Medicare CGM cost per month: the A4239 allowance and your 20 percent

One unit of A4239 buys a month of sensors, not a box

Medicare does not price CGM sensors one at a time. The DME MAC policy article for glucose monitors, A52464, says the supply allowance for a CGM system (A4238 or A4239) "encompasses all items necessary for the use of the device," including sensors and transmitters. One unit of service is one month. A supplier that tries to bill sensors or transmitters on their own lines gets them denied as unbundling, so the monthly allowance is the whole supply cost Medicare recognizes.

For a non-adjunctive CGM, the kind whose readings can be used for treatment decisions without a fingerstick check, the bundle is bigger still. A4239 also includes a home blood glucose meter and its test strips, lancets, lancing device, calibration solution and batteries, if needed. LCD L33822 backs that up from the other side: claims for a meter and strips billed in addition to a non-adjunctive CGM and its supply allowance are denied. In budget terms, a person who moves from fingerstick testing to a non-adjunctive CGM stops generating separate strip and lancet claims, and the A4239 line replaces them.

The October 2026 statewide file (DMEPOS_OCT.csv, inside dme26-d.zip) lists A4239 at $273.28 without a modifier and $317.97 with KF. Under 42 CFR 414.210(a), Medicare pays 80 percent of the lesser of the supplier's actual charge or the fee schedule amount. A supplier's charge at or above the fee makes the fee the Medicare-approved amount, and your 20 percent is figured from it: $54.66 a month, or $655.92 over twelve months, without KF.

One rounding note matters once you compare paperwork. The LCD lets a supplier bill up to 3 units of the allowance per 90 days at a time, so a single claim line often shows three months. Twenty percent of a three-unit line of $819.84 is $163.97, while three single months at $54.66 add to $163.98. The figures here are per month, so they can run a cent above a three-unit line on a Medicare Summary Notice. Neither number is wrong; they are rounded at different points.

KF or no KF: the Class III modifier and what it adds

The same code carries two prices because the FDA classifies CGMs differently. Policy Article A52464 says non-adjunctive devices billed as E2103 and A4239 include both devices the FDA classifies as Class III and devices it classifies otherwise. If the device is Class III, the claims must carry the KF modifier; if it is not, they must not. Adjunctive CGMs (E2102 with supplies A4238) are all Class III, so those claims always need KF and are rejected as missing information without it. The fee schedule's readme file defines KF in one line: "Class III device."

The A4239 and A4238 amounts are the same in every state. The E2103 receiver amounts shown are the national ceiling amount, which 29 of the 53 jurisdictions in the file list, including the four non-continental areas that the file marks as not subject to the ceiling and floor; the other 24 pay less, down to $256.09 in Indiana, as the state table further down lays out. All figures come from the October 2026 statewide file and are rounded to the cent by MyCarePrice only in the 20 percent column.

The KF difference is $44.69 a month in allowed amount, which works out to $107.16 more in your 20 percent over a year of supplies. You do not choose the modifier: it follows the device's FDA classification, and the supplier is told to confirm the class with the FDA or the manufacturer before billing if unsure. What you can do is check that the modifier on your claim matches the device in your hand, because a wrong KF moves both Medicare's payment and yours.

Two other modifiers appear on every line. The policy article requires KX when the beneficiary is insulin-treated and KS when the beneficiary is not, and the KX modifier must not be used for someone treated only with oral medication. For E2103 and A4239, a CG modifier is added only when all the LCD's coverage criteria are met at the start, and later only when the continued-coverage rule is met. These modifiers do not change the fee, but a line missing the required ones can be denied, and a denied line can become your bill if you signed an Advance Beneficiary Notice for it.

The E2103 receiver: bought once, rented, or used

The receiver is billed under a different payment class from the sensors. The October 2026 file lists E2103 in category IN, inexpensive or routinely purchased. CMS's background note to the 2026 fee schedule, DMEBACK 2026, says items in that class can be purchased new or used, or rented, but total payments cannot exceed the purchase-new fee. So the receiver costs Medicare, at most, its NU amount, however it is supplied.

