There is no single ICD-10 code that universally covers a DEXA scan for Medicare. Instead, Medicare requires a qualifying diagnosis code that establishes medical necessity, and the right code depends on why the scan is being ordered. The most commonly used codes fall under the M81 family for osteoporosis without fracture, the M80 family for osteoporosis with a current pathological fracture, and several risk-factor codes like E21.0 for primary hyperparathyroidism or Z79.52 for long-term steroid use. Getting the diagnosis code right matters because a mismatch between the code submitted and Medicare’s coverage criteria is one of the most common reasons claims get denied.
How Medicare Decides Whether to Cover a DEXA Scan
Medicare’s coverage of bone density testing goes back to the Bone Mass Measurement Act of 1997, which established five categories of people who qualify. The scan itself is billed using CPT procedure codes (77080 for axial DEXA, 77081 for appendicular, and related codes), but it is the ICD-10 diagnosis code that tells Medicare why the patient needs the test. If the diagnosis code does not match one of Medicare’s approved indications, the claim is rejected regardless of how clinically reasonable the scan might be.
Medicare Part B covers DEXA scans for beneficiaries who fall into at least one of these qualifying groups:
- Estrogen-deficient women: Those at clinical risk for osteoporosis, as determined by the referring physician based on medical history and other risk factors.
- Vertebral abnormalities: Individuals whose X-rays show vertebral fractures or significant bone loss in the spine.
- Glucocorticoid therapy: Individuals currently receiving or expected to receive long-term glucocorticoid (steroid) therapy equivalent to 5 mg or more of prednisone per day for three months or longer.
- Primary hyperparathyroidism: Individuals diagnosed with this endocrine condition, which accelerates bone loss.
- Monitoring osteoporosis treatment: Individuals already on an FDA-approved osteoporosis medication whose physician needs to assess whether the treatment is working.
Each of these categories maps to a different set of ICD-10 codes. Getting the right one on the order is the billing step where things most often go wrong.
The ICD-10 Codes Used Most Often
The specific code your provider submits depends on your clinical situation. Here are the groupings that come up most frequently in Medicare DEXA claims:
For patients with known or suspected osteoporosis, the M81 codes are the workhorses. M81.0 covers age-related osteoporosis without a current pathological fracture, and it is probably the single most commonly billed diagnosis code for DEXA scans in the Medicare population. If you have already been diagnosed with osteoporosis and are getting a follow-up scan, this is usually the code. The M80 family covers osteoporosis with a current pathological fracture and is site-specific, so there are separate codes depending on whether the fracture is in the shoulder region (M80.01), the humerus (M80.02), the forearm (M80.03), and so on.
For patients with risk factors but no established osteoporosis diagnosis, several other codes come into play:
- Z79.52: Long-term use of systemic steroids. This directly corresponds to Medicare’s glucocorticoid category.
- E21.0: Primary hyperparathyroidism. This maps to its own qualifying category.
- E28.310: Premature menopause, or other codes indicating estrogen deficiency. Surgical menopause after oophorectomy also qualifies and would use a different E-code or Z-code depending on the documentation.
- M48.50 and related: Collapsed vertebra or vertebral compression fracture. These support coverage under the vertebral-abnormality category.
- Z87.310: Personal history of healed osteoporosis fracture. Useful for follow-up scans when the acute fracture has resolved but bone density monitoring is still needed.
A code like Z13.820, which is specifically for osteoporosis screening encounters, looks like it should be the obvious choice for a first-time DEXA. In practice, some Medicare Administrative Contractors accept it and others do not treat it as sufficient to establish medical necessity on its own. Providers often pair it with or substitute a more specific risk-factor code to avoid denial.
Frequency Limits and When the Clock Resets
Medicare generally covers one DEXA scan every 24 months, counting from the date of the previous scan. This frequency limit applies even when the diagnosis code is perfectly appropriate. If you had a DEXA in January 2024, Medicare typically will not pay for another one until January 2026.
There are exceptions. Medicare allows more frequent testing if your doctor documents a medical reason the standard 24-month interval is not sufficient. The most common situations where a shorter interval gets approved include starting or changing an osteoporosis medication, beginning a new course of glucocorticoid therapy that is expected to cause bone loss, or discovering a new condition that accelerates bone turnover. In these cases, the provider must document the clinical justification clearly, and the ICD-10 code on the claim needs to reflect the changed medical circumstances, not just repeat the code from the previous scan.
