Summary & Overview
CPT 0257U: VLCAD Enzyme Activity Assay, Blood (MS/MS)
CPT code 0257U is a Proprietary Laboratory Analyses (PLA) code that identifies a single, manufacturer‑ or lab‑specific test: Very–Long Chain Acyl–CoA Dehydrogenase (VLCAD) Enzyme Activity measured in leukocytes from a blood specimen using tandem mass spectrometry (MS/MS). The assay supports diagnosis and management of VLCAD deficiency, a potentially life‑threatening disorder of fatty‑acid oxidation, making the code important for rare disease detection and targeted treatment planning nationwide. Key payers in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the clinical purpose of the test, typical sites of service, common billing modifiers, and which payers are addressed. The publication also highlights what to expect in payer coverage patterns for proprietary laboratory assays, benchmark considerations for specialized enzymatic testing, and relevant clinical context for VLCAD deficiency. Data not available in the input for specific payer coverage policies, associated taxonomies, and ICD‑10 diagnoses are noted as unavailable. This summary is intended for national audiences involved in clinical laboratory operations, medical billing, and health policy related to rare metabolic disease testing.
Billing Code Overview
CPT code 0257U is a Proprietary Laboratory Analyses (PLA) code for Very–Long Chain Acyl–CoA Dehydrogenase (VLCAD) Enzyme Activity, performed by the Children’s Hospital Colorado Laboratory on a blood specimen. The test measures VLCAD enzyme activity in leukocytes using tandem mass spectrometry (MS/MS) to aid in diagnosis and treatment planning for VLCAD deficiency, a severe fatty–acid metabolism disorder.
Service type: Laboratory — specialized biochemical enzyme assay
Typical site of service: Clinical laboratory / reference laboratory (blood specimen collection typically in an outpatient or hospital setting)
Clinical & Coding Specifications
Clinical Context
A neonate or infant with abnormal newborn screening results for fatty acid oxidation disorders is referred to a metabolic genetics clinic. The patient presents with feeding intolerance, hypoglycemia, lethargy, or cardiomyopathy, or a family history of Very–Long Chain Acyl–CoA Dehydrogenase (VLCAD) deficiency. A peripheral blood sample is collected in appropriate anticoagulant tubes and sent to Children’s Hospital Colorado Laboratory for laboratory testing. The laboratory performs leukocyte isolation and uses tandem mass spectrometry (MS/MS) to measure VLCAD enzyme activity. Results are reported back to the ordering metabolic geneticist or pediatrician and are used to confirm biochemical diagnosis, guide immediate medical management (for example, dietary fat restriction and emergency care plans), and inform genetic counseling and further molecular testing of the ACADVL gene when indicated. Typical site of service is an outpatient hospital or specialized pediatric laboratory; sample collection often occurs in an outpatient clinic, newborn nursery, or inpatient pediatric unit. The service type is a specialized enzymatic diagnostic test (Proprietary Laboratory Analysis) performed by a single laboratory.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier — standard reporting | Use when no special modifier applies; report baseline PLA test. |