Questions and Answers about Coronavirus

DNA Hemophilia A Mutation Screen

Also Known as (Alias) HemA Genotyping; F8 Genotyping
Method Polymerase Chain Reaction (PCR) Based
Test Information Severe patients that are negative for the DNA Factor VIII inversion or patients that have moderate or mild hemophilia can be evaluated for mutations. Through our current screening methods, a mutation is found ~90-95% of the time. A reference for the DNA FVIII mutation database can be found at,, and

If the specific mutation cannot be identified, intragenic linkage is often useful to trace the affected allele through the family tree by following 5 polymorphic sites. Linkage studies also help identify the de novo origin of mutations in families with an isolated occurrence (eg: maternal grandparents). Intragenic linkage may be useful in 80-90% of families where key family members (patient and both parents of potential carrier) are available.

Additional Test Information For approximately half of the severe hemophilia A patients (and moderate cases with FVIII levels of ~1%), the DNA Factor VIII Inversion will be negative. For these patients, along with the moderate and mild patients, the Hemophilia A Mutation Evaluation will be performed to identify the mutation. A MDE (mutation detection enhancement) screen will be performed initially and if needed, will be followed by a sequence screen. Once identified, the genotype will be tested by confirmation analysis.

Confirmation is performed one of two ways. If the mutation creates/removes a restriction enzyme digestion site, the testing will be performed by RFLP. If a restriction enzyme digestion site is not present, testing will be done by sequencing the exon in which the mutation is located.

Sample Requirements EDTA (lavender top)
Requested Volume 5-10cc EDTA (lavender top) tube

Analysis of amniocytes can be performed on cultured amniocytes. Two T-25 flasks of cells cultured to confluency will be accepted. Bloodworks Northwest does not have facilities to culture amniocytes. 

Shipping Information Whole blood shipped at 4oC or ambient temperature is acceptable and should arrive in the lab within 48 hours.

Send samples to:
Bloodworks Northwest
Eastlake SDL
1551 Eastlake Ave E.
Seattle, WA 98102

For additional information, please see Ordering Information-Bleeding Disorders

Requisition Form Request for Testing Hemostasis Reference Laboratory
Transaction Code 3250-02
CPT Codes 81407
Turn around Time (analytic time) 2-4 weeks
Report/Results Fax number required to receive report

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