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Test Code F8INV Hemophilia A F8 Gene, Intron 1 and 22 Inversion Mutation Analysis, Whole Blood

Useful For

First-tier molecular testing for male patients affected with severe hemophilia A when a variant has not been identified in the family

 

Determining hemophilia A carrier status for at-risk female patients, ie, individuals with a family history of severe hemophilia A

Disease States

  • Hemophilia A

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
MATCC Maternal Cell Contamination, B Yes No

Testing Algorithm

Maternal cell contamination testing will be performed for all cord blood specimens. A maternal whole blood sample with an order for MATCC / Maternal Cell Contamination, Molecular Analysis, Varies is also required to perform this test. See Additional Testing Requirements.

 

The following algorithms are available:

-Hemophilia Carrier Testing Algorithm

-Hemophilia Testing Algorithm

Reporting Name

HA F8 Intron 1/22 Inversion, B

Specimen Type

Whole blood


Ordering Guidance


For evaluation of a patient with bleeding symptoms and no known personal history of a bleeding disorder, consider ALBLD / Bleeding Diathesis Profile, Limited, Plasma or the specific factor assays.



Additional Testing Requirements


Due to the complexity of testing non-peripheral blood, consultation with the laboratory is required for all cord blood samples. Order this test on the cord blood specimen (only 1 specimen tube required) and order MATCC / Maternal Cell Contamination, Molecular Analysis, Varies on the maternal specimen.



Necessary Information


Hemophilia A Patient Information(T712) is required. Testing may proceed without the patient information, however, the information aids in providing a more thorough interpretation. Ordering providers are strongly encouraged to fill out the form and send with the specimen.



Specimen Required


Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. Call 800-533-1710 for instructions for testing patients who have received a bone marrow transplant.

Container/Tube:

Preferred: Lavender top (EDTA)

Acceptable: Yellow top (ACD) or blue top (3.2% sodium citrate)

Specimen Volume: 4 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send whole blood specimen in original tube. Do not aliquot.


Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole blood Ambient (preferred) 7 days
  Frozen  7 days
  Refrigerated  7 days

Reject Due To

Gross hemolysis OK
Gross lipemia OK

Genetics Test Information

This test detects the common inversion variants within the F8 gene. Approximately 50% of affected male patients with severe hemophilia A have been shown to have an inversion.

 

It is recommended that the F8 inversion variant be confirmed in an affected male patient or obligate female carrier prior to testing at-risk individuals.

Day(s) Performed

Weekly

Report Available

14 to 21 days

Specimen Retention Time

Whole blood: 2 weeks; DNA: Indefinitely; from New York State: 90 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

81403

LOINC Code Information

Test ID Test Order Name Order LOINC Value
F8INV HA F8 Intron 1/22 Inversion, B 81761-9

 

Result ID Test Result Name Result LOINC Value
35760 HA F8 Int 1/22 Reason for Referral 42349-1
35761 HA F8 Intron 1/22 Inversion, B 81761-9
35762 F8INV Interpretation 69047-9
35763 HA F8 Intron 1/22 Reviewed By 18771-6

Reference Values

An interpretive report will be provided.

Forms

1. Hemophilia A Patient Information (T712) is required.

2. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

3. If not ordering electronically, complete, print, and send a Coagulation Test Request (T753) with the specimen.