CPT code 78650: CSF leak imaging, leak detection and localization2026 Medicare rate & RVUs

Medicare pays $245.16 for 78650 nationally in the office. Local office rates run $212.57–$344.86.

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

What 78650 covers

This nuclear medicine study traces cerebrospinal fluid to identify and localize a suspected leak. It may be used when a patient has signs of CSF leakage, including persistent clear drainage after head or spinal surgery or trauma. A radiologist or nuclear medicine physician interprets the resulting images; the technical service involves the imaging equipment and staff. The study is generally performed in a hospital or imaging department equipped for nuclear medicine procedures.

Select 78650 when the diagnostic purpose is finding and locating a CSF leak, rather than evaluating general CSF circulation, ventricular anatomy, or shunt function. Documentation should identify the suspected leak, the imaging procedure performed, and the physician’s interpretation and findings. Medicare recognizes professional and technical components: report modifier 26 for interpretation, modifier TC for equipment and staff, or no modifier for the global service when one entity provides both.

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 78650 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

78650 rates by state

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

How the 78650 rate is calculated

Each of 78650’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 78650

The CMS indicators that decide how 78650 is paid alongside other services.

What modifiers do to the payment

When to use modifier 26

78650 compared with similar codes

How to choose

78630CSF scanCisternography

Choose 78650 when the study is specifically intended to find and localize a CSF leak. Choose 78630 for a cisternographic CSF study.

78645CSF shunt studyShunt patency assessment

78645 evaluates a CSF shunt; 78650 investigates suspected leakage from the CSF space.

78635CSF imagingVentricular flow study

78635 is radiopharmaceutical ventriculography focused on the ventricular system. 78650 is directed at detecting and localizing CSF leakage.

Codes related to 78650

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