Plethysmography — NCD 165 | CMS Coverage Update

TL;DR: The Centers for Medicare & Medicaid Services modified NCD 165 governing plethysmography coverage, with an effective date of March 7, 2026. Here's what billing teams need to know before submitting claims.

CMS plethysmography coverage policy under NCD 165 draws a hard line between covered diagnostic procedures and experimental ones. This update clarifies which plethysmographic methods qualify for Medicare reimbursement — and which will trigger a claim denial. This policy does not list specific CPT or HCPCS codes in the policy document itself, so your billing team needs to map the covered and excluded procedure types to the correct codes using your charge master and CMS coding resources.

Quick-Reference Table

CMS Plethysmography Coverage Criteria and Medical Necessity Requirements 2026

NCD 165 in the CMS Medicare system defines plethysmography as the measurement and recording of changes in the size of a body part as modified by blood circulation. The coverage policy splits procedures into two categories: covered (Category I) and experimental (Category II). Medical necessity is the deciding factor for whether a claim gets paid or denied.

To meet medical necessity under this coverage policy, the procedure must be used for one of three accepted clinical purposes. First, noninvasive diagnostic, preoperative, or postoperative evaluation of peripheral artery disease — in an internal medicine or vascular surgery setting. Second, preoperative podiatric evaluation of a diabetic patient. Third, evaluation of a patient with intermittent claudication or other signs of peripheral vascular disease that affects candidacy for foot surgery.

CMS is explicit: denial authority for claims that lack medical necessity or use a noncovered method falls under §1862(a)(1) of the Social Security Act. That's the statutory hook your MAC will use when they reject the claim. Document the clinical indication clearly in the medical record before the procedure goes on the schedule.

This policy does not mention prior authorization requirements at the NCD level. However, your Medicare Administrative Contractor may have a Local Coverage Determination that layers additional prior authorization or documentation requirements on top of the NCD. Check with your MAC before assuming NCD 165 alone clears the claim.

Plethysmography billing under Medicare requires that the method used is a Category I procedure. The setting also matters. Venous occlusive pneumoplethysmography, the oldest method, is specifically called out as appropriate in a hospital vascular laboratory setting — but CMS explicitly says it is "unsuitable for routine use in the physician's office." Bill that one from an office setting and you're building toward a denial.

CMS Plethysmography Exclusions and Non-Covered Indications

Four specific plethysmographic methods are classified as experimental under NCD 165. CMS considers them not covered at this time. Billing any of these methods to Medicare is a claim denial waiting to happen — and depending on volume, potentially a compliance exposure.

Inductance Plethysmography is classified experimental because it does not produce reproducible results. Capacitance Plethysmography carries the same designation for the same reason. These aren't borderline calls. CMS is clear.

Mechanical Oscillometry is non-standardized, offers poor sensitivity, and CMS has determined it is not superior to simply measuring peripheral blood pressure. That's the standard it failed to meet. Photoelectric Plethysmography is the most limited of the four — CMS says it is useful only for determining whether a pulse is present. That's not a diagnostic procedure for peripheral vascular disease; it's a basic check. Not covered.

If your practice or facility has been using any of these methods and billing them to Medicare, stop and audit. Talk to your compliance officer before submitting any more claims that include these procedures. The financial and compliance exposure here is real.

Coverage Indications at a Glance

CMS Plethysmography Billing Guidelines and Action Items 2026

This policy change is effective March 7, 2026. These are your action items before that date.

CPT, HCPCS, and ICD-10 Codes for Plethysmography Under NCD 165

A Note on Code Availability

NCD 165 does not list specific CPT or HCPCS codes within the policy document itself. This is not unusual for older NCDs — many predate the current CPT code structure. Your billing team needs to identify the correct codes using the CMS Medicare Coverage Database, your MAC's LCD (if one exists), and your charge master.

The policy identifies covered methods by name. Work with your coding team or a billing consultant to confirm the current CPT codes that correspond to each Category I method before the effective date of March 7, 2026.

Category I — Covered Methods (No Specific CPT Listed in Policy)

Category II — Experimental / Not Covered Methods

No ICD-10-CM codes are specified in the NCD 165 policy document. Your coding team should assign diagnosis codes based on the clinical indications documented — peripheral artery disease, peripheral vascular disease, diabetic preoperative evaluation — using standard ICD-10-CM coding conventions and any guidance in your MAC's LCD.