One of venous thromboembolism (VTE) measures uses the QDM datatype Procedure, Performed with an ordinality of principal.  The intent is to identify the principal procedure. The principal procedure is the procedure performed for definitive treatment rather than diagnostic or exploratory purposes, or which is necessary to take care of a complication. https://manual.jointcommission.org/releases/TJC2015B/DataElem0685.html

In consideration of how to represent this same concept in FHIR, and to determine how existing EHR vendors address the concept, ESAC reviewed the UB-04 and determined field 74 is specified for entering the ICD code and date of the principal procedure.  But UB-04 is not a clinical tool.  Asking several vendors how the address principal procedure yielded the following results:

EHR Vendor 1:

There is way to identify a principal procedure other than by looking at the claim.  The reason why there is no record of what is the principal procedure in the clinical chart is because it has no clinical meaning. It was probably invented some years ago by somebody at Medicare for some purpose, but it is only meaningful for billing.

EHR Vendor 2:

ICD-10-CM procedure codes are captured in the database by using EHR applications or transmitted through an inbound interface. Only one procedure code may be identified as a Principal Procedure Code. The Principal Procedure Code is recognized as the active code on the Procedures table with a priority equal to 1. The procedure codes should represent the Principal and Other Procedure Codes submitted with the billing claim for each patient episode of care. 

Data Warehouse Vendor:

We get it from the encounter "discharge abstract" coded data and merge with the clinical record. That is the only consistent way to get this at present.

Summary:

It seems that vendors can find the information but that it is not generally entered as a clinical concept and most are finding the information using a vendor-specific method.

This QDM ticket is generated to identify additional input from implementers about how to identify a principal procedure in a manner that reduces burden to clinicians and implementers.