CPT® Code 81309

Official Description

PIK3CA (phosphatidylinositol-4, 5-biphosphate 3-kinase, catalytic subunit alpha) (eg, colorectal and breast cancer) gene analysis, targeted sequence analysis (eg, exons 7, 9, 20)

Common Language Description

The CPT® Code 81309 pertains to the molecular genetic testing of the PIK3CA gene, which is crucial for identifying specific mutations associated with certain types of cancer, particularly colorectal and breast cancer. The PIK3CA gene is located on the long (q) arm of chromosome 3 at position 26.32 (3q26.32) and is responsible for encoding the P110 alpha (p110a) protein, which serves as the catalytic subunit of the phosphatidylinositol-4,5-biphosphate-3-kinase enzyme. This enzyme plays a significant role in various signaling pathways that regulate essential cellular processes, including growth, apoptosis (cell death), and proliferation. The targeted sequence analysis focuses on specific exons of the PIK3CA gene, namely exons 7, 9, and 20, where mutations can have implications for treatment response and prognosis in patients diagnosed with colorectal and breast cancers. The analysis involves extracting genomic DNA (gDNA) from formalin-fixed paraffin-embedded (FFPE) tissue, core needle biopsy samples, or resected tissue slides. This DNA is then amplified using polymerase chain reaction (PCR) techniques and analyzed through targeted sequencing methods, such as Sanger sequencing or next-generation sequencing, to detect mutations that may influence clinical outcomes.

1. Indications

The molecular genetic testing represented by CPT® Code 81309 is indicated for patients diagnosed with specific types of cancer, particularly:

Colorectal Cancer This type of cancer affects the colon and rectum and may exhibit mutations in the PIK3CA gene that can influence treatment options and prognosis.
Breast Cancer In breast cancer patients, mutations in the PIK3CA gene can also provide critical information regarding potential treatment responses and overall disease outlook.

2. Procedure

The procedure for conducting the molecular genetic testing of the PIK3CA gene involves several key steps:

Step 1: Sample Collection Genomic DNA (gDNA) is extracted from various tissue sources, which may include formalin-fixed paraffin-embedded (FFPE) tissue samples, core needle biopsy cells or tissue, or resected tissue slides. This step is crucial as the quality of the DNA extracted directly impacts the accuracy of the subsequent analysis.
Step 2: DNA Amplification The extracted gDNA undergoes amplification using polymerase chain reaction (PCR) techniques. This amplification process is essential to ensure that there is sufficient DNA material available for analysis, allowing for the detection of mutations present in the targeted exons.
Step 3: Targeted Sequence Analysis Following amplification, the DNA is analyzed using targeted sequencing techniques, such as Sanger sequencing or next-generation sequencing. This analysis specifically focuses on exons 7, 9, and 20 of the PIK3CA gene, where known mutations can occur. The identification of these mutations provides valuable predictive information regarding treatment response and disease prognosis.

3. Post-Procedure

After the completion of the molecular genetic testing, the results are typically reviewed and interpreted by a qualified healthcare professional. The findings can guide treatment decisions and inform the patient about their prognosis. It is essential for healthcare providers to discuss the results with the patient, including the implications of any identified mutations on treatment options and potential outcomes. Follow-up care may include additional testing or monitoring based on the results of the PIK3CA gene analysis.

Short Descr	PIK3CA GENE TRGT SEQ ALYS
Medium Descr	PIK3CA GENE ANALYSIS TARGETED SEQUENCE ANALYSIS
Long Descr	PIK3CA (phosphatidylinositol-4, 5-biphosphate 3-kinase, catalytic subunit alpha) (eg, colorectal and breast cancer) gene analysis, targeted sequence analysis (eg, exons 7, 9, 20)
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

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
XS	Separate structure, a service that is distinct because it was performed on a separate organ/structure
GW	Service not related to the hospice patient's terminal condition
GV	Attending physician not employed or paid under arrangement by the patient's hospice provider
GZ	Item or service expected to be denied as not reasonable and necessary