normal functions of the extrinsic and intrinsic coagulation systems. A deficiency of any of the factors will limit the function of the coagulation cascade. Protime (PT) based assays will be used for factors of the extrinsic coagulation system (V, VII) and the PTT for the intrinsic coagulation system (VIII, IX).

Patient Preparation

No special patient preparation required

Special Collection Instructions

Properly filled 9:1 ratio (blood to anticoagulant); 3.2% NaCitrate tube

Collection Method

Venous Draw; properly filled 9:1 ratio (blood to anticoagulant)

Container

Light Blue Sodium Citrate
 

Preferred Specimen

2.7mL Lt. Blue (3.2% NaCitrate)

Acceptable Specimens

1.8 mL Lt. Blue (3.2% NaCitrate) tube

Reference or Target Ranges

50 - 150%

Reportable Units

% (percentage)

Critical Value

Not defined for this assay

Reasons for Rejection

Hemolysis Threshold N/A
Icterus Threshold N/A
Lipemia Threshold N/A
Interfering Subtances/Other Short draws, over draws, clotted, improperly labeled, hemolyzed, lipemic or icteric samples, samples > 4 hours from collection

Specimen Stability

Ambient Plasma – 4 hours
Refrigerated (4°C to 8°C) N/A
Frozen(-70°C to -20°C) 2 weeks@ -20°C; 1 year @ -70°C

Performance Information

Days and Time Performed Batched weekly Monday-Friday unless STAT
Expected Turn Around Time Batched Monday – Friday
Stat: 4 hours
Stat Availability Yes
Performing Bench Coagulation
Methodology/Method Description Werfen ACL TOPS - Photo-optical clot-detection system

Additional Information/Important Notes

After being spun down twice, separate plasma into 2 aliquot tubes and transport to University Hospital Laboratory frozen on dry ice.

CPT Codes

85240