when patient 10266 was receiving a lab test for the first time when they visited the hospital first time?
select labevents.charttime from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 10266 and admissions.dischtime is not null order by admissions.admittime asc limit 1 ) order by labevents.charttime asc limit 1