what was the time of patient 83225's last laboratory test in the first hospital visit?
select labevents.charttime from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 83225 and admissions.dischtime is not null order by admissions.admittime asc limit 1 ) order by labevents.charttime desc limit 1