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HelpTest ID F12NG F12 Gene, Next-Generation Sequencing, Varies
Advisory Information
Genetic testing for factor XII deficiency typically has little clinical utility. Caution in ordering is advised.
For hereditary angioedema type III, genetic testing should only be considered when there is a documented family history of angioedema that does not respond to chronic, high-dose antihistamine therapy, normal complement studies, normal C1 inhibitor level and function, and no exposure to medications that could cause angioedema, such as angiotensin-converting enzyme (ACE) inhibitors or nonsteroidal anti-inflammatory drugs.
Shipping Instructions
Ambient and refrigerated specimens must arrive within 7 days (168 hours of draw), and frozen specimens must arrive within 14 days (336 hours of draw).
Collect and package specimen as close to shipping time as possible.
Necessary Information
Rare Coagulation Disorder 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
Submit only 1 of the following specimens:
Specimen Type: Peripheral blood
Container/Tube:
Preferred: Lavender top (EDTA)
Acceptable: Yellow top (ACD) or green top (sodium citrate)
Specimen Volume: 3 mL
Collection Instructions:
1. Invert several times to mix blood.
2. Send specimen in original tube.
Specimen Stability: Ambient (preferred)/Refrigerated/Frozen
Specimen Type: Extracted DNA
Container/Tube: 1.5- to 2-mL tube
Specimen Volume: Entire specimen
Collection Instructions:
1. Label specimen as extracted DNA and source of specimen.
2. Provide indication of volume and concentration of the DNA.
Specimen Stability: Frozen (preferred)/Refrigerated/Ambient
Forms
1. Rare Coagulation Disorder Patient Information (T824) is required, see Special Instructions. Fax the completed form to 507-284-1759.
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 in Special Instructions:
-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.
Useful For
Genetic confirmation of hereditary angioedema (HAE) type III with the identification of an alteration in the F12 gene known or suspected to cause the condition
Testing for close family members of an individual with an HAE type III diagnosis
Genetic confirmation of factor XII deficiency with the identification of an alteration in the F12 known or suspected to cause the condition
This test is not intended for prenatal diagnosis
Genetics Test Information
This test detects pathogenic alterations in the F12 gene to delineate the underlying molecular defect in a patient with a laboratory diagnosis of factor XII deficiency or hereditary angioedema with normal C1 inhibitor (FXII-HAE).
The gene target for this test is:
Gene name (transcript): F12 (GRCh37 [hg19] NM_000505)
Chromosomal location: 5q35.3
Testing Algorithm
Factor XII deficiency:
Special coagulation testing for factor XII (F_12 / Coagulation Factor XII Activity Assay, Plasma) should be performed prior to any genetic testing.
Genetic testing for factor XII deficiency may be considered if:
-Factor XII activity is reduced (less than 55% of normal)
-Acquired causes of factor XII have been excluded
Hereditary angioedema type III (FXII-HAE):
An international consortium has established a testing and diagnostic algorithm for the identification of hereditary angioedema (HAE) type III.(1)
Special Instructions
Method Name
Custom Sequence Capture and Targeted Next-Generation Sequencing (NGS) Followed by Polymerase Chain Reaction (PCR) and Sanger Sequencing When Appropriate
Reporting Name
F12 Gene, Full Gene NGSSpecimen Type
VariesSpecimen Minimum Volume
Blood: 1 mL
Extracted DNA: 100 mcL at 50 ng/mcL
concentration
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Ambient (preferred) | 7 days | |
| Frozen | 14 days | ||
| Refrigerated | 7 days |
Reference Values
An interpretive report will be provided
Day(s) and Time(s) Performed
Performed weekly, Varies
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 U.S. Food and Drug Administration.CPT Code Information
81479
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| F12NG | F12 Gene, Full Gene NGS | 94238-3 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 113068 | F12NG Result | 50397-9 |
| 113062 | Alterations Detected | 82939-0 |
| 113061 | Interpretation | 69047-9 |
| 113063 | Additional Information | 48767-8 |
| 113064 | Method | 85069-3 |
| 113065 | Disclaimer | 62364-5 |
| 113066 | Panel Gene List | 58902-8 |
| 113067 | Reviewed By | 18771-6 |