Various methodologies can be used to identify potential disease-causing gene mutations. Gene sequencing involves evaluating each DNA nucleotide along the length of a gene. Full gene sequencing is the best approach when many different mutations in the same gene can cause the disorder.

The efficiency of NGS has led to an increasing number of large, multi-gene testing panels. NGS panels are particularly well-suited to conditions caused by more than one gene or where there is considerable clinical overlap between conditions making it difficult to reliably narrow down likely causes.

This guideline applies to multi-gene panel testing, which is defined as any assay that simultaneously tests for more than one gene associated with a condition. The testing may focus on sequence variants and/or deletions/duplications of those genes. Panels vary in scope, such as:

• Panels consisting of multiple genes that are associated with one specific genetic condition (e.g. Noonan syndrome, Stickler syndrome, etc.); or
• Panels consisting of multiple genes that are associated with a symptom or non-specific presentation (e.g. epilepsy, intellectual disability, hearing loss, retinal disorders, etc.).

Coverage determinations rely on the medical necessity of the components of a panel. A panel approach to testing is most compelling when:

• Multiple genes are known to cause the same condition and a limited subset of genes does not account for the majority of disease-causing mutations.
• The clinical presentation is highly suspicious for a genetic disorder, but the constellation of findings in the personal or family history does not suggest a specific diagnosis or limited set of conditions.

Panel coding and billing should reflect the efficiency gains for the laboratory in testing multiple candidate genes simultaneously. Currently, laboratories are billing for panels in a variety of ways. When a panel approach to testing is determined to be medically necessary, the following billing guidelines will apply.

• Panel is to billed with a single panel-specific code (e.g., Genomic Sequencing Procedure or GSP) or single unit of the unlisted molecular pathology code 81479:
  • The billed amount should not exceed the list price of the test.
• Panel is to be billed with multiple procedure codes representing individual genes analyzed:
  • If a more specific code exists that adequately describes the requested panel, the panel will be redirected to the more specific code (e.g., a genomic sequencing procedure code); or
  • If no more specific code exists, the panel will be redirected to a single unit of the unlisted molecular pathology code 81479, which can be used to represent a panel in total;  or
  • If the laboratory will not accept redirection to a single code, the medical necessity of each billed component procedure will be assessed independently. Only the individual panel components that meet medical necessity criteria as a first tier of testing will be reimbursed. The remaining individual components will not be reimbursable, and
  • The billed amount should not exceed the list price of the test.

The following general principles apply:

• Broad symptom-based panels (e.g. comprehensive ataxia panel) are considered not medically necessary when a narrower panel is available and more appropriate based on the clinical findings (e.g. autosomal dominant ataxia panel).
• More than one multi-gene panel is considered not medically necessary at the same time. Multi-gene panel testing should be performed in a tiered fashion with independent justification for each panel requested.
• If more than ten units of any combination of procedure codes will be billed as part of a panel with no stated differential, the panel will be deemed excessive and is considered not medically necessary.
• Genetic testing is only necessary once per lifetime. Therefore, a single gene included in a panel or a multi-gene panel may not be reimbursed if testing has been performed previously. Exceptions may be considered if technical advances in testing demonstrate significant advantages that would support a medical need to retest.

Whole genome sequencing even when billed as a panel is considered experimental/investigational and therefore non-covered.

This guideline may not apply to multi-gene panel testing for indications that are addressed in test-specific guidelines. Please see the test-specific list of guidelines for a complete list of test-specific panel guidelines.

Note: If a panel was previously performed and an updated, larger panel is being requested, only testing for the medically necessary, previously untested genes will be reimbursable. Therefore, only the most appropriate procedure codes for those additional genes will be considered for reimbursement.

Genetic testing by multigene panels is typically an outpatient procedure which is only eligible for coverage as an inpatient procedure in special circumstances, including, but not limited to, the presence of a co-morbid condition that would require monitoring in a more controlled environment such as the inpatient setting.