• Dexcom G6
• Dexcom G7 (with standalone receiver)
• Abbott Freestyle Libre
• Abbott Freestyle Libre 2

• Tandem t:slim X2 insulin pump + Abbott Freestyle Libre or Abbott Freestyle Libre 2
• Tandem t:slim X2 insulin pump + Dexcom G6

• Minimed Guardian Connect

• Medtronic Minimed 630G + Minimed Guardian 3 CGM Sensor
• Medtronic Minimed 670G + Minimed Guardian 3 CGM Sensor
• Medtronic Minimed 770G + Minimed Guardian 3 CGM Sensor

When CGM codes are covered, the related supply allowance codes are also covered.

CGM codes - E2103 and E2102

Supply allowance codes - A4239 and A4238

The supply allowance (codes A4239 and A4238) are billed as 1 Unit of Service (UOS) per thirty (30) days. Only one (1) UOS of code A4239 or A4238 may be billed to the DME MACs at a time. Billing more than 1 UOS per 30 days of code A4239 or A4238 will be denied as not reasonable and necessary.

Because CGM supplies sometimes come as a 14-day supply kit, below is an example of billing the monthly supply allowance.

Example:

• First month - Provide three kits of supplies during month: 3 x 14-day supply = 42-day supply - Bill one supply allowance fee. Will have 12 days of supplies left over for next month
• Second month - Provide two kits of supplies during month: 2 x 14-day supply = 28-day supply - Bill one supply allowance fee. Will have 10 days of supplies left over for next month
• Third month - Provide two kits of supplies during month: 2 x 14-day supply = 28-day supply - Bill one supply allowance fee. Will have 8 days of supplies left over for next month
• Fourth month - Provide two kits of supplies during month: 2 x 14-day supply = 28-day supply - Bill one supply allowance fee. Will have 6 days of supplies left over for next month

See the Continuous Glucose Monitor: Provide Supplies for a Calendar Month MLN Connects for more details.

The supply allowance (A4239 or A4238) is billed as one unit of service per 30 days. Billing more than one unit in 30 days will be denied as not reasonable and necessary.

• A4239 - Supply allowance for non-adjunctive, non-implanted continuous glucose monitor (CGM), includes all supplies and accessories, 1month supply = 1 unit of service
• A4238 - Supply allowance for adjunctive, non-implanted continuous glucose monitor (GGM), includes all supplies and accessories
  • 1 month supply = 1 unit of service

• BGM supply HCPCS codes, A4239 or A4238 requires one of the below.
  • Beneficiary owned equipment be on file with Medicare Fee-for-service for HCPCS E0607, E2100, E2101, E2103, or E2102
    OR
  • A narrative on the claim line in item 19 of CMS-1500 Claim Form or the 2400/NTE segment of an electronic claim indicating beneficiary owned HCPCS E0607, E2100, E2101, E2103, or E2102 and its approximate purchase date
    • Example: Beneficiary owned E0607. Purchased 09/15/2021

If there is no glucose monitor in the Medicare claims history or the narrative is missing, the claim will deny as missing the equipment that requires the supply.

Resolving Denials

If a denial is received with Reason Code 16, Remark Code M124 that states: missing indication of whether the patient owns the equipment that requires the part or supply, the supplier must provide that information to Medicare to place on file. This can be accomplished by calling telephone reopening through the Supplier Contact Center and adding the information below on file.

• Beneficiary owned item HCPCS; approximate purchased month and year
  • Example: Beneficiary owned E0607. Purchased 09/15/2021

Once the beneficiary-owned item is placed on file, subsequent supply claims do not require a narrative.

Non-adjunctive CGM devices replace standard home BGMs (HCPCS codes E0607, E2100, E2101) and related supplies (HCPCS codes A4233, A4234, A4235, A4236, A4244, A4245, A4246, A4247, A4250, A4253, A4255, A4256, A4257, A4258, A4259). Claims for a BGM and related supplies, billed in addition to a non-adjunctive CGM device (code E2103) and associated supply allowance (code A4239), will be denied.

Adjunctive CGM devices do not replace a standard home BGM. The supply allowance for an adjunctive CGM (A4238) encompasses all items necessary for the use of the device and includes but is not limited to, CGM sensors and transmitters. Code A4238 does not include a home BGM and related BGM testing supplies. These items may be billed separately, in addition to code A4238. Refer to the CODING GUIDELINES section in the LCD-related Policy Article for additional information.