CPT® Code 81173

Official Description

AR (androgen receptor) (eg, spinal and bulbar muscular atrophy, Kennedy disease, X chromosome inactivation) gene analysis; full gene sequence

Common Language Description

The CPT® Code 81173 pertains to the analysis of the androgen receptor (AR) gene, which is crucial for understanding various genetic conditions associated with androgen inactivation syndrome, spinal and bulbar muscular atrophy, Kennedy disease, androgenetic alopecia, and polycystic ovarian syndrome. This molecular genetic testing involves a comprehensive examination of the full gene sequence of the AR gene, located on the long (q) arm of the X chromosome at position 12 (Xq12). The AR gene encodes a protein that binds to androgen hormones, such as testosterone, and plays a significant role in regulating the development of male characteristics during both gestation and puberty. The normal function of the AR gene is characterized by a specific range of trinucleotide CAG (cytosine-adenine-guanine) repeats, typically less than 10 to about 36. However, in conditions like spinal and bulbar muscular dystrophy, these CAG repeats can be expanded to 38 or more, leading to symptoms such as progressive muscle wasting, gynecomastia, testicular atrophy, and fertility issues, predominantly affecting males aged 30 to 60. Mutations in the AR gene can manifest in various ways, including single base pair changes, insertions or deletions of multiple base pairs, or alterations that affect the androgen binding site, resulting in conditions like androgen insensitivity syndrome, which can lead to male feminization. Additionally, small mutations in the AR gene are implicated in androgenetic alopecia, causing hair loss in both males and females. Women with AR gene mutations may also experience symptoms of polycystic ovarian syndrome, including hirsutism, acne, and fertility challenges. The analysis performed under CPT® Code 81173 is essential for identifying functional variants within the AR gene by comparing gene segments to detect similarities or differences, which aids in understanding the genetic underpinnings of these conditions. This comprehensive gene analysis is distinct from other codes, such as 81204, which focuses on allele characterization, and 81174, which targets specific exon sequences for known familial variants.

1. Indications

The AR gene analysis performed under CPT® Code 81173 is indicated for the following conditions and symptoms:

Androgen Inactivation Syndrome - A condition where the body is unable to respond to androgens, leading to various developmental issues.
Spinal and Bulbar Muscular Atrophy - A neuromuscular disorder characterized by progressive muscle weakness and atrophy, particularly affecting muscles close to the trunk and those of the face and throat.
Kennedy Disease - A genetic disorder that affects motor neurons, leading to muscle weakness and atrophy, often accompanied by gynecomastia and testicular atrophy.
Androgenetic Alopecia - A common form of hair loss in both men and women, associated with mutations in the AR gene.
Polycystic Ovarian Syndrome - A hormonal disorder in women that can lead to irregular menstrual cycles, hirsutism, acne, and fertility issues, potentially linked to AR gene alterations.

2. Procedure

The procedure for CPT® Code 81173 involves several key steps to ensure a comprehensive analysis of the AR gene:

Step 1: Sample Collection - A biological sample, typically blood or saliva, is collected from the patient to obtain DNA for analysis.
Step 2: DNA Extraction - The DNA is extracted from the collected sample using standardized laboratory techniques to ensure purity and integrity for subsequent analysis.
Step 3: Full Gene Sequencing - The full sequence of the AR gene is analyzed using advanced molecular genetic testing methods, such as next-generation sequencing, to identify any mutations or variations present in the gene.
Step 4: Data Comparison - The sequenced data is compared against known reference sequences to identify functional variants, including point mutations and single nucleotide polymorphisms (SNPs).
Step 5: Interpretation of Results - The results are interpreted to determine the presence of any pathogenic variants that may be associated with the aforementioned conditions, providing valuable information for diagnosis and potential treatment options.

3. Post-Procedure

After the completion of the AR gene analysis under CPT® Code 81173, the following post-procedure considerations are important:

Patients may receive genetic counseling to discuss the implications of the test results, especially if pathogenic variants are identified. This counseling can help patients understand their condition, potential health risks, and the impact on family members. Additionally, follow-up testing or monitoring may be recommended based on the findings, particularly for conditions like spinal and bulbar muscular atrophy or polycystic ovarian syndrome. It is also essential for healthcare providers to document the results accurately in the patient's medical record to ensure continuity of care and appropriate management of any identified conditions.

Short Descr	AR GENE FULL GENE SEQUENCE
Medium Descr	AR GENE ANALYSIS FULL GENE SEQUENCE
Long Descr	AR (androgen receptor) (eg, spinal and bulbar muscular atrophy, Kennedy disease, X chromosome inactivation) gene analysis; full gene sequence
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.