2025 CPT code 81120

Analysis of common variants in the IDH1 gene, including R132H and R132C,typically used in glioma diagnosis.

Follow CPT coding guidelines for molecular pathology procedures. Refer to the specific guidelines for the interpretation and reporting component (modifier 26).

Modifiers may be applicable depending on the specific circumstances (e.g., modifier 26 for professional interpretation).

Medical necessity for IDH1 testing (81120) is typically established based on clinical suspicion of a glioma. Specific criteria may vary by payer.The test helps differentiate between glioma subtypes, influencing prognosis and treatment decisions.

The clinical responsibility lies primarily with the laboratory analyst who performs the technical aspects of the test. A physician or qualified healthcare professional may separately interpret the results and generate a report.

IMPORTANT 81121 (IDH2 gene analysis) may be used for analysis of a different isocitrate dehydrogenase gene.Modifier 26 can be added if only interpretation and reporting are performed.

In simple words: This lab test checks for common changes in a gene called IDH1, which is often involved in brain tumors. The test helps doctors understand the type and potential outcome of a brain tumor.

This CPT code encompasses the technical component of analyzing common variants within the *IDH1* (isocitrate dehydrogenase 1 [NADP+], soluble) gene. The analysis includes all steps from nucleic acid extraction (e.g., using methods like digestion and cell lysis) to amplification and detection of target genes (e.g., using nucleic acid probes).The test typically includes variants R132H and R132C, although it's not limited to these specific variants.The specimen source is usually formalin-fixed paraffin-embedded tissue. Physician interpretation is reported separately using modifier 26.

Example 1: A patient presents with a suspected glioma.A tissue sample is sent to the lab for IDH1 genetic testing (81120) to help determine the tumor grade and guide treatment decisions., Post-surgical analysis of a brain tumor reveals an inconclusive diagnosis. The pathology lab performs IDH1 testing (81120) to further characterize the tumor and refine the treatment plan. , A patient with a history of glioblastoma undergoes routine monitoring.IDH1 testing (81120) is repeated to assess for disease progression or response to therapy.

** This code is often used in conjunction with other tests to fully characterize a glioma.

  • Payment Status: Active
  • Modifier TC rule: This code primarily represents the technical component (TC).The professional component (26) should be reported separately for physician interpretation.
  • Fee Schedule : Fee schedules vary by payer and geographic location. Consult your payer's fee schedule for the most up-to-date information.
  • Specialties:Oncology, Pathology, Neurology, Neurosurgery
  • Place of Service:Hospital (Inpatient or Outpatient), Laboratory, Reference Laboratory
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