Podiatry Coding & Billing Alert

Anesthesia services are reimbursed differently from other procedure codes. Part of the payment for anesthesia is based on “base units,” which are assigned to anesthesia CPT^® codes by the Centers for Medicare & Medicaid Services (CMS). The remainder of the payment allowance is based on the time the patient was under anesthesia.

Keying in time will depend on your software. You should enter the anesthesia time exactly as documented — software systems usually have parameters in place that determine whether to round time up or down and how to report to each payer. However, not all anesthesia software is sophisticated enough to follow the many payer requirements. When coders enter anesthesia time for charges, the system is typically set to round time up to the nearest whole unit.

Do this: The best way to report is to provide exact minutes for total time and include anesthesia start and stop times on the claim.

Correctly coding and reporting charges involves the following criteria:

• The difficulty of the procedure performed (base units)
• Time (time units)
• Modifying factors (modifying units)

The general formula for calculating anesthesia charges is:

(Base units + Time units + Modifying units) x Anesthesia conversion factor = Anesthesia charge

“For 2024 CMS has the anesthesia conversion factor set at 20.4349. It is important to note it will be different across payers,” says Jennifer McNamara, CPC, CCS, CRC, CPMA, CDEO, COSC, CGSC, COPC, director of healthcare training and practice support at Healthcare Inspired LLC, in Bella Vista, Arkansas.

Note: Modifying units includes consideration of emergencies and the patient’s changing health conditions.

Also, you should not report base units separately on the claim. Base units are determined by the difficulty of the anesthesia procedure and calculated by payers, typically using either the CMS or the American Society of Anesthesiologists (ASA) base values.