instruction: how many hours have elapsed since the last time in the current hospital visit patient 006-80884 has been given a rdw lab test?
response: SELECT 24 * (STRFTIME('%j', CURRENT_TIME()) - STRFTIME('%j', lab.labresulttime)) FROM lab WHERE lab.patientunitstayid IN (SELECT patient.patientunitstayid FROM patient WHERE patient.patienthealthsystemstayid IN (SELECT patient.patienthealthsystemstayid FROM patient WHERE patient.uniquepid = '006-80884' AND patient.hospitaldischargetime IS NULL)) AND lab.labname = 'rdw' ORDER BY lab.labresulttime DESC LIMIT 1