A frequent mistake is ordering a repeat DEXA at, say, 18 months because the physician wants to check progress. Medicare will deny that claim unless there is documentation explaining why 24 months was too long to wait. The denial is not about the diagnosis code itself being wrong but about the timing not meeting coverage rules.
Why Claims Get Denied and How to Avoid It
Most DEXA claim denials for Medicare patients come down to a few recurring issues. The first is a mismatch between the diagnosis code and Medicare’s qualifying categories. If a provider submits a code for general bone pain (M89.9, for instance) without also coding one of the five qualifying conditions, Medicare’s system flags it as lacking medical necessity. Bone pain on its own is not one of the approved indications, even if the clinical reason for ordering the scan is completely sound.
The second common problem is submitting an unspecified osteoporosis code when a more specific one is available. ICD-10 was designed to be granular, and Medicare’s systems increasingly expect the most specific code the documentation supports. Using M81.0 (age-related osteoporosis) when the chart shows the patient has drug-induced osteoporosis (M81.4) or osteoporosis related to malabsorption (M81.8) can trigger a review or denial, depending on the Medicare Administrative Contractor handling the claim.
The third issue is ordering the scan before the 24-month interval has passed without adequate documentation of medical necessity for the shorter interval. Even the right ICD-10 code will not save a claim that fails the timing rule.
If you are the patient and your claim is denied, you have the right to appeal. The first step is usually asking your provider’s office to review the submitted codes and make sure the diagnosis code accurately reflects your medical record. A surprising number of denials are resolved simply by correcting a coding error on resubmission. If the code was correct and the denial was for medical necessity, your provider can submit a redetermination request with supporting clinical documentation.
The Difference Between Diagnosis Codes and Procedure Codes
A point of confusion for many patients, and even some billing staff, is the difference between the ICD-10 code and the CPT code on a DEXA claim. The ICD-10 code answers the question “why does this patient need this test?” The CPT code answers the question “what test was actually performed?” Both appear on the same claim, and both must be correct for Medicare to pay.
For DEXA scans specifically, the relevant CPT codes are 77080 for a dual-energy X-ray absorptiometry scan of the axial skeleton (spine, hip, or both), 77081 for a scan of the appendicular skeleton (wrist, heel, or other peripheral site), and 77085 or 77086 for vertebral fracture assessment, which some providers perform alongside the standard bone density measurement. Medicare covers 77080, the axial scan, as the standard bone density test. Peripheral scans billed under 77081 are covered in some contexts but are not considered equivalent to a central DEXA for osteoporosis diagnosis.
The ICD-10 code and the CPT code need to tell a consistent story. If the procedure code says the patient received an axial DEXA (77080) but the diagnosis code is for a peripheral bone disorder unrelated to one of Medicare’s five qualifying categories, the claim creates a logic problem for the payer’s system. Billing offices typically maintain crosswalk tables that match approved ICD-10 codes to each CPT procedure code for exactly this reason.
Men and DEXA Scan Coverage
One of Medicare’s five qualifying categories specifically mentions estrogen-deficient women, which leads to a persistent misconception that Medicare does not cover DEXA scans for men. Medicare does cover bone density testing for men, but the qualifying pathway is different. Men typically qualify under the glucocorticoid, hyperparathyroidism, vertebral abnormality, or treatment-monitoring categories rather than the estrogen-deficiency category. Men with hypogonadism (low testosterone), which is a significant risk factor for osteoporosis, can also qualify when their physician documents the clinical indication and uses an appropriate ICD-10 code such as E29.1 for testicular hypofunction.
Despite this coverage, bone density testing in men remains strikingly underused. A study of more than 10,000 men with a hypogonadism diagnosis in their medical records found that only about 7% underwent bone density testing. Among those who were tested, nearly half had osteopenia and about 12% had full osteoporosis, suggesting that the men who were not tested likely included many with undiagnosed bone loss.1PubMed Central. Lack of Bone Mineral Density Testing in Men With Hypogonadism: A Clinical Conundrum The issue is not that Medicare refuses to cover the scan for men. It is that the scan is not being ordered in the first place, often because both patients and providers associate osteoporosis and DEXA scans primarily with postmenopausal women.
