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Test Code NGSF9 Hemophilia B, F9 Gene, Next-Generation Sequencing, Varies


Ordering Guidance


Genetic testing for hemophilia B should only be considered in males if clinical and family history, initial coagulation screens, and factor IX (FIX) activity (F_9 / Coagulation Factor IX Activity Assay, Plasma) indicate a diagnosis of hemophilia B. Causes of acquired (non-genetic) hemophilia B should be excluded prior to genetic testing.

 

Genetic testing for hemophilia B in females should only be considered if a first-degree male relative has been diagnosed with hemophilia B, if there is a maternal family history of hemophilia B and her mother has not been excluded as a carrier, or if the patient has abnormally low FIX activity (F_9 / Coagulation Factor IX Activity Assay, Plasma).

 

For females with bleeding symptoms and no known personal or family history of hemophilia B, consider BDIAL / Bleeding Diathesis Profile, Limited or the specific factor assays.

 

Prenatal genetic testing should NOT be performed without the prior identification of a familial hemophilia alteration because diagnostic prenatal testing requires an invasive procedure that carries a small but real risk of inducing spontaneous abortion.



Additional Testing Requirements


Due to the complexity of testing nonperipheral blood, consultation with the laboratory is required for all cord blood samples. All cord blood specimens must be accompanied by a maternal blood specimen. Order this test on the cord blood specimen (only 1 sample tube required) and order MATCC / Maternal Cell Contamination, Molecular Analysis, Blood on the maternal specimen.



Shipping Instructions


1. Prenatal Specimens: Advise Express Mail or equivalent if not on courier service.

2. Prenatal specimens can be sent Monday through Thursday and must be received by 3 p.m. CST on Friday in order to be processed appropriately.

3. Blood: Ambient and refrigerated specimens must arrive within 7 days, and frozen specimens must arrive within 14 days of collection.

4. Collect and package specimen as close to shipping time as possible.



Necessary Information


Hemophilia B Patient Information is required, see Special Instructions. 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


Results will be reported and also telephoned or faxed, if requested.

 

Submit only 1 of the following specimens:

 

Specimen Type: Peripheral blood or cord blood

Container/Tube:

Preferred: Lavender top (EDTA)

Acceptable: Yellow top (ACD) or light-blue top (sodium citrate)

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send specimen in original tube.

Specimen Stability Information: Ambient (preferred) 7 days/Refrigerated 7 days/Frozen 14 days

 

Due to the complexity of prenatal testing, consultation with the laboratory is required for all prenatal testing.

 

Specimen Type: Amniotic fluid

Supplies: Refrigerate/Ambient Mailer, 5 lb (T329)

Container/Tube: Amniotic fluid container

Specimen Volume: 10-20 mL

Collection Instructions:

1. Optimal timing for specimen collection is during 14 to 18 weeks of gestation, but specimens collected at other weeks of gestation are also accepted.

2. Discard the first 2 mL of amniotic fluid.

3. Place the tubes in a Styrofoam container (T329).

4. Fill remaining space with packing material.

5. Unavoidably, about 1% to 2% of mailed-in specimens are not viable.

6. Bloody specimens are undesirable.

7. If the specimen does not grow in culture, you will be notified within 7 days of receipt.

Additional Information:

A separate culture charge will be assessed under CULAF / Amniotic Fluid Culture for Genetic Testing

Specimen Stability Information: Refrigerated (preferred) <24 hours/Ambient 24 hours

 

Specimen Type: Chorionic villi

Supplies: CVS Media (RPMI) and Small Dish (T095)

Container/Tube: 15-mL tube containing 15 mL of transport media

Specimen Volume: 20-30 mg

Collection Instructions:

1. Collect specimen by the transabdominal or transcervical method.

2. Transfer the chorionic villi specimen to a Petri dish containing transport medium.

3. Using a stereomicroscope and sterile forceps assess the quality and quantity of the villi and remove any blood clots and maternal decidua.

Additional Information:

A separate culture charge will be assessed under CULFB / Fibroblast Culture for Genetic Testing

Specimen Stability Information: Refrigerated (preferred) <24 hours/Ambient <24 hours

 

Specimen Type: Confluent cultured cells

Container/Tube: T-25 flask

Specimen Volume: 2 Flasks approximately 90% confluent

Collection Instructions: Submit confluent cultured cells from another laboratory

Additional Information: There will be no culture charge.

Specimen Stability Information: Ambient (preferred) <24 hours/Refrigerated <24 hours


Forms

1. 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 in Special Instructions:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

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

Useful For

Molecular confirmation of a clinical diagnosis of hemophilia B in affected male patients

 

Identification of the causative alteration in the F9 gene for prognostic and genetic counseling purposes

 

Helping determine hemophilia B carrier status for female patients with a family history of hemophilia B

 

Molecular prenatal confirmation of hemophilia B

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
CULAF Amniotic Fluid Culture/Genetic Test Yes No
CULFB Fibroblast Culture for Genetic Test Yes No
MATCC Maternal Cell Contamination, B Yes No

Testing Algorithm

Prenatal genetic testing is not routinely performed without the prior identification of a familial hemophilia alteration in an affected male relative or a female relative who is a confirmed carrier of the alteration. Requests for this prenatal testing without a known familial alteration are performed at the discretion of the Molecular Hematopathology Laboratory Director.

 

For any cord blood or prenatal specimen that is received, maternal cell contamination studies will be added. A maternal whole blood sample is required to perform this test.

 

If amniotic fluid is received, amniotic fluid culture for genetic testing will be added and charged separately. If chorionic villus specimen is received, fibroblast culture for genetic testing will be added and charged separately.

 

The following algorithms are available in Special Instructions:

-Hemophilia Testing Algorithm (for testing affected male patients)

-Hemophilia Carrier Testing Algorithm (for female patients with a family history of hemophilia)

Method Name

Custom Sequence Capture and Targeted Next-Generation Sequencing (NGS) followed by Polymerase Chain Reaction (PCR) and Sanger sequencing when appropriate.

Reporting Name

F9 Gene, Full Gene NGS

Specimen Type

Varies

Specimen Minimum Volume

Blood: 1 mL
Amniotic fluid: 10 mL
Chorionic villi: 20 mg
Confluent cultured cells: 2 full flasks

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Varies

Reference Values

An interpretive report will be provided.

Day(s) Performed

Varies

Report Available

21 to 28 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

81238

LOINC Code Information

Test ID Test Order Name Order LOINC Value
NGSF9 F9 Gene, Full Gene NGS 93811-8

 

Result ID Test Result Name Result LOINC Value
606399 NGSF9 Result 50397-9
606400 Alterations Detected 82939-0
606401 Interpretation 69047-9
606402 Additional Information 48767-8
606403 Method 85069-3
606404 Disclaimer 62364-5
606405 Panel Gene List 48018-6
606406 Reviewed By 18771-6