Anesthesia and Fee Calculation

by  Christine Woolstenhulme, QCC, QMCS, CPC, CMRS
January 29th, 2018

Fees for anesthesia services are not calculated or reported the same as for other types of procedures, we have identified some of the most common rules used for reporting anesthesia in this article. Please refer to your MAC Carrier, third-party payer, and the AMA guidelines for more detailed information. 

Conscious Sedation

If conscious sedation is being provided by the same physician doing the procedure refer to codes 99151-99153

If there is another physician administering the moderate conscious sedation with a separate physician performing the procedure in a facility setting, the other physician may report codes 99155-99157 NOTE: These not reported for services in a physician's office or freestanding imaging center, for services in the office, home, hospital or consult see the Evaluation Management section 99201-99499

Multiple Procedures

When multiple procedures are performed at the same time under the same anesthesia, code the most complex procedure and add the total time for all procedures during the same encounter. 

Status Code

If you are not getting the desired fees expected, be sure to check the status code and payment indicators (Located under Additional Code Information - PURPLE tab). For example, a CPT code with a "J" status code is indicating the following;

"Anesthesia Service: There are no RVUs and no payment amounts for these codes. The intent of this value is to facilitate the identification of anesthesia services."

APC Status Indicator

The APC Status Indicator code will also give information on how the code should be used. for example, Status Code "N" indicates the following;
"Service Items and Services Packaged into APC Rates, and the procedure is, "Paid under OPPS; payment is packaged into payment for other services. Therefore, there is no separate APC payment."

Calculating Anesthesia Fees

When you are on an anesthesia code information page the Anesthesia Fee Calculation can be found on the GREEN Fees tab. 

There are four elements to consider when calculating anesthesia fees. Medicare accepts base units and time units; however, depending on the third-party payer, they may or may not accept physical status units and/or qualifying circumstances units.

  1. Base Unit (of the CPT code)
  2. Time (in 15-minute increments)
  3. Physical Status (P1P2P3P4P5P6)
  4. Qualifying Circumstances (four CPT add-on code options: 99100991169913599140)

FindACodes fee calculator for Anesthesia units can be found on the code information page on the code you need pricing for. The calculator uses Medicare conversion factors based on geographical location and calculates fees from the base unit and amount of time reported, which may or may not include physical status modifiers and qualifying circumstances.


Base unit for 00820: 5
Time units for 45 min: 45min/15min = 3
Physical Status: N/A
Qualifying circumstances: N/A
Conversion factor: $22.05
5+3=8 units        8 units X $22.05 = $176.40 Medicare Allowed

Physical Status Modifiers

Physical Status Modifiers is a classification system under the classifications and guidelines used for more than 60 years by the American Society of Anesthesiologists to communicate a patients' pre-anesthesia medical co-morbidities. 

For example, 

If the private payer accepts Physical Status (PS) and/or Qualifying Circumstances (QC) as units, these may also be included as part of the fee calculation. Below, the general value of units is shown with each PS Modifier or QC add-on code. Assigning these modifiers and CPT codes may affect payment, for example, according to Moda Health and Unitedhealthcare, they follow the standard Anesthesia Formula below

NOTE: Medicare does not recognize Physical status modifiers, Always check the payer policies to see if these rules apply and if the unit values are different:

PS Modifier: Value QC Modifiers: Value
P1: 0 99100: 1
P2: 0 99116: 5
P3: 1 99135: 5
P4: 2 99140: 2
P5: 3  
P6: 0  

American Society of Anesthesiologists ranking of patient physical status, which can also be found at the ASA web site

REF: "Using Physical Status Modifiers with Anesthesia Codes"

Qualifying Circumstances for Anesthesia

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)
99116 Anesthesia complicated by utilization of total body hypothermia (List separately in addition to code for primary anesthesia procedure)
99135 Anesthesia complicated by utilization of controlled hypotension (List separately in addition to code for primary anesthesia procedure)
99140 Anesthesia complicated by emergency conditions (specify) (List separately in addition to code for primary anesthesia procedure)

Other Modifiers

CMS and other payers require the use of the following modifiers, these are used by qualified non-physician anesthetists when billing for anesthesia services:

These MUST be billed in the first position:

REF: Anesthesia Documentation Modifiers CMS Pub-100 

NOTE: The QS modifier can be used by a physician or a qualified non-physician anesthetist and is for informational purposes. Providers must report actual anesthesia time and one of the payment modifiers on the claim.

For more information on CMS billing with modifiers and Anesthesia Billing see the Pub 100-04 Medicare Claims Processing Manual

Find-A-Code recently added Fees for anesthesia using the applicable Base Units from CMS, UCR, and ACA.  This information can be found on the Anesthesia code information page under Fees and Anesthesia Fee information. To change from CMS to UCR simply select the down arrow next to the Anesthesia Base Units. 


Anesthesia and Fee Calculation. (2018, January 29). Find-A-Code Articles. Retrieved from

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