Thank you for your question regarding CMS871v4: Hospital Harm - Severe Hyperglycemia. Your assessment is correct that the measure considers the glucose result of 326 mg/dL from a test on May 10 at 11:03 to fall on eligible hospital day 1 and considers the glucose result of 352 mg/dL from a test on May 11 at 5:12 to fall on eligible hospital day 2. Therefore, based on the information provided, and assuming that the inpatient hospitalization for the patient met the initial population/denominator and numerator criteria and did not meet the denominator exclusion/numerator exclusion criteria, then measure observation 2 would return two (2) hyperglycemic event days for this inpatient hospitalization. When evaluating for days with a hyperglycemic event, the first 24-hour period after admission to the hospital is not evaluated to account for potentially poor glucose control outside of the hospital setting or that preceded the start of hospital care. For this measure, hospital days are not defined as midnight-to-midnight. Rather, they are defined as full 24-hour periods that start at the beginning of the hospitalization (including emergency department and observation), excluding the last period before inpatient discharge from the hospital if that period is less than 24 hours. To illustrate how hospital days are defined, the scenario you provided is outlined in the table attached below by eligible hospital days.