I'd like to request clarification of the denominator logic for CMS53v3 in regards to the ANDing of "Occurrence A of Diagnostic Study, Result..." (DSR) so I'll do my best to make my questions as clear as I can.

The CMS implementation guide states regarding specific occurrence logic:

“When a specific occurrence of an event is specified in multiple clauses linked by AND logic, the logic is only satisfied if the ANDed logical statements evaluate to true using a specific (single) instance of the event.”

Considering the following logic branch:

• AND: "Occurrence A of Diagnostic Study, Result: Hospital Measures-ECG (result: 'Hospital Measures-Acute or Evolving MI')"
• AND NOT:
  • AND: "Occurrence A of Diagnostic Study, Result: Hospital Measures-ECG (result: 'Hospital Measures-Acute or Evolving MI')"
  • AND: "Occurrence A of Diagnostic Study, Result: Hospital Measures-ECG (result: 'NSTEMI')" // redundant logic
• AND NOT: "Occurrence A of Diagnostic Study, Result: Hospital Measures-ECG (result: 'NSTEMI')"
• AND: FIRST:"Occurrence A of Diagnostic Study, Result: Hospital Measures-ECG" starts after start of "Occurrence A of Diagnostic Study, Performed: Hospital Measures-ECG"

The QRDA template for a DSR only allows for 1 value (Result). Since Occurrence A may only refer to one DSR across the ANDed logic, Occurrence A may not have multiple results (unless multiple DSR entries may be linked together to form a composite DSR - in which case how should that linking be done?) If we cannot reliably link multiple DSR templates in the QRDA document, how do we account for the logic that says Occurrence A of DSR (result: Acute or Evolving MI) AND NOT Occurrence A of DSR(result: NSTEMI)? Since a specific occurrence may only have a single result, it would seem that the AND NOT logic should be removed or the "Occurrence A" restriction should be removed from the "AND NOT DSR (result: NSTEMI)" statement.

I apologize in advance for the confusing question. Please let me know if I need to clarify.