In a state at the ceiling, E2103 NU is $301.27, and your 20 percent is $60.25, paid once. E2103 RR, the monthly rental, is $30.13, or $6.03 a month for you. Rental stops paying when the payments reach the purchase amount: 9 months at $30.13 come to $271.17, and payment number 10 is cut to $30.10, bringing the total to $301.27. A rented receiver therefore costs about the same as a bought one; it only spreads your $60.25 across most of a year. For a Class III receiver, the same arithmetic runs 10 months at $33.44 toward $334.44, with a final payment of $0.04.

A used receiver (E2103 UE) is $225.95, or $250.83 with KF. Whether a supplier offers used, new or rental is its business choice; the fee file only sets the ceiling Medicare will recognize for each.

How long a receiver lasts on Medicare's books comes from the CY 2026 home health final rule. In setting future bid limits, CMS treated the purchase fee for the CGM receiver as covering use of the device for 5 years and divided it by 60 months. That 5-year figure is the useful-life assumption behind the five-year totals later on this page; a receiver lost, stolen or damaged sooner follows the replacement rules in 42 CFR 414.210.

The phone question, in billing terms

Many CGM users read glucose on a phone or watch. Policy Article A52464 draws a hard line here that affects the supply allowance, the larger and recurring cost. Coverage of A4238 or A4239 is available when a stand-alone receiver or an insulin pump classified as DME displays the data. It is also available when a phone, watch, tablet or laptop is used along with the durable receiver, for example when the receiver is used on some days and a phone on others, or when the receiver is used and the data also goes to a caregiver's phone.

The article then says: "If a beneficiary never uses a DME receiver or insulin infusion pump to display CGM glucose data, the supply allowance is not covered by Medicare." Smart devices themselves are not DME, are billed as A9270, and are not covered. For cost purposes, that sentence is the difference between a $54.66 monthly share and the full price of sensors. If a supplier asks how you read your data, that is why.

A year of CGM costs, before and after the deductible

The first year carries the receiver plus twelve months of allowance; later years carry the allowance alone. The table shows both, with and without KF, under two assumptions about the deductible. In the "deductible met" column, other Part B claims in the year, such as office visits, have already used up the $283.00 deductible. In the "deductible not met" column, the CGM lines are the only Part B claims all year, so they absorb the deductible first. Real years usually fall between the two.

Checked by hand for the standard device: the receiver's 20 percent is $60.25, twelve months at $54.66 are $655.92, and together they make $716.17. When the deductible is not met, the first $283.00 of allowed charges is yours in full and 20 percent applies to the rest, which lifts the year to $942.57. In a later year with no receiver line, the deductible falls on the first two months of allowance: $882.31 for the year against $655.92 when other claims have met it.

Spread over a receiver's 5-year life with the deductible met by other claims, the standard device comes to $3,339.85 in coinsurance, about $55.66 a month on average, and the Class III version to $3,882.29. Those totals hold fee schedule amounts at October 2026 levels for five years, which they will not do: CMS updates the file each quarter, and the bundled rental described below will replace the two-line structure when it starts. Treat them as a sense of scale, not a forecast.

The deductible resets every January 1 and is shared across all Part B services, which is why the column choice matters so much. The deductible and out-of-pocket guide explains how a deductible and coinsurance stack, and how Original Medicare differs from plans with an annual cap.

Sensors cost the same in every state; receivers do not

The CGM supply allowance has no geography. A4239 is $273.28 in all 53 non-rural columns of the October 2026 statewide file, from Alabama to the Virgin Islands, and A4239 KF is $317.97 in all of them. The rural columns are blank (0.00) for both codes and for E2103. The fee schedule readme explains that pattern: codes not adjusted using competitive bidding information carry amounts only in the non-rural columns. The separate file for former competitive bidding areas has no CGM rows at all.

