Thank you for your question regarding CMS871v4, Hospital Harm - Severe Hyperglycemia. This measure does not assess hemoglobin A1c (HbA1c) results. When assessing blood glucose results, the measure assesses specimen sources of blood, serum, plasma, or interstitial fluid that are expressed in mass/volume units and are obtained by a laboratory test, a point-of-care (POC) test, or a continuous glucose monitor (CGM).   The measure uses the ["Laboratory Test, Performed": "Glucose Lab Test Mass Per Volume"] QDM data element ( https://ecqi.healthit.gov/mcw/2025/ecqm-dataelement/laboratorytestperformedglucoselabtestmasspervolume.html ). For more information on the types of glucose test results and specimen sources that are considered by the measure, users may review the LOINC codes included in the “Glucose Lab Test Mass Per Volume” value set (OID: 2.16.840.1.113762.1.4.1248.34) on the Value Set Authority Center (VSAC).   If a patient has a blood glucose result of greater than 300 mg/dL from a qualifying specimen source, this may qualify the patient’s inpatient hospitalization for the measure’s numerator, as the measure’s numerator criteria are defined as inpatient hospitalizations with a hyperglycemic event within the first 10 days of the encounter minus the first 24 hours, and minus the last period before discharge from the hospital if less than 24 hours. The measure defines a hyperglycemic event is defined as a day with at least one glucose value greater than 300 mg/dL, OR a day where a glucose test and result was not found, and it was immediately preceded by two contiguous, consecutive days where at least one glucose value during each of the two days was greater than or equal to 200 mg/dL.