Summary & Overview
CPT 0231U: Genomic Unity® CACNA1A Analysis
CPT code 0231U designates the Genomic Unity® CACNA1A Analysis, a proprietary laboratory assay using PCR-free whole genome sequencing to evaluate the CACNA1A gene for disease-associated variants. As a PLA code tied to a single manufacturer, this code identifies a specific, high-complexity molecular diagnostic service for neurologic indications such as ataxia, familial hemiplegic migraine, and infantile epileptic encephalopathy. Nationally, PLA codes like 0231U matter because they standardize billing for unique commercial tests and influence access, coding transparency, and payer coverage practices across commercial and public programs.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise briefing on clinical context and intended use, typical sites of service, and the role of PLA coding in lab test identification. The publication also summarizes what to expect in payer engagement and benchmarking discussions, highlights policy considerations relevant to proprietary genetic tests, and provides the clinical framing necessary for coding, claims submission, and utilization review. Data not available in the input is noted where applicable.
Billing Code Overview
CPT code 0231U is a Proprietary Laboratory Analyses (PLA) code for the Genomic Unity® CACNA1A Analysis produced by Variantyx Inc. The test evaluates the CACNA1A gene (calcium voltage–gated channel subunit alpha1 A) for variants associated with conditions such as certain ataxias, familial hemiplegic migraine, and infantile epileptic encephalopathy. The assay is performed on a blood or saliva specimen and uses a PCR-free whole genome sequencing (WGS) platform with algorithmic data analysis to detect sequence variants in the target gene.
Service type: Laboratory — genetic sequencing / molecular diagnostic test
Typical site of service: Clinical laboratory or reference genetic testing laboratory
Clinical & Coding Specifications
Clinical Context
A 7-year-old child with episodes of progressive gait instability, episodic ataxia, and brief hemiplegic migraine presents to a pediatric neurology clinic. The neurologist documents a family history of similar episodic neurological events and progressive coordination decline. After neurologic examination and brain MRI that are nondiagnostic, the clinician orders a targeted genetic test to evaluate the CACNA1A gene. A blood or saliva specimen is collected in clinic or at a phlebotomy lab and sent to Variantyx Inc. for the Genomic Unity® CACNA1A Analysis reported with 0231U. The laboratory performs PCR-free whole genome sequencing and algorithmic analysis focused on the CACNA1A gene, interprets pathogenic and likely pathogenic variants, and issues a clinical report. The final report is reviewed by the ordering neurologist to confirm diagnosis such as episodic ataxia type 2, familial hemiplegic migraine, or CACNA1A-related epileptic encephalopathy, and to guide genetic counseling and family testing. Typical sites of service include outpatient neurology clinics, pediatric specialty clinics, and outpatient specimen collection centers. The service type is a proprietary laboratory genomic analysis (Proprietary Laboratory Analysis, PLA) performed by a specialized reference laboratory.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when billing only the laboratory professional interpretation separate from the technical test if applicable and payer requires split billing. |
TC | Technical component | Use when billing only the laboratory technical component (sequencing and analysis) if split billing applies. |
59 | Distinct procedural service | Data not available in the input. |
AS | Physician assistant, nurse practitioner, or clinical nurse specialist services for assistant at surgery | Data not available in the input. |
QK | Medical direction of two, three, or four concurrent anesthesia procedures | Data not available in the input. |
QX | CRNA service with medical direction by a physician | Data not available in the input. |
QY | Medical direction of one CRNA by an anesthesiologist | Data not available in the input. |
52 | Reduced services | Use when the test performed is reduced in scope or components compared with the full-service assay and payer requires modifier to indicate reduction. |
53 | Discontinued procedure | Use if specimen was collected but testing discontinued prior to completion for documented clinical or technical reasons. |
78 | Unplanned return to the operating/procedure room by the same physician following initial procedure for a related procedure during the postoperative period | Data not available in the input. |
80 | Assistant surgeon | Data not available in the input. |
82 | Assistant surgeon (when qualified resident surgeon is not available) | Data not available in the input. |
62 | Two surgeons | Data not available in the input. |
23 | Unusual anesthesia | Data not available in the input. |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
| 207Q00000X | Pediatric Neurology | Pediatric neurologists commonly order CACNA1A testing for ataxia, hemiplegic migraine, and early-onset epilepsy. |
| 2080P0208X | Clinical Molecular Genetics Laboratory | Laboratory specialty performing genomic sequencing and interpretation. |
| 207RC0000X | Neurology | Adult neurologists evaluate episodic neurological syndromes and may order CACNA1A testing. |
| 363L00000X | Clinical Laboratory | Reference laboratories providing high-complexity genomic testing and reporting. |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
G11.3 | Other hereditary ataxia | CACNA1A pathogenic variants cause episodic and progressive hereditary ataxias; this code is used when hereditary ataxia is suspected. |
G43.4 | Hemiplegic migraine | Familial hemiplegic migraine is associated with CACNA1A variants; testing assesses causative mutations. |
G40.4 | Status epilepticus | Severe epileptic presentations including infantile epileptic encephalopathy related to CACNA1A variants may use epilepsy codes for clinical context. |
G40.9 | Epilepsy, unspecified | Used when epilepsy is present but not otherwise specified; CACNA1A testing may be ordered in unexplained early-onset epilepsy. |
R26.89 | Other abnormalities of gait and mobility | Presents in patients with ataxia and may prompt genetic evaluation including CACNA1A analysis. |
Z13.79 | Encounter for other screening for genetic and chromosomal anomalies | Used for genetic screening or family evaluation contexts when ordering targeted genetic tests. |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
0231U | Genomic Unity® CACNA1A Analysis (proprietary PLA code) | Primary test code for the proprietary CACNA1A whole genome sequencing–based analysis performed by Variantyx Inc. |
81162 | BRCA1 and BRCA2 full sequence analysis and targeted deletion/duplication analysis (next-generation sequencing) | Example of a molecular sequencing code for hereditary testing workflows; laboratories may perform other hereditary NGS panels in parallel for differential diagnoses. |
81479 | Unlisted molecular pathology procedure | Use when a molecular test lacks a dedicated code; not typically used when a PLA code like 0231U exists but may appear for unusual adjunctive assays. |
99213 | Office or other outpatient visit for the evaluation and management of an established patient, typically 15 minutes | Represents the outpatient clinic visit during which the test is ordered and results are reviewed by the clinician. |
36415 | Collection of venous blood by venipuncture | Represents specimen collection for blood-based testing when blood is used as the specimen for 0231U. |
G0008 | Administration of influenza vaccine (not directly related) | Data not relevant to this procedure but commonly present in outpatient clinics; included here only as a placeholder if vaccination and office visit coincide. |