CPT code 94450: Hypoxia response test2026 Medicare rate & RVUs in Illinois
Reports testing of a patient's breathing response during controlled hypoxia, typically in a pulmonary function laboratory when ventilatory response is being evaluated.
Medicare pays $105.68–$117.36 for 94450 in the office in Illinois, from Rest Of Illinois to Suburban Chicago. Which amount applies depends on the service address.
Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.
On this page 9 sections
What 94450 covers
This pulmonary function study evaluates how a patient's breathing responds when the inspired oxygen level is reduced under controlled testing conditions. It may be performed in a pulmonary function laboratory or outpatient facility, with pulmonary staff conducting the test and a physician or qualified health care professional interpreting the findings. The clinical question is the ventilatory response to hypoxia, rather than oxygen saturation during exertion or oxygen needs at simulated altitude.
Report 94450 when the documented service is a controlled assessment of breathing response to hypoxia. The record should support the test performed, the measurements obtained, and the interpretation. CMS recognizes separately priced professional and technical components: modifier 26 identifies the interpretation, modifier TC identifies the equipment and staff portion, and reporting without either modifier represents the global service. The professional and technical portions may be billed separately when furnished by different entities.
This summary was written with AI assistance from CMS physician fee schedule data and checked against the CMS billing rules shown here. Rates on this page come directly from CMS files.
Where 94450 pays more and less in Illinois
The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.
4 payment localities
$105.68 to $117.36
| Payment locality | Office | Facility |
|---|---|---|
| Chicago | $115.88 | Unavailable |
| East St. Louis | $106.98 | Unavailable |
| Rest Of Illinois | $105.68 | Unavailable |
| Suburban Chicago | $117.36 | Unavailable |
How the 94450 rate is calculated
Each of 94450’s three RVUs is multiplied by a geographic index (GPCI) for the payment locality, added up, and multiplied by the conversion factor. Drag the indexes or enter a ZIP to see what moves the rate.
How the rate is built · 94450
RVUs × geographic indexes × conversion factor
Work0.39
0.39 RVUs× 1.000 GPCI
Practice expense2.97
2.97 RVUs× 1.000 GPCI
Malpractice0.04
0.04 RVUs× 1.000 GPCI
Adjusted RVUs
3.4000
Conversion factor
$33.4009
Medicare rate
$113.56
Every GPCI starts at 1.000, the national rate. Enter a ZIP or drag a slider.
Payment rules and modifiers for 94450
The CMS indicators that decide how 94450 is paid alongside other services.
CMS payment indicators · 94450
Hypoxia response test
| Rule | CMS value | What it means |
|---|---|---|
| Global period | XXX | The global surgery concept doesn’t apply. |
| Multiple procedures | 0 | No multiple-procedure reduction. |
| Bilateral (modifier 50) | 0 | The 150% bilateral adjustment doesn’t apply. |
| Assistant at surgery (80/81/82/AS) | 0 | Not paid without supporting documentation. |
| Co-surgeons (62) | 0 | Not permitted. |
| Team surgery (66) | 0 | Not permitted. |
| Professional/technical | 1 | Diagnostic test with separate professional (26) and technical (TC) components. |
What modifiers do to the payment
Modifier 26 · payment effect
With and without the modifier
94450 without 26 · national office
$113.56
Hypoxia response test
94450-26 · Professional component
$22.71
Pays only the interpretation and report.
94450 compared with similar codes
Compare codes · National
4 codes, side by side
How to choose
- 94452Altitude simulation test
- Choose 94450 for a controlled test of breathing response to hypoxia. Choose 94452 when the study simulates altitude to evaluate oxygenation.
- 94453Altitude simulation
- 94453 adds supplemental oxygen titration during high altitude simulation testing; 94450 evaluates ventilatory response to hypoxia.
- 94618Pulmonary stress test
- 94618 evaluates physiologic response during pulmonary stress testing, such as a walk test. It does not represent controlled hypoxia testing.
94450 billing questions
How does 94450 differ from a high altitude simulation test?
94450 evaluates the breathing response to controlled hypoxia. High altitude simulation testing evaluates oxygenation under simulated altitude conditions, with or without supplemental oxygen titration.
Does 94450 include both testing and interpretation?
Reporting without a component modifier represents the global service. Modifier 26 identifies the professional interpretation, while modifier TC identifies the technical service, including equipment and staff.
What documentation supports reporting 94450?
Document the controlled hypoxia test performed, the measurements used to assess breathing response, and the interpreting clinician's findings.
When should modifier 26 or TC be used?
Use modifier 26 for the interpretation and modifier TC for the equipment and staff portion when billing those components separately. Report the service without either modifier when billing the global service.
Can exercise testing be reported instead of 94450?
A pulmonary stress test such as 94618 addresses physiologic response to exercise, including oxygen saturation monitoring. It is not a substitute when the documented service is a controlled assessment of breathing response to hypoxia.
Where these rates come from
FeeBase calculates base physician payments from CMS work, practice-expense and malpractice RVUs, adjusted by each locality’s geographic indexes and the conversion factor. Services without a published rate are labeled, never given a made-up amount. Amounts are Medicare allowed amounts before claim adjustments: not a patient’s bill or a commercial rate.
CMS RVU26D · effective Oct 1, 2026 through the day before Jan 1, 2027
Show the CMS file lines behind this rate
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