The receiver does vary. Under DMEBACK 2026, DME amounts not adjusted with bidding data are calculated state by state and then held between a national ceiling, set at the median of the statewide amounts, and a floor at 85 percent of the median. For E2103 NU the ceiling is $301.27 and the floor $256.08. Twenty-nine jurisdictions list the $301.27 ceiling amount: AK, AZ, CA, FL, HI, IA, IL, KS, KY, LA, MI, MO, MS, ND, NE, NM, NV, NY, OH, OK, PR, SC, SD, TN, TX, UT, VI, WA, WV. Four of them (AK, HI, PR and VI) are non-continental areas that the file marks as not subject to the ceiling and floor, and they happen to list the same amount. The other 24 pay less.

The spread is small in money terms. Indiana, at $256.09, is the lowest, which puts the receiver's 20 percent at $51.22 instead of $60.25, a difference of $9.03 paid once. The rental and used rows follow the same state pattern. Because the monthly allowance is national, a move between states changes nothing about the recurring part of the bill.

Supplier or pharmacy: two counters, one Part B claim

CGMs reach Medicare patients through two kinds of businesses, and both bill the same benefit. Medicare's booklet on diabetes supplies (CMS Product No. 11022, July 2026) says Part B covers home glucose meters and related supplies, "and continuous glucose monitors and related supplies (like sensors)." On where to get them, it says you can order supplies from your pharmacy or through a medical equipment supplier after your doctor sends the prescription, and that with a mail-order pharmacy or supplier you will need to call to place your order.

For the price, the counter matters less than the agreement behind it. The booklet tells readers to use a pharmacy or supplier that participates in Medicare and accepts assignment, because those businesses agree to charge only the Medicare deductible and coinsurance, usually wait for Medicare to pay first, and must submit the claim themselves at no charge. If a pharmacy or supplier does not accept assignment, the booklet says, "you'll pay the entire charge at the time of service." The Medicare.gov CGM coverage page adds that for rented equipment, the supplier should accept assignment for all rental months, or you pay the full cost up front and Medicare pays you its share later.

So the codes, the fee schedule amounts and the 20 percent are the same at a pharmacy counter and from a mail-order supplier, as long as each accepts assignment and the claim goes to Part B. The questions to ask either one before the first order are the booklet's own: Do you participate in Medicare? Do you accept assignment? Medicare.gov's supplier directory, at medicare.gov/medical-equipment-suppliers, lists suppliers that participate.

The booklet places CGMs in the Part B section, apart from the Part D drug coverage it describes for insulin, oral diabetes drugs and some injection supplies. That placement explains why a CGM bill behaves like the CPAP rental under Part B, with a deductible and open-ended 20 percent, rather than like a drug-plan copay. The Part D out-of-pocket cap guide covers what does count toward the drug-plan threshold, and the discount card guide explains why a cash price paid outside the plan does not count toward a deductible.

Coverage criteria, read as claim requirements

Whether Medicare pays the A4239 line each month depends on documentation the DME MAC can check, and LCD L33822 spells it out. The LCD sets five initial criteria, all of which must be met, quoted here as billing conditions rather than as advice about who should use a CGM:

• The beneficiary has diabetes mellitus, with the diagnosis codes listed in the policy article.
• The treating practitioner has concluded that the beneficiary or caregiver has sufficient training using the CGM prescribed, as evidenced by providing a prescription.
• The CGM is prescribed in accordance with its FDA indications for use.
• The beneficiary is insulin-treated, or has a history of problematic hypoglycemia documented as either more than one level 2 event (glucose below 54 mg/dL) that persists despite more than one attempt to adjust medication or the treatment plan, or one level 3 event requiring third-party assistance.
• Within six months before the order, the treating practitioner had an in-person or Medicare-approved telehealth visit to evaluate diabetes control and determined that the first four criteria are met.

Continued coverage has one condition: every 6 months after the initial prescription, the treating practitioner conducts an in-person or Medicare-approved telehealth visit to document adherence to the CGM regimen and diabetes treatment plan. The LCD says that if any initial criterion or the continued-coverage criterion is not met, the CGM and the related supply allowance "will be denied as not reasonable and necessary." For the monthly bill, that visit is the date to watch: a gap in the six-month cycle is the most direct way for allowance claims to start denying.

