Categorizing the Charges
While the American Society of Anesthesiologists (ASA) Relative Value Guide establishes the ground rules for the calculation of anesthesia charges by establishing base values for all surgical services and appropriate guidelines for the determination of time units, not all billed units have equal value in the payment of anesthesia services. This is because anesthesia charges fall into three categories: time-based surgical charges, obstetric charges and non-time-based charges for flat fee services (such as invasive lines, acute pain blocks, and evaluation and management services).
Time-based surgical services are paid based on base and time units, which is consistent with most contract payment terms. Obstetric services typically rely on ASA base values, but time unit calculations vary based on a number of conventions such that they rarely correspond to actual clinical time spent with the patient. For non-time-based services, most payments are based on a fee schedule that has little or nothing to do with the ASA base values. Because of this, a calculation of a yield per unit that simply divides total units billed by total payment posted during a given period of time will not be accurate or very useful.
Calculating the Charges
The best way to calculate the actual yield per unit is to isolate time-based surgical units and the actual payments related to surgical services. The result of such a calculation is especially useful for the evaluation of the payment per unit for each contract although it is important to understand that other factors, such as co-payments and deductibles, may affect actual payment amounts. The reason it is so important to isolate surgical services is because OB and flat fee services will always have different payment conventions.
This is not the end, though. There are two conventions that apply to payment posting: DOE and DOS. Date of entry payments only show when the payment is posted so there is no correlation between the date of the service and the date of the payment. For Date of Service payment posting, there is a direct correlation by month of the service and the payment. The most accurate yield calculations are by DOS; however, one must remember that there will be a lag between the date of service and the posting of related payments. Typically, it will take at least six months for claims to be reasonably adjudicated.
Sometimes these calculations can be done based on DOE, but these will require a larger period, such as a year. Such calculations will have more value for annual performance comparisons—specifically, to compare yields from one year in the past to another—in other words, only for an annual trend analysis.