###HUMAN: give me the number of patients whose admission type is emergency and lab test name is creatine kinase, mb isoenzyme?, ###ASSISTANT: SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic INNER JOIN lab ON demographic.hadm_id = lab.hadm_id WHERE demographic.admission_type = "EMERGENCY" AND lab.label = "Creatine Kinase, MB Isoenzyme"