Hemophilia A (F8) 2 Inversions, Fetal

Casandra

Casandra Test Code AR82103Version 1 (DRAFT)

Performing Lab

Lab ARUP LaboratoriesLab Test ID 2001755CPT Codes 81265, 81403

Hemophilia A (F8) 2 Inversions, Fetal

Also known as: F8 INV FE

Clinical Use

Order Test

Use

Hemophilia A is characterized by a deficiency of factor VIII clotting activity, which can lead to severe bleeding disorders. The ARUP test specifically detects F8 gene intron 22-A or intron 1 inversions, which are common causes of severe hemophilia A. This prenatal test is intended to help identify whether a fetus carries these specific genetic inversions known to cause hemophilia A, particularly if there is a family history of the condition. It is a crucial test for expectant parents concerned about the potential inheritance of hemophilia A in their unborn child.

Special Instructions

This test is not approved for New York state and is recommended to be submitted to a New York state-approved laboratory. Counseling and informed consent are recommended for all genetic testing, particularly for New York clients, where informed consent is mandatory. The test requires submission of both fetal and maternal samples and may necessitate additional charges for culturing techniques if minimum specimen confluence is not met.

Limitations

The assay detects only the intron 22-A and intron 1 inversions within the F8 gene. Negative results do not exclude other F8 variants that might cause hemophilia A. Additionally, rare F8 inversions with different breakpoints might not be detected. Diagnostic errors can occur due to rare sequence variations. This test does not detect variants associated with mild or moderate hemophilia A in males.

Test Details

Methodology

PCR-based

Biomarkers

Gene

Intron 22-A inversion • Mutation • Categorical (e.g., Positive / Negative / Indeterminate)

Intron 1 inversion • Mutation • Categorical (e.g., Positive / Negative / Indeterminate)

LOINC Codes

Result Codes

59266-7
66746-9
31208-2
82343-5

Result Turnaround Time

9-10 days

Specimen

Cultured Cells

Volume

Not provided

Minimum Volume

one T-25 flask at 80 percent confluence

Container

two T-25 flasks at 80 percent confluence

Collection Instructions

Transfer cultured amniocytes or cultured CVS to two T-25 flasks at 80 percent confluence. Backup cultures must be retained at the client's institution until testing is complete.