Summary & Overview
HCPCS B4157: Enteral Formula for Inherited Metabolic Disorders, Nutritionally Complete
HCPCS Level II code B4157 covers nutritionally complete enteral formulas specifically designed for patients with inherited metabolic disorders. These specialty formulas deliver proteins, fats, carbohydrates, vitamins, and minerals (and may include fiber) through an enteral feeding tube, and are billed in units where 100 calories equals 1 unit. The code is important nationally because it captures the provision and reimbursement of targeted metabolic nutrition that supports patient stability, growth, and management of rare metabolic conditions.
Key payers included in this review are Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise treatment of clinical context for use of specialized enteral formulas, the typical sites of service (home and ambulatory/facility tube-feeding settings), and the billing metric for units. The publication outlines common modifiers and payer practices where available, and highlights benchmarking and policy considerations relevant to coverage of metabolic enteral nutrition.
This summary is intended for clinicians, billing professionals, and policy analysts seeking a clear reference for HCPCS Level II code B4157, including coding definition, service context, and what to expect in payer interactions and documentation requirements. Data not available in the input is noted where applicable.
Billing Code Overview
HCPCS Level II code B4157 describes an enteral formula that is nutritionally complete and formulated for special metabolic needs related to inherited metabolic disorders. The formula includes proteins, fats, carbohydrates, vitamins, and minerals, may include fiber, and is intended for administration through an enteral feeding tube. Billing is measured in units where 100 calories = 1 unit.
Service Type: Enteral nutrition therapy for inherited metabolic disease
Typical Site of Service: Home or facility-based enteral feeding via enteral access (e.g., nasogastric, gastrostomy) or other ambulatory settings where tube feeding is provided
Data not available in the input.
Clinical & Coding Specifications
Clinical Context
A 6-year-old child with a diagnosed inherited disorder of amino acid metabolism presents after genetic confirmation of phenylketonuria (PKU) and requires lifelong specialized enteral nutrition. The patient has poor oral intake and is managed at home with a gastrostomy tube placed during a prior hospitalization. The multidisciplinary workflow includes the metabolic specialist or pediatrician prescribing B4157 — an enteral formula formulated for special metabolic needs — with the prescription specifying caloric goals (e.g., 1,200 kcal/day = 12 units), macronutrient restrictions, and vitamin/mineral adjustments. A registered dietitian conducts initial caloric calculations and feeding regimen education with the caregiver, including tube feeding schedules, pump settings, and storage instructions. Durable medical equipment suppliers dispense the formula and bill payors using B4157 per unit (100 calories = 1 unit). Home health nursing may perform intermittent tube site checks and training reinforcement. Ongoing follow-up visits with the metabolic clinic assess growth parameters, plasma amino acid levels, and tolerance; formula adjustments are documented and prior authorization updates are submitted to payors as needed.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | Default - No modifier |