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Test Code F822B Hemophilia A F8 Gene, Intron 22 Inversion Known Mutation, Whole Blood

Useful For

First-tier molecular testing for male patients affected with severe hemophilia A, when a familial intron 22 inversion has been previously identified

 

Determining hemophilia A carrier status for at-risk female patients, ie, individuals with a family history of severe hemophilia A due to F8 intron 22 inversion

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, Blood is 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 22 Inversion KM, B

Specimen Type

Whole blood


Ordering Guidance


If a familial variant has not been identified in a severely affected hemophilia A patient, order F8INV / Hemophilia A F8 Gene, Intron 1 and 22 Inversion Mutation Analysis, Whole Blood.

 

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, Blood 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 intron 22 inversion within the F8 gene. The intron 22 inversion variant accounts for approximately 45% of variants associated with severe hemophilia A.

 

Intron 22 inversion known variant analysis can only be performed for individuals when an intron 22 inversion has already been identified in the family. For testing options, see Ordering Guidance.

Reference Values

An interpretive report will be provided.

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
F822B HA F8 Intron 22 Inversion KM, B 91679-1

 

Result ID Test Result Name Result LOINC Value
35139 HA F8 Int22 KM Reason for Referral 42349-1
35007 HA F8 Intron 22 Inversion KM, B 91679-1
35008 F822B Interpretation 69047-9
35009 HA F8 Int22 KM Reviewed By 18771-6

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.