Ordering Recommendation

Most comprehensive test to confirm diagnosis or determine carrier status for F9 gene variants.

Mnemonic
F9 FGA
Methodology

Polymerase Chain Reaction/Sequencing/Multiplex Ligation-dependent Probe Amplification

Performed

Varies

Reported

28-35 days

New York DOH Approval Status
Specimens from New York clients will be sent out to a New York DOH approved laboratory, if possible.
Specimen Required
Patient Preparation
Collect

Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).

Specimen Preparation

Transport 3 mL whole blood. (Min: 2 mL)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions
Remarks
Stability

Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable

Reference Interval

By report

Interpretive Data

Background Information for Hemophilia B (F9) Sequencing and Deletion/Duplication:
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:
Pathogenic F9 gene mutations.
Clinical Sensitivity:
99 percent.
Methodology:
Bidirectional sequencing of the entire F9 coding region and intron-exon boundaries and proximal promoter; Multiplex Ligation-dependent Probe Amplification (MLPA) to detect large F9 deletions/duplications.
Analytical Sensitivity and Specificity:
99 percent.
Limitations:
Diagnostic errors can occur due to rare sequence variations. Regulatory region mutations and deep intronic mutations will not be detected. The breakpoints of large deletions/duplications will not be determined. Large deletions/duplications in exon 1 may not be detected. Mutations in genes other than F9 will not be detected.

Compliance Category

Laboratory Developed Test (LDT)

Note

N/A

Hotline History
N/A
CPT Codes

81238; 81479

Components
Component Test Code* Component Chart Name LOINC
2010495 Hemophilia B (F9) Seq, Del/Dup Spcm 31208-2
2010496 Hemophilia B (F9) Seq, DelDup Interp 38896-7
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • Christmas Disease
  • Factor IX Deficiency
Hemophilia B (F9) Sequencing and Deletion/Duplication