How to calculate anesthesia time and reporting CMS 1500 and EDI


Anesthesia time begins when the anesthesiologist starts to prepare the patient for the procedure. Normally, this service takes place in the operating room, but in some cases, preparation may begin in another location (i.e., holding area). Anesthesia time is a continuous time period from the start of anesthesia to the end of an anesthesia service. In counting anesthesia time, the anesthesia practitioner can add blocks of time around an interruption in anesthesia time as long as the anesthesia practitioner is furnishing continuous anesthesia care within the time periods around the interruption.

The following calculations are used when processing claims for anesthesia services:
Rev. 01/2010 14 Anesthesia Time

1. The 15-minute time interval will be divided into the total time indicated on the claim. Total time should always be accurately reported in minutes. Actual time units will be paid; no rounding will be done up to the next whole number – only round to the next tenth.


95 MINUTES   ** 15 = 6.33 = 6.3
79 MINUTES   ** 15 = 5.26 = 5.3

2. The total units derived from Step 1 will constitute total units for time.

3. The time units will be added to the relative value units (base units) assigned to the anesthesia procedure code.

4. Total units derived from Steps 1–3 will then be multiplied by the conversion factor. The final step will result in the calculation amount compared to the billed charge.

Medicare will make payment based on 80 percent of the lesser of the two amounts, subject to the application of the yearly deductible.

The anesthesia relative value (base unit), actual anesthesia time and appropriate conversion factor will be utilized for payments of anesthesia services.

Anesthesiologists and CRNAs must report anesthesia time in total minutes in Item 24G of the CMS-1500 claim form or the electronic equivalent. Complete all other items as required according to the CMS-1500 claim form instructions.

Loop 2400/SV104 (MJ)
Anesthesia/Oxygen minutes

CMS-1500 Example:
If total time for anesthesia is one hour, enter 60 minutes in Item 24G.

BCBS calculation of Anesthesia Units Base Units

BlueCross uses the Medicare base units as a basis for procedures.

Time Units

Providers should report anesthesia time units in minutes. BlueCross calculates the number of units for claims adjudication based on 15-minute increments, rounded to the nearest tenth (1/10). For example, we would calculate 49 minutes as follows:

49 minutes/15 increment = 3.266 units

3.266 would round to 3.3 time units

We do not provide anesthesia benefits for:

* The administration of anesthesia for non-covered services, such as cosmetic surgery.

We do not provide separate benefits for the following if in conjunction with other surgical or medical services:

* Pre-operative anesthesia consultation
* Transesophageal cardiography
* Emergency intubation
* The administration of anesthesia by the attending surgeon or surgical assistant, except as outlined above
* Local anesthesia

Anesthesia Payment & Billing Information

Time and Points Eligible Anesthesia Procedures Defined

Blue Cross and Blue Shield of Texas has determined that certain anesthesia procedures will be reimbursed on time and points methodology.

Procedures that are not included on the Anesthesia Time & Points Eligible List will not be reimbursed using time and points methodology. If a procedure is not on this list, and it is submitted using anesthesia indicators for Time & Points such as:

• using an anesthesia modifier, or

• using time on the claim, or

• if submitted on a non-HIPAA claim format, (Type of Service = 7),

then the provider may receive a denial message for that procedure noting that the service is not eligible for time and points payment methodology.

Anesthesia Services

Services involving administration of anesthesia should be reported by the use of the Current Procedural Terminology (CPT) anesthesia five-digit procedure codes, American Society of Anesthesiologists (ASA) or CPT surgical codes plus a modifier. Blue Cross and Blue Shield of Texas will require that the appropriate anesthesia modifier be filed on anesthesia services.

An anesthesiologist or a CRNA can provide anesthesia services. The anesthesiologist and the CRNA can bill separately for anesthesia services personally performed. When an anesthesiologist provides medical direction to a CRNA, both the anesthesiologist and the CRNA should bill for the appropriate component of the procedure performed. Each provider should use the appropriate anesthesia modifier.

In keeping with the American Medical Association Current Procedural Terminology (CPT) Book, services involving administration of anesthesia include the usual pre-operative and post-operative visits, the anesthesia care during the procedure, the administration of fluids and/or blood and the usual monitoring services (e.g., ECG, temperature, blood pressure, oximetry, capnography and mass spectrometry). Intra-arterial, central venous, and Swan-Ganz catheter insertion are allowed separately.

Payment Calculation Information

Time Units Time units will be determined by using the total time in minutes actually spent performing the procedure.Fifteen minutes is equivalent to one (1) time unit.  Time units will be rounded to the tenth. Therefore, if the procedure lasted 49 minutes, the time units in this example would be 3.26 or 3.3 time units. The units field 24G of the CMS-1500 form should reflect the number of minutes the provider spent on the procedure, (e.g. one hour-thirty minutes should be reflected as (90) in the units field).

Anesthesia time begins when the provider of services physically starts to prepare the patient for induction of anesthesia in the operating room (or equivalent) and ends  when  the  provider  of  services  is  no  longer  in constant  attendance  and  the  patient  may  safely  be placed under postoperative supervision.

Base Points The basis for determining the base points is the Relative Value  Guide  published  by  the  American  Society  of Anesthesiologists  (ASA).  HMO  Blue  Texas  and  Blue Cross  and  Blue  Shield  of  Texas  shall  implement  any yearly  update  of  the  Relative  Value  Guide  within  60 days of receipt. Base points used to process claims will be  the  base  points  in  effect  on  the  date(s)  Covered Services  are  rendered.  The  exception  to  this  will  be Covered Services provided on dates between the receipt of  the  Relative  Value  Guide  published  by  ASA  and implementation of   the   updated   material.   Claims incurred  during  the  exception  period  will  be  priced based  on  the  Relative  Value  Guide  in  effect  on December  1st of  the  prior  calendar  year.  Newly stablished codes will be paid at HMO Blue Texas and Blue Cross and Blue Shield of Texas determined rates until the annual update is implemented.

Anesthesia Time Reporting – Medicaid Guide

Report anesthesia time in minutes.  
**  Electronic claims
**  Enter total time in minutes in the “minutes” field with the correct MJ (anesthesia minutes) qualifier 
**  Paper claim forms 
** CMS-1500 
**  Enter the minutes in Box 24G.  
**  Put an “M” before the minutes
**  Example: M531 
** If a claim is submitted without minutes or the correct MJ qualifier, Medicaid pays one time unit, i.e., 12 minutes or less

Obstetrical Anesthesia – Time Reporting 

Obstetrical neuraxial anesthesia for planned vaginal delivery is unique in that the anesthesiologist may attend more than one patient concurrently under continuous regional anesthesia.  There is a reduction in the unit value after the first hour of anesthesia time.

Example: For the first hour, 5 time units is calculated; for the second hour, 2.5 units; for the third and each succeeding hour of anesthesia, 1.25 units.  

When billing obstetrical anesthesia, indicate total time in minutes.  The Medicaid Management Information System (MMIS) calculates the appropriate reduction in unit value.  

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