when did patient 65484 have the last lab test during their first hospital visit?
select labevents.charttime from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 65484 and admissions.dischtime is not null order by admissions.admittime asc limit 1 ) order by labevents.charttime desc limit 1