Summary & Overview
CPT 81121: IDH2 (NADP+) Molecular Diagnostic Test
Headline: Newborns to oncology patients — CPT code 81121 captures technical laboratory testing for IDH2 gene variants
Lead: CPT code 81121 designates the technical component of molecular testing that detects common changes in the mitochondrial isocitrate dehydrogenase 2 (IDH2) gene. This molecular diagnostic procedure informs diagnosis and treatment selection in conditions where IDH2 mutation status is clinically relevant.
CPT code 81121 represents a targeted genetic test performed by laboratory personnel to identify IDH2 (NADP+) gene variants. The code matters nationally because molecular diagnostics increasingly guide oncology therapeutics, clinical trial eligibility, and precision medicine pathways. Insurers and Medicare routinely evaluate coverage policies and reimbursement for such tests given their impact on treatment decisions and downstream costs.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of clinical context, expected site-of-service settings, and coverage landscape considerations. The publication summarizes benchmarking and utilization patterns where available, highlights payment and coding considerations relevant to laboratories and billing staff, and outlines the clinical scenarios in which IDH2 testing is typically performed.
Data not available in the input: associated taxonomies, ICD-10 diagnoses, related codes, and payer-specific coverage rules. The content focuses on national-level code definition, clinical relevance, and payer scope.
Billing Code Overview
CPT code 81121 describes a laboratory technical procedure to detect common variants in the mitochondrial gene encoding isocitrate dehydrogenase 2 (IDH2), also known as NADP+. This service is a molecular diagnostic test performed by a laboratory analyst to identify clinically relevant genetic changes in the IDH2 gene.
Service type: Molecular pathology / clinical molecular diagnostic testing
Typical site of service: Clinical diagnostic laboratory or hospital laboratory
Clinical & Coding Specifications
Clinical Context
A patient with newly diagnosed or suspected myeloid malignancy (for example acute myeloid leukemia or myelodysplastic syndromes) is referred for molecular testing to evaluate for somatic variants in the mitochondrial isocitrate dehydrogenase 2 gene (IDH2). A typical scenario is a hematology-oncology clinic visit where the oncologist orders targeted molecular testing on a peripheral blood or bone marrow specimen to identify IDH2 hotspot mutations that impact prognosis and targeted therapy selection. The clinical workflow includes: specimen collection (blood or bone marrow), accessioning in the molecular pathology laboratory, DNA extraction, performance of the analytical assay (e.g., PCR-based allele-specific testing or next-generation sequencing panel targeting IDH2), result verification by the lab analyst and molecular pathologist, incorporation of results into the pathology report, and communication to the ordering hematologist-oncologist for treatment planning. The usual site of service is an outpatient clinic or hospital laboratory associated with a cancer center; the technical performance of the test occurs in a certified clinical molecular diagnostics laboratory.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | When billing only the professional interpretation/reporting portion (rare for fully technical molecular assays) |