ARUP's Laboratory Test Directory

Factor VIII Activity with Reflex to Bethesda Quantitative, Factor VIII : 0030026

Mnemonic: F8 BETHR

Methodology: Clotting
Performed: Mon, Wed, Fri
(On call 24 hours for emergencies. If Factor VIII is greater than 20%, no further testing will be performed. If Factor VIII Activity is 20% or less, Bethesda Quantitative, Factor VIII will be performed.)
Reported: 1-4 days
Specimen Required: Collect:  Five 5 mL lt. blue (sodium citrate). (Min: Four 5 mL) Refer to the Hemostasis/Thrombosis Specimens section in the front of this User's Guide for specimen collection instructions.

Transport:  Two 4 mL aliquots of platelet-poor plasma, frozen. (Min: 5 mL) Submit specimens in two ARUP Standard Transport Tubes.

Pediatric Collection/Transport:  5 mL platelet-poor plasma, frozen.

Remarks:  CRITICAL FROZEN. Separate specimens must be submitted when multiple tests are ordered. For hemophiliacs: note dose, date, and time of last factor VIII concentrate infusion.

Unacceptable Conditions:  Serum.  Nonfrozen and hemolyzed specimens.

Stability:  Ambient: 4 hours; Refrigerated: 4 hours; Frozen: 2 weeks
Reference Interval:
 
Test Number Components Reference Interval
0030095Factor VIII, Activity 0-6 years: 56-191%
7-9 years: 76-199%
10-11 years: 80-209%
12-13 years: 72-198%
14-15 years: 69-237%
16-17 years: 63-221%
18 years and older: 56-191%
 Bethesda Quantitative, Factor VIII No inhibitor detected.

Note: If Factor VIII activity is 20% or less, then Bethesda Quantitative, Factor VIII will be added.
CPT Code(s): 85240 Factor VIII; if reflexed, add 85335 Bethesda Quantitative
 
 

 

 

 
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