Anesthesia Billing

Anesthesia billing and CRNA pass-through can be complicated. We have outlined information below related to billing for Anesthesia services or CRNA pass through as a tip sheet for providers to review and reference when questions arise in this area.

The following information applies if the facility is billing Medicare with a 964 revenue code for a Method II anesthesia service (outpatient services only) or CRNA pass through (outpatient and inpatient services) for Medicare and Medicaid (471 10-010.03B13). All other payers are billed on a 1500 claim form.


P Modifiers

The use of the P modifiers requires the anesthesia professional to document the underlying systemic disease condition(s) on the pre-anesthesia evaluation. The systemic disease conditions documented on the pre-anesthesia evaluation must be substantiated by provider documentation in the preoperative notes or history and physical.

These underlying systemic disease condition diagnosis codes should also be included on the surgical claim-this is often overlooked as the claim is coded with the surgical diagnosis only.  A claim audit should be performed to ensure the capture of any systemic disease condition if the anesthesiologist or CRNA has added a P modifier.



Revenue code 370

This revenue code includes the anesthetic itself and any necessary materials whether disposable or reusable.

Outpatient anesthetic agents having a HCPCS should be billed with revenue code 636.   Anesthetic agents without a HCPCS can be billed under 370.  Some payers will reimburse for these drugs separately.  Please review any fee schedules and billing guidelines from your contracted payers.

Charges for anesthesia equipment should not be reported as a separate charge. The cost of equipment should be part of the OR charge.



Anesthesia time is defined as the period during which an anesthesia practitioner is present with the patient. It starts when the anesthesia practitioner begins to prepare the patient for anesthesia services in the operating room or an equivalent area and ends when the anesthesia practitioner is no longer furnishing anesthesia services to the patient, that is, when the patient may be placed safely under postoperative care.




  • Medicare (100-04/Chapter 12/Section 50 G) 
    • Actual Anesthesia time in minutes is reported on the claim.  For anesthesia services furnished, the A/B MAC computes time units by dividing reported anesthesia time by 15 minutes.
  • Nebraska DHHS (471 Manual/Chapter 18/18-004.33D5)
    • The services were personally provided by the physician to the individual patient; or
    • When the physician provided medical direction for CRNA services, the number of concurrent services directed is indicated by the appropriate modifier.
    • Claims for these services must indicate actual time in one-minute increments.
  • Blue Cross Blue Shield Nebraska (Provider Manual, page 75: December 15, 2017)
    • The total anesthesia allowed amount is an accumulation of base units plus time units. Base units will be internally assigned by BCBSNE using the American Society of Anesthesiologists (ASA) Relative Value Guide based on the CPT anesthesia procedure code submitted. Every 15 minutes is considered one time unit. LIST ONLY TOTAL NUMBER OF MINUTES IN THE UNITS FIELD. DO NOT LIST CALCULATED TIME UNITS NOR START/STOP TIMES ON THE CLAIM.
    • The base units + time units are calculated by BCBSNE’s claims processing system. Reporting time units in the units field can result in an underpayment.


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