HCPCS Code A4238: Supply Allowance for Adjunctive, Non-Implanted Continuous Glucose Monitor (CGM), Includes All Supplies and Accessories

Learn what correct coding guidelines, billing rules, documentation needs, and required modifiers for CGM supplies. Read the complete guide.

Use Code

Frequently asked questions

A4238 can be billed in a single claim line for a 90-day supply (3 units). Medicare contractors (DME MACs) stress that the "From" and "To" dates of service on the claim must be the same (i.e., you bill a 90-day supply on a single date, not spanned across 90 days).

No. CGM sensors, CGM transmitters, calibration solutions, and other adjunctive CGM supplies and accessories are included in A4238 and cannot be billed separately.

When billing A4238, you must include a KX or KS modifier. Use KX if the patient is insulin-treated, or KS if the patient is not. Additionally, you must use the CG modifier if the adjunctive CGM is integrated with an insulin pump and all coverage criteria for both devices are met. Finally, a KF modifier is required if the device is classified by the FDA as a Class III device.