Bone mineral density measurement of the axial skeleton (usually the spine or hips) using quantitative computed tomography rather than DXA.
- Medicare
- $98.87
- Work RVU
- 0.24
- Global, days
- Region
- Spine
Documentation requirements
What must appear in the operative or office note to support the claim.
Source · Editorial brief grounded in 3 cited references ↓
- Indication meeting bone mass measurement coverage, such as estrogen deficiency, vertebral abnormality, glucocorticoid therapy, or hyperparathyroidism
- Reason QCT was chosen over DXA when applicable
- Date of last bone density study of any type
- Sites measured and density values
- Signed interpretation with risk assessment
Applicable modifiers
Modifiers commonly billed with this code.
Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual
What this code covers
Source · Editorial summary grounded in 3 cited references ↓
Quantitative CT (QCT) measures true volumetric bone density, typically in the lumbar spine. Most practices use DXA (77080) instead because it is cheaper and lower dose, but QCT is useful when DXA numbers are unreliable: heavy lumbar degenerative change, prior spine fusion hardware, or significant aortic calcification that inflates spine DXA readings.
For Medicare, 77078 is a bone mass measurement, so the same frequency rules as DXA apply. For Medicare that means no more than once every 23 months unless the patient meets an exception, such as monitoring glucocorticoid therapy. A DXA and a QCT inside the same window will usually deny the second one.
For spine surgeons, QCT can help in planning fixation for osteoporotic bone. If it is done from an existing CT dataset rather than a separate scan, check payer rules, because some will not pay for density analysis from a scan billed for another purpose.
RVU & reimbursement
Component RVUs and Medicare national rate. Actual payment varies by GPCI locality.
Source · CMS Physician Fee Schedule, RVU26A · January 2026
Work RVU vs. total RVU
The work RVU (0.24) is the surgeon's own effort — the figure physician pay and productivity targets are built on. The total RVU (2.96) adds practice overhead and malpractice, and is what drives the Medicare payment below.
| Work RVU | 0.24 |
| Practice expense RVU | 2.7 |
| Malpractice RVU | 0.02 |
| Total RVU | 2.96 |
| Medicare national rate | $98.87 |
| Global period | days |
Payment by site of service
Medicare pays different rates by setting. HOPD typically pays substantially more than ASC for the same procedure.
Source · CMS OPPS Addendum B·ASC HCPCS payment rates·2026
| Setting | Medicare rate (national) |
|---|---|
Office (PFS non-facility) Procedure performed in physician's office | $98.87 |
HOPD (APC 5521) Hospital outpatient department | $88.91 |
Common denial reasons
The recurring reasons claims for CPT 77078 get rejected.
Source · Editorial brief grounded in CMS NCCI edits, AAOS coding appeals, and cited references ↓
- Repeat bone density within the Medicare frequency window without a covered exception
- DXA and QCT billed within the same frequency period
- Diagnosis does not meet bone mass measurement coverage criteria
- Density analysis billed from a CT done for another purpose without payer support
- Missing interpretation
Frequently asked questions
Source · Generated from the editorial pipeline, verified against 3 cited references ↓
01Does Medicare cover QCT bone density 77078?
02Can you bill 77078 and 77080 in the same year?
03Why choose QCT over DXA?
Sources & references
Editorial content was developed using the following public sources.
- 01CMS Physician Fee Schedule 2026
- 02Medicare NCD 150.3 Bone (Mineral) Density Studies
- 03cms.govhttps://www.cms.gov/medicare-coverage-database/search.aspx
Mira Scribe
Mira Scribe notes the qualifying risk factor and the date of the patient's last density study in the visit, which are the two facts frequency edits check.
See how Mira captures CPT 77078 documentation