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HelpTest Code F8INP Hemophilia A F8 Gene, Intron 1 and 22 Inversion Mutation Analysis, Prenatal
Useful For
Prenatal testing for hemophilia A when a variant has not been identified in the family
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
If amniotic fluid is received, amniotic fluid culture for genetic testing will be added at an additional charge.
If chorionic villus specimen is received, fibroblast culture for genetic testing will be added at an additional charge.
For any prenatal specimen that is received, maternal cell contamination studies will be added. A maternal whole blood specimen is required to perform this test.
The following algorithms are available:
Special Instructions
Reporting Name
HA F8 Int 1/22 Inversion, AF or CVSSpecimen Type
VariesAdditional Testing Requirements
Due to its complexity, consultation with the laboratory is required for all prenatal testing; call 800-533-1710 to speak to a genetic counselor.
All prenatal specimens must be accompanied by a maternal blood specimen. Order MATCC / Maternal Cell Contamination, Molecular Analysis, Varies on the maternal specimen.
Shipping Instructions
Advise Express Mail or equivalent if not on courier service.
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
Results will be reported and telephoned or faxed if requested.
Submit only 1 of the following specimens:
Specimen Type: Amniotic fluid
Container/Tube: Amniotic fluid container
Specimen Volume: 5-10 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. If the culture will be performed in conjunction with chromosome analysis and alpha-fetoprotein, a total of approximately 25 mL to 30 mL will be needed for the combined studies.
Specimen Stability Information: Ambient (preferred) <24 hours/Refrigerated
Additional Information:
1. Place the tubes in a Styrofoam container.
2. Fill remaining space with packing material.
3. Unavoidably, about 1% to 2% of mailed-in specimens are not viable.
4. Bloody specimens are undesirable.
5. If the specimen does not grow in culture, you will be notified within 7 days of receipt.
6. A separate culture charge will be assessed under CULAF / Culture for Genetic Testing, Amniotic Fluid.
7. All prenatal specimens must be accompanied by a maternal blood specimen; order MATCC / Maternal Cell Contamination, Molecular Analysis, Varies on the maternal specimen.
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.
Specimen Stability Information: Refrigerated (preferred) <24 hours/Ambient
Additional Information:
1. A separate culture charge will be assessed under CULFB / Fibroblast Culture for Biochemical or Molecular Testing. An additional 3 to 4 weeks is required to culture fibroblasts before genetic testing can occur.
2. All prenatal specimens must be accompanied by a maternal blood specimen; order MATCC / Maternal Cell Contamination, Molecular Analysis, Varies on the maternal specimen.
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
Specimen Stability Information: Ambient (preferred) <24 hours/Refrigerated
Additional Information: All prenatal specimens must be accompanied by a maternal blood specimen; order MATCC / Maternal Cell Contamination, Molecular Analysis, Varies on the maternal specimen.
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Varies | ||
Reference Values
An interpretive report will be provided.
Interpretation
The interpretive report will include assay information, background information, and conclusions based on the test results.
Clinical Reference
1. Antonarakis SE, Rossiter JP, Young M, et al: Factor VIII gene inversions in severe hemophilia A: results of an international consortium study. Blood. 1995 Sep 15;86(6):2206-2212
2. Rossiter JP, Young M, Kimberland ML, et al: Factor VIII gene inversions causing severe hemophilia A originate almost exclusively in male germ cells. Hum Mol Genet. 1994 Jul;3(7):1035-1039
3. Castaldo G, D'Argenio V, Nardiello P, et al: Haemophilia A: molecular insights. Clin Chem Lab Med. 2007;45(4):450-461
4. Oldenburg J, Rost S, El-Maarri O, et al: De novo factor VIII gene intron 22 inversion in a female carrier presents as a somatic mosaicism. Blood. 2000 Oct 15;96(8):2905-2906
5. Johnsen JM, Fletcher SN, Huston H, et al: Novel approach to genetic analysis and results in 3000 hemophilia patients enrolled in the My Life, Our Future initiative. Blood Adv. 2017 May 18;1(13):824-834 doi:10.1182/bloodadvances.2016002923
6. Pruthi RK: Hemophilia: a practical approach to genetic testing. Mayo Clin Proc. 2005 Nov;80(11):1485-1499
Day(s) Performed
Monday through Friday
Report Available
28 to 35 daysPerforming 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. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
81403
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| F8INP | HA F8 Int 1/22 Inversion, AF or CVS | 82343-5 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 35161 | HA F8 Int 1/22 Reason for Referral | 42349-1 |
| 35162 | HA F8 Int 1/22 Inversion, AF or CVS | 82343-5 |
| 35163 | F8INP Interpretation | 69047-9 |
| 35164 | HA F8 Intron 1/22 Reviewed By | 18771-6 |
Specimen Minimum Volume
Amniotic fluid: See Specimen Required
Chorionic villi: 5 mg
Method Name
Polymerase Chain Reaction (PCR) or Inverse Shifting-Polymerase Chain Reaction (IS-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.