81406

Molecular Pathology Procedure, Level 7

CPT code 81406 represents a Level 7 molecular pathology procedure, which is part of the Tier 2 molecular pathology hierarchy. Tier 2 codes are used to report molecular pathology procedures that are not specifically listed in Tier 1 (codes 81105-81383) but require a specific level of technical and interpretive effort. Level 7 is characterized by a high degree of complexity, often involving the full gene sequence analysis of large or complex genes, or the identification of multiple mutations in a single gene where the technical work exceeds that of lower-tier levels. These procedures typically involve DNA or RNA analysis to identify germline or somatic variations associated with hereditary conditions, oncological markers, or pharmacogenetic response. Examples of genes typically reported under Level 7 include full gene sequencing for APC (adenomatous polyposis coli) for familial adenomatous polyposis, BRCA1 and BRCA2 for hereditary breast and ovarian cancer syndrome (when not using a more specific genomic sequence analysis panel), CFTR for cystic fibrosis, and FBN1 for Marfan syndrome. The process involves high-complexity laboratory techniques such as Next-Generation Sequencing (NGS), Sanger sequencing, or Multiplex Ligation-dependent Probe Amplification (MLPA). The reporting of these codes requires the laboratory to perform the technical component of the test, bioinformatic analysis to identify variants, and a clinical interpretation of the findings relative to the patient's medical history and the specific gene being analyzed. Because these codes represent a broad array of potential tests, specific documentation of the gene analyzed is required for reimbursement and clinical tracking.

Clinical Indications

  • Suspected hereditary cancer syndromes (e.g., Familial Adenomatous Polyposis, Lynch Syndrome)
  • Diagnostic confirmation of Cystic Fibrosis when Tier 1 mutation panels are inconclusive
  • Evaluation for Marfan syndrome or related connective tissue disorders via FBN1 sequencing
  • Identification of germline mutations in BRCA1/BRCA2 in patients with a high risk of hereditary breast and ovarian cancer
  • Diagnosis of Duchenne or Becker Muscular Dystrophy through DMD gene analysis
  • Screening for mutations in the PTEN gene for Cowden syndrome
  • Assessment of VHL gene mutations for von Hippel-Lindau syndrome
  • Evaluation of the RET proto-oncogene for Multiple Endocrine Neoplasia (MEN) type 2

Procedure Steps

  1. Collection of biological specimen, typically peripheral blood in EDTA tubes or formalin-fixed paraffin-embedded (FFPE) tissue.
  2. Extraction and purification of genomic DNA or RNA using automated or manual chemical lysis and column-based methods.
  3. Assessment of nucleic acid quality and quantification using spectrophotometry or fluorometry.
  4. Preparation of sequencing libraries, including fragmentation, adapter ligation, and PCR amplification if utilizing Next-Generation Sequencing (NGS).
  5. Target enrichment or hybridization capture for specific genomic regions (the full sequence of the gene in question).
  6. Sequence acquisition using high-throughput platforms or capillary electrophoresis for Sanger sequencing.
  7. Bioinformatic alignment of raw sequence data against a reference human genome (e.g., hg38).
  8. Variant calling to identify single nucleotide variants (SNVs), small insertions/deletions (indels), or copy number variations (CNVs).
  9. Clinical interpretation of identified variants according to ACMG (American College of Medical Genetics and Genomics) guidelines (Pathogenic, Likely Pathogenic, VUS, etc.).
  10. Generation of a comprehensive molecular pathology report signed by a qualified pathologist or molecular geneticist.

Coding Guidelines

  • Tier 2 codes (81400-81408) should only be used if the specific analyte or gene is not listed in a Tier 1 code (81105-81383).
  • Code 81406 should be reported only once per gene analyzed, regardless of the number of variants identified within that gene.
  • If a procedure is better described by a genomic sequence analysis panel (e.g., 81432 for hereditary breast cancer), the panel code should be used instead of individual Tier 2 codes.
  • Documentation in the medical record must specify the name of the gene being tested and the clinical rationale for the high-level sequencing.
  • Do not report 81406 in conjunction with other Tier 2 codes for the same gene; choose the level that accurately reflects the complexity of the specific analysis performed.
  • When billing, some payers require the use of the specific gene name in the 'description' field of the claim or the use of a specific molecular diagnostics (MolDX) Z-code.

Associated ICD-10 Codes