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The CPT® Code 81120 pertains to the analysis of the IDH1 gene, specifically focusing on common variants such as R132H and R132C, which are associated with glioma tumors. Gliomas represent the most prevalent category of primary brain tumors, originating from glial cells that provide support and protection to neurons within the brain and spinal cord. These tumors can be classified into various types, including astrocytomas, ependymomas, and oligodendrogliomas, each with distinct characteristics and implications for treatment and prognosis. The analysis of the IDH1 gene is crucial as it plays a significant role in the metabolic processes of cells. The IDH1 gene is located on the long (q) arm of chromosome 2 at position 34, while the IDH2 gene is found on the long (q) arm of chromosome 15 at position 26.1. The enzymes produced by these genes, isocitrate dehydrogenase 1 and 2, are responsible for converting isocitrate into 2-ketoglutarate, a process that also generates NADPH, a molecule essential for cellular protection against oxidative stress. Mutations in the IDH1 and IDH2 genes disrupt the normal function of these enzymes, leading to the abnormal accumulation of D-2-hydroxyglutarate, which interferes with cell maturation and promotes the proliferation of immature cells, ultimately contributing to the development of glioma tumors. The testing process involves obtaining tumor tissue samples through a separate, reportable procedure, followed by the extraction of DNA from the tumor cells. This DNA is then amplified using polymerase chain reaction (PCR) techniques with specific primers targeting IDH1 codon 132 and IDH2 codon 172. The final step involves pyrosequencing the cell sample to detect the presence or absence of any gene mutations, providing critical information for prognosis and potential treatment strategies.
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The IDH1 gene analysis (CPT® Code 81120) is indicated for the following conditions:
The procedure for conducting the IDH1 gene analysis involves several critical steps to ensure accurate results. First, tumor tissue samples must be obtained through a separate, reportable procedure, which is essential for the subsequent analysis. Once the tissue samples are collected, DNA is extracted from the tumor cells. This extraction process is crucial as it isolates the genetic material necessary for testing. Following extraction, the DNA undergoes amplification using polymerase chain reaction (PCR) techniques. This amplification is performed with primers that are specifically designed to target IDH1 codon 132 and IDH2 codon 172, ensuring that the relevant sections of the genes are adequately represented for analysis. After amplification, the cell sample is subjected to pyrosequencing, a method that allows for the precise determination of the presence or absence of gene mutations. This step is vital as it provides the definitive results regarding the common variant mutations of the IDH1 gene, which can significantly impact the understanding and management of glioma tumors.
Post-procedure care following the IDH1 gene analysis primarily involves monitoring the patient for any potential complications related to the tissue sampling procedure. Additionally, the results of the gene analysis should be discussed with the patient in a timely manner, as they can have significant implications for treatment planning and prognosis. Healthcare providers should ensure that the findings are integrated into the overall management strategy for the patient’s glioma, considering the potential impact of IDH1 mutations on therapeutic decisions and expected outcomes. Follow-up consultations may be necessary to address any questions or concerns regarding the results and to plan further interventions based on the analysis.
| Short Descr | IDH1 COMMON VARIANTS | Medium Descr | IDH1 COMMON VARIANTS | Long Descr | IDH1 (isocitrate dehydrogenase 1 [NADP+], soluble) (eg, glioma), common variants (eg, R132H, R132C) | Status Code | Statutory Exclusion (from MPFS, may be paid under other methodologies) | Global Days | XXX - Global Concept Does Not Apply | PC/TC Indicator (26, TC) | 9 - Not Applicable | Multiple Procedures (51) | 9 - Concept does not apply. | Bilateral Surgery (50) | 9 - Concept does not apply. | Physician Supervisions | 09 - Concept does not apply. | Assistant Surgeon (80, 82) | 9 - Concept does not apply. | Co-Surgeons (62) | 9 - Concept does not apply. | Team Surgery (66) | 9 - Concept does not apply. | Diagnostic Imaging Family | 99 - Concept Does Not Apply | CLIA Waived (QW) | No | APC Status Indicator | Service Paid under Fee Schedule or Payment System other than OPPS | Type of Service (TOS) | 5 - Diagnostic Laboratory | Berenson-Eggers TOS (BETOS) | none | MUE | 1 |
| 26 | Professional component: certain procedures are a combination of a physician or other qualified health care professional component and a technical component. when the physician or other qualified health care professional component is reported separately, the service may be identified by adding modifier 26 to the usual procedure number. | 90 | Reference (outside) laboratory: when laboratory procedures are performed by a party other than the treating or reporting physician or other qualified health care professional, the procedure may be identified by adding modifier 90 to the usual procedure number. | XU | Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service | 59 | Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25. | GA | Waiver of liability statement issued as required by payer policy, individual case | GC | This service has been performed in part by a resident under the direction of a teaching physician | GZ | Item or service expected to be denied as not reasonable and necessary |
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| 2018-01-01 | Added | Code Added. |
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