Key facts for NCD 20.17
- Benefit category
- Diagnostic Tests (other)
- Effective date
- 11/15/1980
- Transmittal
- n/a
- Versions published
- 1
- Manual chapter
- 20
- NCD Manual (Pub. 100-03)
TL;DR
NCD 20.17 sets Medicare's national policy for noninvasive tests of carotid function under the benefit category "Diagnostic Tests (other)", effective 11/15/1980. It is important to note that the names of these tests are not standardized. Following are some of the acceptable tests, recognizing that this list is not inclusive and that local medical consultants should make determinations: It has been revised once since publication and binds every Medicare Administrative Contractor nationally.
Item or service described
Noninvasive tests of carotid function aid physicians in studying and diagnosing carotid disease. There are varieties of these tests which measure various anatomical and physiological aspects of carotid function, including pressure (systolic, diastolic, and pulse), flow, collateral circulation, and turbulence.
For operational purposes, it is useful to classify noninvasive tests of carotid function into direct and indirect tests. The direct tests examine the anatomy and physiology of the carotid artery, while the indirect tests examine hemodynamic changes in the distal beds of the carotid artery (the orbital and cerebral circulations).
Indications and limitations of coverage
It is important to note that the names of these tests are not standardized. Following are some of the acceptable tests, recognizing that this list is not inclusive and that local medical consultants should make determinations:
Direct Tests
• Carotid Phonoangiography
• Direct Bruit Analysis
• Spectral Bruit Analysis
• Doppler Flow Velocity
• Ultrasound Imaging including Real Time
• B-Scan and Doppler Devices
Indirect Tests
• Periorbital Directional Doppler Ultrasonography
• Oculoplethysmography
• Ophthalmodynamometry
Text reproduced from the CMS Medicare Coverage Database record for NCD 20.17 version 1. View the original on cms.gov.
How this NCD shows up on remittances
A service denied under a National Coverage Determination returns CARC 50 (not deemed medically necessary) with remark N386 (decision based on an NCD); a denial citing a local policy instead carries N115. Because NCDs bind nationally, the appeal path is documentation that the patient meets the indications above, not a contractor-policy argument.
How QuickIntell applies NCD 20.17
QuickAuth checks the ordered service and diagnosis against NCD and LCD criteria before the encounter, QuickCode validates the diagnosis pairing on the claim, and QuickRCM routes CARC 50 denials with the policy text and the covered-code list attached so the appeal starts with evidence.
Frequently asked questions — NCD 20.17
What does NCD 20.17 cover?
It is important to note that the names of these tests are not standardized. Following are some of the acceptable tests, recognizing that this list is not inclusive and that local medical consultants should make determinations: The full indications and limitations are reproduced on this page from the CMS Medicare Coverage Database.
When did NCD 20.17 take effect?
The current version (1) is effective 11/15/1980. This is the only published version.
Does a Local Coverage Determination override NCD 20.17?
No. A National Coverage Determination binds all Medicare Administrative Contractors; an LCD can only address services or circumstances the NCD leaves open. Claims denied under this NCD typically return CARC 50 with remark N386 (NCD) rather than N115 (LCD).
Sources
Every figure on this page is taken from the CMS publications below, as released by the Centers for Medicare & Medicaid Services. Projection built 2026-10-02. Verify against the primary file before billing or contracting decisions.
- Medicare Coverage Database NCDs via the CMS Coverage APIVersion API snapshot 2026-09-27 · effective 2026-09-20 · file national-coverage-ncd.jsonSHA-256 a90fadfd264b9ef4…
Disclaimer
This page reproduces the CMS National Coverage Determination text and, for laboratory NCDs, the CMS ICD-10 edit lists, as an operational reference. Coverage decisions depend on the full policy, the claim and the contractor; nothing here is legal, clinical or billing advice. CPT codes are shown as numbers only; CPT descriptors are copyright AMA.