when has patient 1489 received the first lab test during their last hospital visit?
select labevents.charttime from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 1489 and admissions.dischtime is not null order by admissions.admittime desc limit 1 ) order by labevents.charttime asc limit 1