Thank you for your inquiry regarding CMS996: Appropriate Treatment for ST-Segment Elevation Myocardial Infarction (STEMI) Patients in the Emergency Department (ED). We understand the intent of your question is to clarify whether specific cases fall within the measure denominator and/or numerator. Please see responses to each respective question below: 1. In regard to the first question, diagnoses may be found in a patient’s problem list, encounter diagnosis list, claims data, or other sources within the EHR. A patient with a STEMI diagnosis may be captured in the measure in two ways, as indicated by the measure logic definition below found in the measure’s HTML file posted on the eCQI Resource Center [ https://ecqi.healthit.gov/sites/default/files/ecqm/measures/CMS996-v6.3.000-QDM.html ]. ED Encounter with STEMI Diagnosis "ED Encounter During MP" EDEncounterinMP     where (exists (["Diagnosis": "STEMI"] DxSTEMI       where DxSTEMI.prevalencePeriod starts during EDEncounterinMP.relevantPeriod))     or (exists( EDEncounterinMP.diagnoses EncounterDiagnosis       where EncounterDiagnosis.code in "STEMI" )) First, a STEMI diagnosis can be pulled directly from the ED encounter if a STEMI diagnosis was coded during the encounter. Second, the patient can have a diagnosis pulled from a claim, problem list, or other source in the EHR as long as the prevalencePeriod of the STEMI diagnosis started during the ED encounter relevantPeriod. PrevalencePeriod is an attribute of the “Diagnosis” datatype and signifies the onset dateTime to abatement dateTime of the STEMI diagnosis. RelevantPeriod is an attribute of the “Encounter, Performed”: “Emergency Department Evaluation and Management Visit” datatype and signifies the startTime that the encounter began (admission time) to the stopTime that the encounter ended (discharge time). In the scenario described in the inquiry, the patient’s first ED encounter (occurring on 2/11) should be included in the measure numerator and denominator since the patient had a STEMI documented in the EHR during the measurement period, and the patient received PCI within 90 minutes of ED arrival. In terms of the second ED encounter occurring on 2/15, it is possible that this encounter may also be captured in the measure denominator. First, the measure may pull a STEMI diagnosis if it was recorded in the patient’s problem list. To prevent this and to differentiate between active and historic diagnoses in the problem list, it’s important for both the onset and abatement times to be populated in the EHR and mapped to the appropriate QDM data elements to avoid misattribution. Second, the measure may pull a historic STEMI diagnosis if it was recorded as an encounter diagnosis. This issue has been previously brought to CMS attention. We highlight that the QDM does not prescribe a presentOnAdmissionIndicator attribute for the “Diagnosis” datatype. However, the measure developer team may consider using a presentOnAdmissionIndicator attribute for the “Encounter, Performed” datatype in a future Annual Update. 2. To answer your second question, a discharge to acute care within 45 minutes of ED arrival at the same facility can count towards the measure numerator. To indicate that the ED encounter has ended, we recommend proper documentation of ED discharge time and the ED discharge disposition of “Discharge to Acute Care Facility.” 3. In terms of the last question, two denominator exceptions were added to Version 6 of the STEMI measure for the 2026 reporting period to accommodate patients who received an initial STEMI diagnosis but were then determined not to have a STEMI diagnosis after being taken to the cardiac catheterization laboratory. The measure has exceptions for (i) ED encounters with a documented reason for not administering fibrinolytic therapy within 30 minutes of ED arrival, and (ii) ED encounters with a documented reason for not performing PCI within 90 minutes of ED arrival. Please find the definitions for these exceptions below, which can also be found in measure’s HTML file posted on the eCQI Resource Center [ https://ecqi.healthit.gov/sites/default/files/ecqm/measures/CMS996-v6.3.000-QDM.html ]: ED Encounter With A Documented Reason For Not Administering Fibrinolytic Therapy Within 30 Minutes Of ED Arrival "ED Encounter With STEMI Diagnosis" EDwSTEMI    with (["Medication, Not Administered": "Fibrinolytic Therapy"] NoFibrinolytic           where (NoFibrinolytic.negationRationale in "Patient Refusal" or NoFibrinolytic.negationRationale in "Drug Intervention Not Indicated/Contraindicated")) FibrinolyticRefused     such that FibrinolyticRefused.authorDatetime during EDwSTEMI.relevantPeriod ED Encounter With A Documented Reason For No PCI Performed Within 90 Minutes Of ED Arrival "ED Encounter With STEMI Diagnosis" EDwSTEMI     with (["Procedure, Not Performed": "Percutaneous Coronary Intervention"] NoPCI           where (NoPCI.negationRationale in "Patient Refusal" or NoPCI.negationRationale in "Procedure Not Indicated/Contraindicated")) PCIRefused     such that PCIRefused.authorDatetime during EDwSTEMI.relevantPeriod The denominator exception for not administering fibrinolytic therapy within 30 minutes of ED arrival is defined using the negationRationale attribute of the “Medication, Not Administered” QDM datatype. Reasons for not administering fibrinolytic therapy are captured in the “Patient Refusal” (OID: 2.16.840.1.113883.3.117.1.7.1.93) and “Drug Intervention Not Indicated/Contraindicated” (OID: 2.16.840.1.113762.1.4.1282.1) value sets. Therefore, clinical codes included in these value sets must be used to trigger the denominator exception rather than notes documented in the EHR. The denominator exception uses the author dateTime attribute to indicate documentation of the time the decision to not administer fibrinolytic therapy occurred. To capture this denominator exception, documentation of the reason for not administering fibrinolytic therapy within 30 minutes of ED arrival must occur during the ED encounter relevantPeriod (or the time that the ED encounter began (admission time) to the time the ED encounter ended (discharge time)). Therefore, if documentation of the reason for not administering fibrinolytic therapy occurred outside of the ED encounter, such as in the inpatient setting, the denominator exception would not be triggered. The same logic is applicable to the denominator exception for not performing a PCI within 90 minutes of ED arrival, which is also defined using the negationRationale attribute of the “Procedure, Not Performed” QDM datatype. Reasons for not performing a PCI are captured in the Patient Refusal” (OID: 2.16.840.1.113883.3.117.1.7.1.93) and “Procedure Not Indicated/Contraindicated" (OID: 2.16.840.1.113762.1.4.1282.2) value sets. Therefore, clinical codes included in these value sets must be used to trigger the denominator exception rather than notes documented in the EHR. Similar to the denominator exception for not administering fibrinolytic therapy, this denominator exception also uses the author dateTime attribute to indicate documentation of the time the decision to not perform a PCI occurred. To capture this denominator exception, documentation of the reason for not performing a PCI within 90 minutes of ED arrival must occur during the ED encounter relevantPeriod. Therefore, if documentation of the reason for not performing a PCI occurs outside of the ED encounter, such as the inpatient setting, the denominator exception would not be triggered.