Thank you for reaching out with your question regarding CMS347v8. The guidance section in the header in the measure specification outlines a process to prevent counting patients in more than one of the four populations. When implementing this measure, if you were unable to identify patients for Initial Population 4 but are implementing the measure as specified, it could mean that either no patients meet the criteria for Initial Population 4 or that all patients were captured in Initial Populations 1-3. For reference, I have included the guidance for each Initial Population that is published in the measure header:   Initial Population Guidance: The initial population covers four distinct populations. Use the following process to prevent counting patients more than once.   Initial Population 1: All patients who were previously diagnosed with or currently have a diagnosis of clinical ASCVD, including an ASCVD procedure before the end of the measurement period.   - If YES, meets Initial Population 1 risk category. - If NO, screen for next risk category.   Initial Population 2: Patients aged 20 to 75 years at the beginning of the measurement period who have ever had a laboratory test result of LDL-C >= 190 mg/dL or were previously diagnosed with or currently have an active diagnosis of familial hypercholesterolemia.   - If YES, meets Initial Population 2 risk category. - If NO, screen for next risk category.   Initial Population 3: Patients aged 40 to 75 years at the beginning of the measurement period with an active diagnosis of Type 1 or Type 2 diabetes at any time during the measurement period.   - If YES, meets Initial Population 3 risk category. - If NO, screen for next risk category.   Initial Population 4: Patients aged 40 to 75 at the beginning of the measurement period with a 10-year ASCVD risk score of >= 20 percent during the measurement period.   - If YES, meets Initial Population 4 risk category. - If NO, patient does NOT meet Initial Population criteria and is NOT eligible for measure inclusion.   Initial Population Guidance for Encounter: In order for the patient to be included in the Initial Population, the patient must have ONE initial population-eligible visit, defined as follows: outpatient visit, initial or established office visit, face-to-face interaction, preventive care services, or annual wellness visit.   LDL-C Laboratory test result options: The measure can be reported for all patients with a documented LDL-C level recorded as follows:   To meet Initial Population 1: There is no LDL-C result required.   To meet Initial Population 2: If a patient has ANY previous laboratory result of LDL-C >= 190 mg/dL, report the highest value >= 190 mg/dL.   To meet Initial Population 3: There is no LDL-C result required.   To meet Initial Population 4: There is no LDL-C result required.   The 10-year ASCVD risk assessment options: The 10-year ASCVD risk score is calculated using the Pooled Cohort Equations: 1) the 2013 ACC/AHA ASCVD Risk Estimator (maps to LOINC Code 79423-0) OR 2) the ACC Risk Estimator Plus (maps to LOINC Code 99055-6). If your EHR does not have either of these risk calculators, we recommend that you use the on-line versions. The 10-year ASCVD risk score (quantitative result, i.e., result.value, "%") must be documented in a structured field. The 10-year ASCVD risk assessment must be performed during the measurement period.