Continuous Glucose Monitor (CGM) Supply Allowance Calculator

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Glucose Monitors

Coverage

Documentation

Different Types of CGMS (Not all Inclusive)

Adjunctive or
Non-adjunctive
Stand-alone Integrated into Insulin Infusion Pump
(CGM Component is bolded)
Non-adjunctive CGMs
  • 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
Adjunctive CGMs NOT COVERED BY MEDICARE
  • Minimed Guardian Connect
(Any CGM that does not use a monitor(reader) is not covered by Medicare because without the monitor, it is not classified as DME)
  • Medtronic Minimed 630G + Minimed Guardian 3 CGM Sensor
  • Medtronic Minimed 670G + Minimed Guardian 3 CGM Sensor
  • Medtronic Minimed 770G + Minimed Guardian 3 CGM Sensor

Reviews/Audits

  • Medical Review - View notifications/findings of pre/post claim reviews completed by Noridian Medical Review

Continuous Glucose Monitors (CGM) procedure code update:

  • New HCPCS Codes (Effective for DOS on or after 01/01/2023)
    • A4239 - Supply allowance for non-adjunctive, non-implanted continuous glucose monitor (CGM), includes all supplies and accessories, 1month supply = 1 unit of service
    • E2103 - Non-adjunctive, non-implanted continuous glucose monitor or receiver
  • Deleted Codes (Effective for DOS prior to 01/01/2023)
    • K0553 - Supply allowance for therapeutic CGM device
    • K0554 - CGM receiver/monitor

Tips

Topic Details
Continuous Glucose Monitor (CGM) Supply Allowance

Billing Monthly Supply Allowance

The supply allowance (A4239 or A4238) is billed as one unit of service per 30 days or three units of service per 90 days.

  • A4239 - Supply allowance for non-adjunctive, non-implanted continuous glucose monitor (CGM), includes all supplies and accessories
    • 1 month supply = 1 unit of service
    • 2 month supply = 2 units of service
    • 3 month supply = 3 units 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
    • 2 month supply = 2 units of service
    • 3 month supply = 3 units of service

Because CGM supplies sometimes come as a 14-day supply kit, below is an example of billing the monthly supply allowance for a 1 month supply.

Example:

Fist 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.
Diabetic Supplies Used with Blood Glucose Monitor (BGM) and Continuous Glucose Monitor (CGM)
  • 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.

Continued Coverage for Continuous Glucose Monitor (CGM) The treating practitioner must conduct, and sign follow up visits for Continuous Glucose Monitor (CGM) continued coverage. As noted in the Glucose Monitors Local Coverage Determination (LCD L33822), for continued CGM coverage, every six (6) months following the initial prescription of the CGM, the treating practitioner must conduct an in-person or Medicare-approved telehealth visit with the beneficiary to document adherence to their CGM regimen and diabetes treatment plan (emphasis added). For Medicare purposes, a pharmacist is not considered a statutorily recognized treating practitioner; therefore, a pharmacist entry in a beneficiary's medical record does not meet the continued coverage requirements in the Glucose Monitors LCD. Please see the Standard Documentation Requirements Article for a clear definition of who qualifies as a treating practitioner.
Diabetic Supplies and Accessories Used with CGM E2102 or E2103

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.

Resource

Last Updated Mar 11 , 2024

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