instruction: how many hours have elapsed since the last time patient 14154 in this hospital encounter received a lab test for anion gap?
response: SELECT 24 * (STRFTIME('%j', CURRENT_TIME()) - STRFTIME('%j', labevents.charttime)) FROM labevents WHERE labevents.itemid IN (SELECT d_labitems.itemid FROM d_labitems WHERE d_labitems.label = 'anion gap') AND labevents.hadm_id IN (SELECT admissions.hadm_id FROM admissions WHERE admissions.subject_id = 14154 AND admissions.dischtime IS NULL) ORDER BY labevents.charttime DESC LIMIT 1