Summary & Overview
CPT 0318U: EpiSign Complete Methylation Microarray for Pediatric Genetic Evaluation
CPT code 0318U designates a Proprietary Laboratory Analyses (PLA) test exclusively for EpiSign Complete from Greenwood Genetic Center, a specialized methylation microarray assay performed on blood to evaluate methylation changes across 50 or more genes in pediatric patients. The test aids in diagnosing causes of developmental delay and congenital syndromic features by detecting characteristic methylation signatures. Nationally, PLA codes like 0318U matter because they identify manufacturer- or lab-specific diagnostics that can influence coverage decisions, prior authorization practices, and clinical adoption for rare or complex genetic conditions.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the clinical context and service setting, plus a summary of payer coverage considerations and common billing modifiers. The publication provides benchmarking information where available, summaries of relevant policy language, and operational details that payers and providers commonly address when processing PLA laboratory claims. It also highlights how this test fits into clinical workflows for pediatric genetic evaluation and where stakeholders typically look for medical necessity and documentation requirements.
Data not available in the input: associated taxonomies, specific ICD-10 diagnosis codes, related CPT/HCPCS, and detailed payer policy texts.
Billing Code Overview
CPT code 0318U is a Proprietary Laboratory Analyses (PLA) code that applies only to a single, specific laboratory test: EpiSign Complete from Greenwood Genetic Center. The test uses a blood specimen and analyzes pediatric patients' genetic material (whole genome) with microarray technology to assess methylation patterns across 50 or more genes. These methylation signatures can help identify causes of developmental delays and congenital features consistent with known syndromic disorders.
Service type: Laboratory — specialized genomic/methylation testing
Typical site of service: Clinical laboratory or reference diagnostic laboratory; specimen collected in an outpatient clinic or phlebotomy setting
Clinical & Coding Specifications
Clinical Context
A pediatric patient age 6 months to 5 years is referred to a genetics clinic for global developmental delay, hypotonia, and congenital dysmorphic features. The clinician obtains a detailed family and prenatal history and orders laboratory evaluation including metabolic screening and chromosomal microarray. When initial genetic testing is non-diagnostic but clinical suspicion remains for an imprinting or methylation disorder, the clinician orders the Greenwood Genetic Center EpiSign Complete methylation microarray assay. A blood specimen is collected by venipuncture in the outpatient phlebotomy suite or inpatient pediatric unit and shipped per Greenwood Genetic Center instructions. The laboratory performs methylation profiling across 50+ genes using microarray technology and returns a report indicating methylation patterns consistent with specific imprinting or Mendelian methylation disorders, uncertain significance, or negative findings. Results are reviewed in a genetics follow-up visit; findings can inform diagnosis, prognosis, cascade testing, and care planning for developmental interventions and specialist referrals.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier | Use when no modifier applies to the service billed |
22 | Increased procedural services | Use when unusually high complexity or additional work in test processing/documentation justifies increased payment |
26 | Professional component | Use if billing only the professional interpretation component separate from the lab technical component |
52 | Reduced services | Use when the test is partially reduced or limited compared with full EpiSign Complete |
53 | Discontinued procedure | Use if testing was started but terminated for patient-related or specimen issues |
62 | Two surgeons | Not commonly used for lab tests; report only if two providers share responsibility for interpretation in exceptional institutional arrangements |
78 | Return to operating room | Not applicable for typical lab testing; not routinely used |
80 | Assistant surgeon | Not applicable for this lab-based service |
82 | Assistant (when qualified resident not available) | Not applicable for lab testing |
AS | Physician assistant, nurse practitioner, or clinical nurse specialist billing | Use when an advanced practice provider performs specimen collection or documents interpretation per payer rules |
QK | No longer used (formerly modifiers for CLIA personnel) | Rarely applicable; follow current payer guidance |
QX | Ordering/referring NPI not on file with lab | Use when the ordering clinician has a separate billing arrangement requiring identification of independent laboratory services |
QY | Laboratory performing only CLIA-exempt functions | Use per payer rules when applicable to lab arrangements |
TC | Technical component | Use when billing only the laboratory technical component of the test |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
| 207Q00000X | Medical Genetics & Genomics | Clinical geneticists who interpret results and manage follow-up |
| 2080P0208X | Pediatrician | Ordering clinicians for developmental delay evaluation |
| 207RH0000X | Clinical Molecular Genetics Laboratory | Laboratory specialty performing methylation microarray testing |
| 208D00000X | Developmental-Behavioral Pediatrics | Specialists who incorporate results into developmental care plans |
| 363L00000X | Phlebotomy | Personnel performing specimen collection and handling |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
F84.0 | Autistic disorder | Autism spectrum features may overlap with methylation-related neurodevelopmental disorders and prompt methylation testing |
R62.0 | Delay in development, not elsewhere classified | Global developmental delay is a primary indication for comprehensive methylation testing |
Q87.8 | Other specified congenital malformation syndromes affecting multiple systems | Syndromic features with congenital anomalies may prompt methylation analysis for imprinting disorders |
G80.9 | Cerebral palsy, unspecified | Motor delays and hypotonia that coexist with developmental concerns can be part of the testing indication |
R62.51 | Failure to thrive in childhood | Growth abnormalities in the context of developmental delay can be associated with genetic methylation disorders |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
0318U | EpiSign Complete methylation microarray (Greenwood Genetic Center) | Proprietary PLA code for the test described; primary billed service for methylation profiling across 50+ genes |
81479 | Unlisted molecular pathology procedure | May be used historically or when no specific PLA code exists for specialized molecular tests in certain payer systems |
80502 | Drug assay, qualitative, e.g., urine, blood; chromatographic method (uncommon for this workflow) | Not directly related; included when concurrent toxicology testing is performed as part of broader workup |
99199 | Unlisted special service, procedure or report | Administrative code occasionally used for reporting non-standard professional services related to interpretation or counseling (payer dependent) |