ARUP's Laboratory Test Directory

Hemophilia A (F8) Deletion/Duplication : 2001751
[ image for: Patient History for Hemophilia A or B Gene Testing]
Patient History for Hemophilia A or B Gene Testing
  


Mnemonic: F8 DELDUP

Ordering Recommendation: Not a first-line molecular test for detecting the causal mutation in established hemophilia A. Order to detect a causal deletion/duplication mutation in established hemophilia A if F8 gene inversion and sequence testing fails to detect a pathogenic mutation.
Methodology: Polymerase Chain Reaction/Multiplex Ligation-dependent Probe Amplification
Performed: Varies
Reported: Within 14 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 A (F8) Deletion/Duplication:
Characteristics: Severe deficiency of factor VIII clotting activity leading to spontaneous joint or deep muscle bleeding. Moderate to mild deficiency is associated with prolonged bleeding after tooth extractions, surgery, or injuries and recurrent or delayed wound healing.
Incidence: 1 in 4,000-5,000 live male births worldwide, rare in females.
Inheritance: X-linked recessive. Of simplex cases, 85 percent of mothers are carriers and 10-15 percent of boys have a de novo mutation.
Penetrance: 100 percent in males and 10 percent in females.
Cause: Deleterious F8 gene mutations.
Clinical Sensitivity: 6 percent of mutations causing severe hemophilia A and <1 percent of mild to moderate hemophilia A mutations are detected by deletion/duplication testing.
Methodology: Multiplex ligation-dependent probe amplification (MLPA) to detect large F8 coding region deletions/duplications.
Analytical Sensitivity & Specificity: 99 percent.
Limitations: Rare diagnostic errors can occur due to probe site mutations. Breakpoints for large deletions/duplications will not be determined. F8 base pair substitutions, small deletions/duplications, deep intronic, and regulatory region mutations will not be detected.



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): 81406
Cross References: F8 (Hemophilia A (F8) Deletion/Duplication) , Factor VIII (Hemophilia A (F8) Deletion/Duplication)