This is a second tier test and REQUIRES PERMISSION from ARUP's Genetic Counselor (800-242-2787, x2141) before ordering. Preferred test is Hemophilia A (F8) Sequencing and Deletion/Duplication reflex.
- Patient Preparation
- Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 1 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
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: Diagnostic errors can occur due to rare sequence variations. 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. Deletions/duplications in exon 23 will not be detected.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|Component Test Code*||Component Chart Name||LOINC|
|2001753||Hemophilia A (F8) Del/Dup Interpretation|
|2001754||F8 DELDUP Specimen|
- Factor VIII
- Hemophilia A deletion/duplication assay