Sign in →

Order Code F81B Hemophilia A F8 Gene, Intron 1 Inversion Known Mutation, Blood

Useful For

First-tier molecular testing for male patients affected with severe hemophilia A, when a familial intron 1 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 1 inversion

Reflex Tests

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

Testing Algorithm

For any postnatal umbilical cord blood specimen that is received, maternal cell contamination studies will be performed at an additional charge. A maternal whole blood specimen is required to perform this test. See Additional Testing Requirements.

 

For more information the following algorithms are available:

-Hemophilia Carrier Testing Algorithm

-Hemophilia Testing Algorithm

Reporting Name

HA F8 Intron 1 Inversion KM, B

Specimen Type

Whole blood


Ordering Guidance


This test should be ordered for whole blood or postnatal umbilical cord specimens when an intron 1 inversion has previously been identified in the family. For prenatal specimens order F81P / Hemophilia A F8 Gene, Intron 1 Inversion Known Mutation Analysis, Prenatal.

 

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, 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, consultation with the laboratory is required for all postnatal umbilical cord blood specimens; call 800-533-1710 to speak to a genetic counselor.

 

All postnatal umbilical cord specimens must be accompanied by a maternal blood specimen. 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.



Additional Testing Requirements


Due to the complexity of testing nonperipheral 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 allogeneic donor will interfere with testing. For information about testing patients who have received a bone marrow transplant, call 800-533-1710.

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.

3. Whole blood collected postnatal from an umbilical cord is also acceptable if approved by the laboratory. See Additional Information.

Additional Information:

1. To ensure minimum volume and concentration of DNA are met, the requested volume must be submitted. Testing may be canceled if DNA requirements are inadequate.

2. For postnatal umbilical cord whole blood specimens, maternal cell contamination studies are performed to ensure test results reflect that of the patient tested. A maternal blood specimen is required to complete maternal cell contamination studies. Order MATCC / Maternal Cell Contamination, Molecular Analysis, Varies on the maternal blood specimen under a separate order number.


Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time
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 1 inversion in the F8 gene. The intron 1 inversion variant accounts for approximately 5% of the variants associated with severe hemophilia A.

 

Intron 1 inversion known variant analysis can only be performed for individuals when an intron 1 inversion has already been identified in the family. For testing options, see Ordering Guidance.

Reference Values

An interpretive report will be provided.

Method Description

Genomic DNA from whole blood is amplified by polymerase chain reaction with primers specific for the F8 intron 1 inversion variant.(Bagnall RD, Waseem N, Green PM, Giannelli F. Recurrent inversion breaking intron 1 of the factor VIII gene is a frequent cause of severe hemophilia A. Blood. 2002;99[1]:168-174; Meijer P, Verbruggen, Spannagi M. Clotting factors and inhibitors: Assays and interpretation. In Kottke-Marchant K, ed. Laboratory Hematology Practice. Wiley Blackwell Publishing; 2012:435-446)

Day(s) Performed

Weekly

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

81403

LOINC Code Information

Test ID Test Order Name Order LOINC Value
F81B HA F8 Intron 1 Inversion KM, B 81762-7

 

Result ID Test Result Name Result LOINC Value
35137 HA F8 Int1 KM Reason for Referral 42349-1
35001 HA F8 Intron 1 Inversion KM, B 81762-7
35002 F81B Interpretation 69047-9
35003 HA F8 Int1 KM Reviewed By 18771-6

Method Name

Polymerase Chain Reaction (PCR)

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.