Medicare.gov and the July 2026 booklet state the conditions in plainer words: the patient takes insulin or has a history of problems with low blood sugar, and the patient or caregiver has had enough training. The booklet adds that a CGM user must make routine in-person or Medicare-approved telehealth visits with the doctor. The practitioner visits are separate services with their own claims; they are not part of the A4239 allowance.

Three paperwork rules sit behind every claim. A Standard Written Order must reach the supplier before it submits a claim, or the claim is denied. Every device billed as E2103 must be on the Product Classification List kept by the Pricing, Data Analysis and Coding contractor (PDAC), or the claim is denied as incorrect coding. And when a supplier expects a reasonable-and-necessary denial, whether you owe the amount depends on a separate form; the Advance Beneficiary Notice guide explains what a valid ABN must contain and what happens without one.

Deliveries, 90-day claims and the strips you no longer buy

The allowance is billed monthly, but supplies do not have to arrive monthly. The policy article says a supplier does not have to deliver every month to bill A4238 or A4239 every month. It must, however, have already delivered enough supplies to last a full month, 30 days, after the date of service on each claim, and it must monitor usage. If what you have on hand will not last 30 days, more supplies must be delivered before the next month is billed.

Two caps bound the timing. Up to three months (90 days) of the allowance may be billed to the DME MAC at once, and suppliers may not dispense more than a 90-day supply. The LCD adds that billing more than 3 units per 90 days is denied as not reasonable and necessary. That is why a typical CGM statement shows a three-unit A4239 line every quarter rather than twelve single lines.

Refills need your request. The booklet says Medicare won't pay for any supplies you didn't ask for, or supplies sent to you automatically from suppliers. A shipment that arrived without a call or a request should not be on your claim, and the booklet lists 1-800-MEDICARE for automatic shipments and suspected supply fraud.

The meter and strips are where many people see a saving that does not show on any CGM statement. Under the LCD's usual-utilization rules for meters, an insulin-treated beneficiary can receive up to 300 test strips and 300 lancets every 3 months, billed as A4253 and A4259 with their own 20 percent. With a non-adjunctive CGM, A4239 already includes a meter and strips if needed, and separate meter and strip claims are denied. Adjunctive CGMs work differently: A4238 does not include a meter, and meter supplies may be billed in addition to it.

When competitive bidding reaches CGMs: one monthly rental

The two-line structure, a receiver plus a monthly allowance, has an end date in rule but not yet on the calendar. In the CY 2026 home health final rule, published December 2, 2025 and effective January 1, 2026, CMS finalized its proposal "to make payment under the DMEPOS CBP for certain continuous glucose monitors and insulin infusion pumps and all necessary supplies and accessories on a bundled monthly rental basis." It also finalized that CGMs furnished outside the bidding program will be paid on the same bundled monthly rental basis, limited to the amounts set under the program.

The rule also sets the timing trigger. All CGMs and insulin pumps paid under the fee schedule statute "will be classified as items requiring frequent and substantial servicing" beginning on the date class II CGMs and insulin pumps are first phased in under the bidding program, which the rule says CMS expects "will occur in the near future." Suppliers may bill up to 3 months of rental in advance. For class III CGMs, payment will be limited to the class II bid amounts if those are at least 15 percent lower than the class III fee schedule amounts.

The preamble shows how the first bid ceiling would be built, using 2025 amounts: the monthly A4239 fee of $267.92, plus the average purchase fee for an E2103 receiver, $286.03, divided by 60 months, or $4.77. That made a 2025 bid limit of $272.69 for a bundled nationwide monthly rental for class II non-adjunctive CGMs. Winning bids must come in below the limit, so the bundled rate would be lower, and your 20 percent would apply to that one monthly figure, with no separate receiver line.