If you are a man on long-term steroid therapy, have been diagnosed with hypogonadism, or have other risk factors for bone loss, ask your provider about a DEXA scan. The coverage pathway exists; it just requires the right diagnosis code to match your clinical situation.
Medicare Advantage and Supplemental Plans
Everything described so far applies to Original Medicare (Part B). If you have a Medicare Advantage plan (Part C), coverage for DEXA scans must be at least as broad as Original Medicare, because Advantage plans are required to cover everything Original Medicare covers. However, the prior authorization requirements can differ. Some Medicare Advantage plans require the ordering provider to get advance approval before the scan, while Original Medicare does not. If your Advantage plan denies a DEXA scan that would be covered under Original Medicare, that is grounds for an appeal.
Medigap (Medicare Supplement) plans do not change the coverage rules for DEXA scans. They cover cost-sharing, meaning they pay the coinsurance and deductible amounts that Original Medicare leaves to you. Under Original Medicare with no supplement, you typically owe 20% of the Medicare-approved amount for a DEXA scan after meeting your Part B deductible. A Medigap plan may pick up some or all of that 20%, depending on which lettered plan you have.
When Your Doctor Thinks You Need a Scan but Medicare May Not Agree
There are clinical situations where a DEXA scan makes medical sense but does not fit neatly into Medicare’s five qualifying categories. A common example is a patient with a strong family history of osteoporosis and multiple minor risk factors (low body weight, smoking history, heavy alcohol use) who does not yet have a specific qualifying diagnosis like hyperparathyroidism or documented estrogen deficiency. In these cases, the ordering physician may need to identify which qualifying category best fits and document accordingly, or the patient may face a coverage gap.
Another gray area involves patients who have had a fragility fracture but whose medical record does not yet contain a formal osteoporosis diagnosis. A fragility fracture itself is a strong indicator of underlying osteoporosis, and the DEXA scan is being ordered to confirm and quantify it. The ICD-10 code for the fracture (an M80 code if it is clearly pathological, or a traumatic fracture code with additional context) needs to tell Medicare that the scan is being ordered to evaluate a suspected bone density problem, not just to follow up on the fracture itself.
Providers sometimes use an Advance Beneficiary Notice (ABN) in borderline situations. An ABN is a form that tells you, before the test is performed, that Medicare may not pay for it and that you may be responsible for the cost. Signing an ABN does not mean the scan will definitely be denied. It means the provider is not confident the claim will go through and wants you to understand the financial risk before proceeding. If you are asked to sign one, it is worth having a conversation with your provider about whether a different ICD-10 code might better reflect your situation and improve the chance of coverage.
Screening Versus Diagnostic Scans
Medicare draws a line between screening tests and diagnostic tests, and this distinction affects DEXA coverage in a way that confuses many beneficiaries. A screening DEXA is one ordered for someone with no symptoms and no prior diagnosis, purely to check whether bone loss is present. A diagnostic DEXA is ordered because the patient already has symptoms, risk factors, or a known condition that makes bone loss likely.
The Bone Mass Measurement Act technically covers both screening and diagnostic scans for people who meet the five qualifying categories. But in practice, the ICD-10 code determines which side of the line the claim falls on. A code like Z13.820 (encounter for screening for osteoporosis) signals a screening scan, while a code like M81.0 (age-related osteoporosis) or E21.0 (hyperparathyroidism) signals a diagnostic scan with a clear medical rationale. Claims coded as screening sometimes face more scrutiny, and many billing professionals recommend using the most specific diagnosis code the patient’s chart supports rather than defaulting to a screening code.
This does not mean screening is not covered. It means the coding strategy matters. If you are a 66-year-old woman with no prior fractures, no steroid use, and no endocrine disorder, but you are postmenopausal and your doctor wants a baseline DEXA, the estrogen-deficiency qualifying category applies. The ICD-10 code should reflect the estrogen deficiency or menopausal status, not just “screening.” The clinical reality is the same either way, but the way it is coded determines whether Medicare pays without a fight.