CPT® Code 81170

Official Description

ABL1 (ABL proto-oncogene 1, non-receptor tyrosine kinase) (eg, acquired imatinib tyrosine kinase inhibitor resistance), gene analysis, variants in the kinase domain

Common Language Description

The CPT® Code 81170 pertains to the molecular genetic testing of the ABL1 gene, specifically focusing on the analysis of variants within the kinase domain. The ABL1 gene is located on the q arm of chromosome 9 at position 34.1 and encodes a protein that functions as a non-receptor tyrosine kinase. This protein plays a critical role in various cellular processes, including cell division, adhesion, differentiation, and the cellular response to stress. In the context of certain hematological malignancies, such as chronic myelogenous leukemia (CML) and acute lymphoblastic leukemia (ALL), patients may develop resistance to tyrosine kinase inhibitors (TKIs) like imatinib. This resistance is characterized by the loss of a previously effective response to the treatment. TKIs work by binding to the inactive form of the ABL kinase, thereby inhibiting its activity at the ATP-binding site, known as the P-loop, of the BCR-ABL fusion protein. This inhibition prevents the autophosphorylation of the kinase, maintaining the BCR-ABL tyrosine kinase in an enzymatically inactive state. However, the emergence of at least 40 known mutations associated with TKI resistance can lead to a situation where neoplastic cells no longer respond to imatinib or other next-generation TKIs. The testing for these gene variants, which may include amplifications, deletions, and point mutations, is typically performed on samples obtained from blood and/or bone marrow through procedures such as venipuncture and bone marrow aspirate. The analysis is conducted using reverse transcription-polymerase chain reaction (RT-PCR) to detect the presence of these mutations.

1. Indications

The molecular genetic testing represented by CPT® Code 81170 is indicated for the following conditions:

Chronic Myelogenous Leukemia (CML) This condition is characterized by the overproduction of myeloid cells in the bone marrow and is often associated with the BCR-ABL fusion gene, which results from a chromosomal translocation.
Acute Lymphoblastic Leukemia (ALL) This is a type of cancer that affects the lymphoid lineage of blood cells and can also involve the BCR-ABL fusion gene, leading to similar treatment challenges as seen in CML.
Acquired Imatinib Tyrosine Kinase Inhibitor Resistance This occurs when patients who have previously responded to imatinib treatment lose their response due to mutations in the ABL1 gene, necessitating genetic testing to identify specific variants that may be responsible for this resistance.

2. Procedure

The procedure for conducting the molecular genetic testing for the ABL1 gene involves several key steps:

Sample Collection Blood and/or bone marrow samples are collected from the patient. This is typically done through venipuncture for blood samples or a bone marrow aspirate for bone marrow samples. These procedures are performed to obtain the necessary biological material for testing.
Sample Preparation Once the samples are collected, they are processed to isolate the nucleic acids. This involves extracting RNA from the collected blood or bone marrow, which is essential for the subsequent analysis of gene mutations.
Reverse Transcription-Polymerase Chain Reaction (RT-PCR) The extracted RNA is then subjected to RT-PCR, a technique that converts RNA into complementary DNA (cDNA) and amplifies specific gene regions. This step is crucial for detecting the presence of mutations in the ABL1 gene's kinase domain.
Mutation Analysis The amplified cDNA is analyzed to identify any variants present in the kinase domain of the ABL1 gene. This analysis helps determine if mutations associated with TKI resistance are present, which can inform treatment decisions for the patient.

3. Post-Procedure

After the molecular genetic testing is completed, the results are typically reviewed by a healthcare professional. The findings can provide critical information regarding the presence of specific mutations in the ABL1 gene, which may influence the choice of therapy for patients with CML or ALL. Depending on the results, further treatment options may be considered, including alternative TKIs or other therapeutic strategies. Patients may also require follow-up consultations to discuss the implications of the test results and any necessary adjustments to their treatment plan. It is important to ensure that the results are communicated effectively to the patient and that any additional testing or monitoring is arranged as needed.

Short Descr	ABL1 GENE
Medium Descr	ABL1 GENE ANALYSIS KINASE DOMAIN VARIANTS
Long Descr	ABL1 (ABL proto-oncogene 1, non-receptor tyrosine kinase) (eg, acquired imatinib tyrosine kinase inhibitor resistance), gene analysis, variants in the kinase domain
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)	T2D - Other tests - other
MUE	1

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.
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.
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.
GZ	Item or service expected to be denied as not reasonable and necessary
XU	Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service