Status as of 2026-10-31: the Competitive Bidding Implementation Contractor's site says the program has been in a temporary gap since January 1, 2024, until Round 2028 is implemented, and its Round 2028 page shows Phase 1, bid preparation, in progress since June 4, 2026, with registration, bidding, evaluation, contracting and the round itself not started and dated "TBD." Its Round 2028 timeline page gives target dates only: the bid window in late fall 2026, contracts announced in late summer or early fall 2027, and contracts in effect no later than January 1, 2028. The October 2026 fee file still pays A4239 monthly and E2103 as a purchase or rental, and the figures on this page reflect that file.

CMS has also flagged CGM codes for possible extra paperwork. A rule published January 13, 2026, effective April 13, 2026, added A4238, E2103 to the Master List of items potentially subject to face-to-face encounter, written order prior to delivery or prior authorization requirements, and a rule published July 30, 2026, effective October 28, 2026, added A4239 for aberrant billing patterns. The Master List is a list of items potentially subject to those requirements; neither rule added these codes to the required face-to-face or prior authorization lists.

Medicare Advantage, Medigap and help with the 20 percent

Everything above is Original Medicare arithmetic. A Medicare Advantage plan covers the same Part B benefit but can set its own DME cost sharing and supplier network. The numbers that decide your cost there are the plan's DME copayment or coinsurance and its network rules, both in the Evidence of Coverage.

Under Original Medicare, a Medigap policy's benefit summary shows how much of the Part B deductible and 20 percent it pays, which lowers the monthly figures above by that amount. People with limited income may qualify for a Medicare Savings Program that pays Part B cost sharing; the Medicare Savings Programs guide explains the programs and how to apply. For the wider set of fixed federal rules behind Medicare bills, see the Medicare and Medicaid costs hub, and for drug costs alongside the CGM, the prescription costs hub.

One quarter's CGM claim, line by line

A new Class III user who gets a receiver and a 90-day supply in January, with the deductible already met by other claims, would see something like this on a Medicare Summary Notice. The quantities are a stated example, and the amounts come from the October 2026 file.

The next three quarters would show only the three-unit A4239 KF line, $953.91 approved and $190.78 for you each time. Four points are worth checking on each notice: that the KF modifier matches the device, that the A4239 units do not exceed 3 per 90 days, that no separate sensor, transmitter, meter or strip lines appear for a non-adjunctive system, and that the approved amount matches the fee file for the quarter of the date of service. If a line was denied and you think it should not have been, the notice-reading guide walks through the fields, and the appeal guide covers the next steps.

CGM cost questions under Original Medicare

How much does a CGM cost per month with Original Medicare?

Once the Part B deductible is met and the supplier accepts assignment, you pay 20 percent of the monthly supply allowance. In the October 2026 DMEPOS fee schedule, A4239 is $273.28 a month, so your share is $54.66; for a device the FDA classifies as Class III, A4239 KF is $317.97, and your share is $63.59. These are Medicare anchors, not your bill.

Does Medicare pay for CGM sensors separately from the monthly allowance?

No. Policy Article A52464 says the supply allowance (A4238 or A4239) covers all items needed to use the device, including sensors and transmitters, and supplies billed separately are denied as unbundling. For a non-adjunctive CGM, A4239 also covers a home blood glucose meter and its strips, lancets, control solution and batteries, if needed.

What is the KF modifier on my CGM claim?

KF marks an FDA Class III device. The policy article requires KF on E2103 and A4239 when the device is Class III and forbids it when it is not. The modifier changes the fee: $317.97 instead of $273.28 a month for the supply allowance in October 2026, a difference of $44.69 allowed and $8.93 in your monthly 20 percent.

Will Medicare pay the CGM supply allowance if I only use my phone as the reader?

Not under the current policy article. It says the supply allowance is covered when a stand-alone durable receiver or an insulin pump classified as DME displays the data, and also when a phone or watch is used along with the durable receiver. If a beneficiary never uses a DME receiver or insulin pump to display the readings, the supply allowance is not covered. Smart devices themselves are billed as A9270, a non-covered item.

