Test Catalog

Test Id : F8INP

Hemophilia A F8 Gene, Intron 1 and 22 Inversion Mutation Analysis, Prenatal

Useful For
Suggests clinical disorders or settings where the test may be helpful

Prenatal testing for hemophilia A when a mutation has not been identified in the family.

Genetics Test Information
Provides information that may help with selection of the correct genetic test or proper submission of the test request

Detects the common inversion mutations within the F8 gene. Approximately 50% of affected males with severe hemophilia A have been shown to have an inversion.

 

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

Reflex Tests
Lists tests that may or may not be performed, at an additional charge, depending on the result and interpretation of the initial 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
_STR1 Comp Analysis using STR (Bill only) No, (Bill only) No
_STR2 Add'l comp analysis w/STR (Bill Only) No, (Bill only) No

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

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

 

The following algorithms are available in Special Instructions:

-Hemophilia Carrier Testing Algorithm

-Hemophilia Testing Algorithm

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Name
A short description of the method used to perform the test

Polymerase Chain Reaction (PCR) or Inverse Shifting-Polymerase Chain Reaction (IS-PCR)

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

HA F8 Int 1/22 Inversion, AF or CVS

Aliases
Lists additional common names for a test, as an aid in searching

Hemophilia A

HA

Factor VIII gene

F8

Intron 22 inversion

Intron 1 inversion

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

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

 

The following algorithms are available in Special Instructions:

-Hemophilia Carrier Testing Algorithm

-Hemophilia Testing Algorithm

Specimen Type
Describes the specimen type validated for testing

Varies

Additional Testing Requirements

Due to the complexity of prenatal testing, consultation with the laboratory is required for all prenatal testing. Prenatal specimens can be sent Monday through Thursday and must be received by 5 p.m. CST on Friday in order to be processed appropriately. All prenatal specimens must be accompanied by a maternal blood specimen. Order MATCC / Maternal Cell Contamination, Molecular Analysis on the maternal specimen.

Shipping Instructions

Advise Express Mail or equivalent if not on courier service

Necessary Information

Hemophilia A 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
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Results will be reported and also 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 (T329).

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.

 

Specimen Type: Chorionic villi

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 (T095).

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

 

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: There will be no culture charge.

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Forms

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

Amniotic fluid: 10 mL

Chorionic Villi: 5 mg

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Varies Varies (preferred)

Useful For
Suggests clinical disorders or settings where the test may be helpful

Prenatal testing for hemophilia A when a mutation has not been identified in the family.

Genetics Test Information
Provides information that may help with selection of the correct genetic test or proper submission of the test request

Detects the common inversion mutations within the F8 gene. Approximately 50% of affected males with severe hemophilia A have been shown to have an inversion.

 

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

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

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

 

The following algorithms are available in Special Instructions:

-Hemophilia Carrier Testing Algorithm

-Hemophilia Testing Algorithm

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Hemophilia A (HA) is due to a deficiency of clotting factor VIII (FVIII). HA is an X-linked recessive bleeding disorder that affects approximately 1 in 5,000 males. Males are typically affected with bleeding symptoms, whereas carrier females generally do not have bleeding symptoms but are at risk of having affected sons. Rarely, approximately 10% of carrier females have FVIII activity levels below 35% and are at risk for bleeding.

 

Bleeding, the most common clinical symptom in individuals with HA, correlates with FVIII activity levels. FVIII activity levels of <1% are associated with severe disease, 1% to 5% activity with moderate disease, and 5% to 40% with mild disease. In males with severe deficiency, spontaneous bleeding may occur. In individuals with mild HA, bleeding may occur only after surgery or trauma.

 

FVIII is encoded by the factor VIII (F8) gene. Approximately 98% of patients with a diagnosis of HA are found to have a mutation in F8 (ie, intron 1 and 22 inversions, point mutations, insertions, and deletions). The intron 1 and 22 inversion mutations account for approximately 50% of mutations associated with severe HA. These inversions are typically not identified in patients with mild or moderate HA.

 

It is recommended that the F8 mutation be confirmed in the affected male or obligate carrier female prior to testing at-risk individuals. Affected males are identified by FVIII activity (F8A / Coagulation Factor VIII Activity Assay, Plasma) and clinical evaluation, while obligate carrier females are identified by family history assessment. If the intron inversion assays do not detect an inversion in these individuals, additional analysis (ie, F8 sequencing) may be able to identify the familial mutation. Of note, not all females with an affected son are germline carriers of a F8 mutation, as de novo mutations in F8 do occur. Approximately 20% of mothers of isolated cases do not have an identifiable germline F8 mutation. Importantly, there is a small risk for recurrence even when the familial F8 mutation is not identified in the mother of the affected patient due to the possibility of germline mosaicism.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Not applicable

Interpretation
Provides information to assist in interpretation of the test results

An interpretive report will be provided.

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Obtaining a medical genetics or hematology (coagulation) consultation prior to ordering is advisable. Molecular genetic or hemophilia center consultation is available for all possible hemophilia A cases and is particularly indicated in complex cases or in situations in which the diagnosis is atypical or uncertain.

 

This assay detects only F8 intron 1 and 22 inversion mutations. Thus, a negative result does not exclude the presence of other mutations in F8.

 

The intron 1 and 22 inversion mutations targeted by this assay are found in approximately 50% of individuals with severe hemophilia A; the assay may be uninformative for a number of families.

 

Test results should be interpreted in the context of clinical findings, family history, and other laboratory data. Errors in our interpretation of results may occur if information given is inaccurate or incomplete.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

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;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;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;96(8):2905-2906

5. Pruthi RK: Hemophilia: A Practical Approach to Genetic Testing. Mayo Clin Proc 2005;80:1485-1499

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Description
Describes how the test is performed and provides a method-specific reference

Genomic DNA from whole blood or cord blood is digested with Ksp 22 I restriction enzyme, ligated with T4 DNA ligase, and amplified by PCR with primers specific for the F8 intron 22 inversion mutations.(Rosetti LC, Radic CP, Larripa IB, De Brasi CD: Developing a new generation of tests for genotyping hemophilia-causative rearrangements involving int22h and int1h hotspots in the factor VIII gene. J Thromb Haemost 2008;6:830-836)

 

Genomic DNA from whole blood or cord blood is amplified by PCR with primers specific for the F8 intron 1 inversion mutation.(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)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Friday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

28 to 35 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

Extracted DNA indefinitely, patient must opt-out.

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

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
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

81403

LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

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
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
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

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports