Acceptable test to confirm diagnosis or determine carrier status for F9 gene variants.
Polymerase Chain Reaction/Sequencing
Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
Transport 3 mL whole blood. (Min: 1 mL)
Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
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: Diagnostic errors can occur due to rare sequence variations. Deep intronic mutations and gene duplications will not be detected in patients of either sex; large deletions will not be detected in females.
Laboratory Developed Test (LDT)
|Component Test Code*||Component Chart Name||LOINC|
|2001580||Hemophilia B Interpretation|
|2001581||F9 FGS Specimen|
- Christmas Disease
- F9 sequencing
- Factor IX