Factor VII Deficiency, F7 Gene, Next-Generation Sequencing, Varies

Casandra

Casandra Test Code MC64945Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID GNF7CPT Codes 81479, 88233, 88235, 88240

Factor VII Deficiency, F7 Gene, Next-Generation Sequencing, Varies

Clinical Use

Use

This test is useful for evaluating factor VII deficiency (FVIID) in patients with a personal or family history suggestive of FVIID. It confirms an FVIID diagnosis by identifying known or suspected disease-causing alterations in the F7 gene. It helps in determining disease-causing alterations within the F7 gene to delineate the underlying molecular defect in patients with a laboratory diagnosis of FVIID, and is used for genetic counseling purposes. It assists in prognosis and risk assessment based on genotype-phenotype correlations, and is useful for carrier testing for close family members of individuals with FVIID diagnosis.

Special Instructions

Rare Coagulation Disorder Patient Information form (T824) is required and should be sent with the specimen. For New York clients, informed consent is needed and should be documented on the request form or electronic order. Special coagulation testing for Factor VII (FVII) activity should be done prior to genetic testing. If prenatal specimen is used, it must accompany a maternal blood specimen for maternal cell contamination testing.

Limitations

Next-generation sequencing may not detect all types of genomic variants, and false-negative or false-positive results can occur. There may also be regions in the F7 gene that cannot be effectively evaluated due to technical limitations, such as regions of homology or high GC content. The test is validated to detect 95% of deletions up to 75 bp and insertions up to 47 bp, with less reliability for larger delins. It is not designed to detect low levels of mosaicism. Acquired causes of FVII deficiency should be excluded before testing, and test results need to be interpreted within clinical context.

Test Details

New York Approved