ARUP's Laboratory Test Directory

Hemophilia B (F9) Sequencing : 2001578
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Patient History for Hemophilia A or B Gene Testing
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Additional Technical Information


Mnemonic: F9 FGS

Ordering Recommendation: Order to sequence the F9 gene to identify the causal mutation in individuals with established hemophilia B or for carrier testing.
Methodology: Polymerase Chain Reaction/Sequencing
Performed: Varies
Reported: Within 21 days
Specimen Required: Collect: Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).

Specimen Preparation: Transport 3 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature: Refrigerated.

Stability (collection to initiation of testing): Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Interpretive Data: Background Information for Hemophilia B (F9) Sequencing:
Characteristics: Severe deficiency of factor IX clotting activity is associated with spontaneous joint or deep tissue bleeding. Moderate or mild deficiency is associated with prolonged bleeding after tooth extractions, surgery, or injuries and recurrent or delayed wound healing.
Incidence: 1 in 25,000 males worldwide.
Penetrance: 100 percent in males and 10 percent in females.
Inheritance: X-linked recessive.
Cause: Deleterious F9 gene mutations.
Clinical Sensitivity: 97 percent.
Methodology: Bidirectional sequencing of the entire F9 coding region and intron-exon boundaries and proximal promoter.
Analytical Sensitivity and Specificity: 99 percent.
Limitations: Rare diagnostic errors can occur due to primer site mutations. Deep intronic mutations and gene duplications will not be detected in patients of either sex; large deletions will not be detected in females.



Counseling and informed consent are recommended for genetic testing. Consent forms are available online at www.aruplab.com.

See Compliance Statement C: www.aruplab.com/CS
CPT Code(s): 81405
Cross References: Christmas Disease (Hemophilia B (F9) Sequencing) , F9 (Hemophilia B (F9) Sequencing) , Factor IX Sequencing (Hemophilia B (F9) Sequencing)