Can I get my CGM from a pharmacy instead of a medical supply company?

Yes. Medicare's diabetes supplies booklet (CMS Product No. 11022, July 2026) says you can order supplies from your pharmacy or from a medical equipment supplier, and it places CGMs under Part B. Either way, choose one that participates in Medicare and accepts assignment; if it does not accept assignment, the booklet says you pay the entire charge at the time of service.

Does CGM spending count toward the Part D out-of-pocket cap?

Medicare's booklet lists CGMs and their supplies under Part B, the medical equipment benefit, not under Part D drug coverage. The Part D cap tracks spending on covered Part D drugs. The Part D cap guide on this site explains what counts toward that threshold.

Is Medicare changing how it pays for CGMs?

Yes, but not yet. The CY 2026 home health final rule (effective January 1, 2026) finalized a bundled monthly rental payment for CGMs and all their supplies, starting on the date class II CGMs are first phased in under competitive bidding. As of October 31, 2026, the bidding contractor lists Round 2028 in Phase 1, bid preparation, with later phases carrying target dates only (contracts in effect no later than January 1, 2028), and the October 2026 fee schedule still pays A4239 monthly and E2103 as a purchase or rental.

The fee file, LCD and rules behind the CGM figures

• CMS, DMEPOS fee schedule DME26-D (October 2026 quarter), dme26-d.zip: DMEPOS_OCT.csv (A4239, A4238 and E2103 amounts in all 53 jurisdictions), Former CBA Fee Schedule File - OCT2026.csv (no CGM rows), DMEREAD 2026.pdf (KF definition, non-rural-only columns) and DMEBACK 2026.pdf (inexpensive item purchase cap, national ceiling and floor). Downloaded and checked 2026-10-31.
• DME MACs, LCD L33822, Glucose Monitors, version 70, revision effective October 1, 2024 (initial and continued coverage criteria, 3 units per 90 days, meter and strip denials with A4239, PDAC listing, written order). Checked October 31, 2026.
• DME MACs, Policy Article A52464, Glucose Monitor, version 65, effective February 18, 2025 (supply allowance contents, receiver and smart device rules, KF, KX, KS and CG modifiers, 30-day delivery rule, 90-day limit). Checked October 31, 2026.
• Federal Register, CY 2026 HH PPS final rule, 90 FR 55342 (December 2, 2025), FR Doc 2025-21767, effective January 1, 2026 (bundled monthly rental for CGMs, frequent and substantial servicing class, 15 percent class III limit, 2025 bid-limit example). Checked October 31, 2026.
• Competitive Bidding Implementation Contractor, Round 2028 program phases (Phase 1 in progress since June 4, 2026; later phases TBD). Checked 2026-10-31.
• Competitive Bidding Implementation Contractor, Round 2028 timeline (target dates; updated June 4, 2026). Checked October 31, 2026.
• Federal Register, Master List updates: 91 FR 1250 (January 13, 2026), FR Doc 2026-00487 (effective April 13, 2026) and 91 FR 47972 (July 30, 2026), FR Doc 2026-15446 (effective October 28, 2026). Checked October 31, 2026.
• Medicare.gov, Continuous glucose monitors (Part B, eligibility summary, assignment) and Medicare Coverage of Diabetes Supplies, CMS Product No. 11022, July 2026 (pharmacy or supplier, assignment, no automatic shipments, strip limits). Checked October 31, 2026. 2026 Part B deductible of $283.00 from Medicare costs, checked October 30, 2026.
• eCFR, 42 CFR 414.210 (80 percent of the lesser of the actual charge or the fee schedule amount; replacement of equipment). Checked October 30, 2026.

General billing information, not medical, legal or insurance advice. DMEPOS fee schedule amounts are Medicare anchors, not your bill, and a supplier or pharmacy that does not accept assignment, a Medicare Advantage plan or a supplement can change what you pay. Confirm your price in writing before service.