CPT code 93898: Shunt detection, IV microbubble injection2026 Medicare rate & RVUs

Medicare pays $262.53 for 93898 nationally in the office. Local office rates run $228.50–$366.94.

Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.

What 93898 covers

This service uses transcranial Doppler monitoring to look for microbubbles passing from the venous circulation into the cerebral arteries, indicating a right-to-left shunt. It may be part of an evaluation for a suspected shunt, including in a patient with an otherwise unexplained stroke or suspected paradoxical embolism. A vascular or neurovascular ultrasound team performs the monitoring, and a qualified clinician interprets the findings.

Report 93898 only as an add-on with 93893; it is not a standalone service. Documentation should support the shunt evaluation and record the intravenous microbubble administration, Doppler monitoring, and interpretation. CMS identifies separately priced professional and technical components: modifier 26 represents the interpretation, modifier TC represents the equipment and staff, and billing without either modifier represents the global service. Payment for this add-on is within the primary procedure’s global period.

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 93898 pays more and less

The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.

109 of 109 payment localities

93898 rates by state

Office rate range in each state. Select a state to see its payment localities.

How the 93898 rate is calculated

Each of 93898’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.

Payment rules and modifiers for 93898

The CMS indicators that decide how 93898 is paid alongside other services.

What modifiers do to the payment

When to use modifier 26

93898 compared with similar codes

How to choose

93893Transcranial DopplerVenous-arterial shunt detection

93893 is the primary procedure for the transcranial Doppler shunt study; 93898 is reported with it for shunt detection using intravenous microbubble injection.

93892Emboli detectionWithout injection

93892 concerns emboli detection without intravenous microbubble injection. Use 93898 with its primary procedure when the service is venous-to-arterial shunt detection.

93886Intracranial DopplerComplete study

93886 represents a complete intracranial Doppler study, not the microbubble shunt-detection add-on reported with 93893.

93888Transcranial DopplerLimited intracranial study

93888 represents a limited intracranial Doppler study; 93898 is for microbubble shunt detection and requires its primary procedure.

Codes related to 93898

Related codes aren’t interchangeable: bill the code that matches the service performed.

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

Open CMS sourceHow we calculate rates