Anesthesia Coding Alert

Hint: In anesthesia, MAC can refer to two very different things.

Whether you’re new to anesthesia coding or you need a refresher, you’ll need to know this information to make sure the claims you’re preparing make sense.

Shannon Cameron, MBA, MHIIM, CPC, shared some nitty-gritty details on anesthesia coding in her HEALTHCON 2025 presentation “Deep Dive Into Anesthesia.” Keep reading to find answers to these anesthesia-specific billing questions.

Question: What are the different types of anesthesia?

Answer: There are three categories of anesthesia:

• General: When general anesthesia is administered, the patient is unconscious and has no sense, sensation, or awareness. The different types of delivery include intravenous or inhalation.
• MAC: Monitored anesthesia care (MAC) describes when an anesthesia provider monitors the patient’s vitals carefully, but the patient is less deeply sedated and may still be responsive and breathe on their own. This type of anesthesia is used for minor procedures that do not require general anesthesia.
• Regional: Regional anesthesia involves an injection of anesthetic medication to a specific part of the body to numb or relieve pain or to enable surgical procedures; sedatives may be given in addition to the injection. These procedures include spinal anesthesia, like epidurals and nerve blocks.

Question: Can you report two types of anesthesia services for the same procedure or date of service?

Answer: When multiple service types, like a spinal or epidural, as well as MAC, are provided, then both services should be reported — but any postoperative pain blocks would not be billable, Cameron explained.

“You must clearly document a note if the block was used for anesthesia plan or for the postoperative pain management,” she said.

Question: What codes are appropriate for qualifying circumstances in anesthesia services?

Answer: Qualifying circumstances are different from anesthesia physical status modifiers, but there are sometimes payments attached to these circumstances, Cameron said.

Status B codes aren’t eligible for separate reimbursement; many payers consider them incidental and already included in the payment. Some payers, including Medicare, might not recognize these codes at all, she said.

Qualifying circumstance codes include:

• 99100 (Anesthesia for patient of extreme age, younger than 1 year and older than 70 (List separately in addition to code for primary anesthesia procedure)), 1 unit
• 99140 (Anesthesia complicated by emergency conditions (specify) (List separately in addition to code for primary anesthesia procedure)), 2 units
• 99116 (Anesthesia complicated by utilization of total body hypothermia (List separately in addition to code for primary anesthesia procedure)), 5 units
• 99135 (Anesthesia complicated by utilization of controlled hypotension (List separately in addition to code for primary anesthesia procedure)), 5 units

Question: Do Medicare and other commercial payers use different equations for payment for anesthesia services?

Answer: In her presentation, Cameron said Medicare generally doesn’t give any credit for modifying factors.

Accordingly, their anesthesia payment equation looks something like “base unit + time units = total units.”

However, depending on your respective contract with participating commercial payers, their payment equation may look like “base unit + time units + modifying factor units = total units.”

Question: What should a provider cover in an anesthesia preoperative evaluation?

Answer: Cameron said when you’re conducting a pre-anesthesia evaluation, you’ll need to do so within a 48-hour timeframe and include, at a minimum, the following elements:

• Review of medical history, including anesthesia, drug, and allergy history
  • Document any pertinent diagnoses that support P2 status (if applicable), like if the patient is obese or currently smokes tobacco
• Interview of the patient, if possible
• Examination of the patient
  • Minimally: Heart, lung, airway, dental
• Notation of anesthesia risk, according to established standards of practice
• Identification of potential anesthesia problems, especially any that may suggest complications, like an ongoing infection or a compromised airway or intravascular access

Use all of these elements to develop a plan for the patient’s anesthesia care. Don’t forget the type of medication for induction (which is a condition of participation per Medicare policy), the maintenance and postoperative pain management, and discussion with the patient or their respective representative about the risks and benefits of anesthesia care, Cameron said.

“We also ran into this a little bit in audits, which is medical direction for the pre-evaluation. This is another area that’s a high level of focus for auditing: Requirements indicate that the physician must evaluate and examine the patient, and the physician must personally examine the patient. So, if you’re in a teaching facility, you have to be really careful about that,” Cameron said.

And make sure you include those other crucial elements of documentation: signature, date, and time.

Rachel Dorrell, MA, MS, CPC-A, CPPM, Development Editor, AAPC