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Test Code LAB2615 Coagulation Factor VIII Activity Assay, Plasma

Additional Codes

Test Name in EPIC EPIC Test Code Mnemonic
FACTOR VIII ASSAY LAB2615 FAC8

 

Useful For/Utility

 Diagnosing hemophilia A.  Diagnosing von Willebrand disease when measured with the von Willebrand factor (VWF) antigen and VWF activity.  Diagnosing acquired deficiency states.  Investigation of prolonged activated partial thromboplastin time.  Monitoring infusions of factor VIII replacement during interventional procedures and prophylactic infusions

Methodology

Electromechanical Clot Detection

Clinical Information

Factor VIII is synthesized in the liver and, perhaps, in other tissues. It is a coagulation cofactor that circulates bound to von Willebrand factor and is part of the intrinsic coagulation pathway. The biological half-life is 9 to 18 hours (average is 12 hours).  Haemophilia A is the most common of the serious haemorrhagic diseases and is caused by a congenital deficiency in factor VIII.   Factor VIII may be decreased in von Willebrand disease. Acquired deficiency states also occur.

Specimen Requirements

Fill Blue top tube to the etched line located just below the cap of the tube.
1.  Light-blue top (3.2% sodium citrate); tube must be properly filled
2.  Short-draws, over-draws, clotted or hemolyzed specimens may yield incorrect results.

Specimen Transport Temperature

1.  Do not spin in refrigerated centrifuge.
2.  Double-centrifuged specimens are critical for accurate results - spin initial specimen, remove top 2/3 of plasma, and spin plasma again in polypropylene vial.*
3.  Aliquot top 3/4 of respun specimen and place platelet-poor plasma in polypropylene vial.*
4.  If there is a delay in transport or testing for > 4 hours, send specimen frozen.
5.  Glass vials are not acceptable for processing, transport or storage.
6.  Preferred specimen volume:  1 mL plasma
7.  Minimum specimen volume:  0.5 mL plasma
 
* 2 Aliquot labels will auto print at non-performing sites to double spin 
 

Additional Information:

1. **Do not refrigerate or freeze if patient is receiving factor VIII component therapy.**

 

Day(s) Test Set Up

Upon request (day shift only)

Performing Laboratory

Coagulation-

SMDC Clinical Lab

Fargo Hospital Lab

Test Classification and CPT Coding

85240

Reference Values

0 up to 3 Days                  105.0-329.0 % Activity

3 Days up to 31 Days       83.0-274.0 % Activity

31 Days up to 1 Year       54.0-145.0 % Activity

1 Year up to 6 Years        36.0-185.0 % Activity

6 years up to 11 Years      52.0-182.0 % Activity

11 Years up to 17 years    59.0-200.0 % Activity

Adult                                  55.0-200.0 % Activity