when did the last lab test of patient 29741 until 22 months ago happen?
select labevents.charttime from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 29741 ) and datetime(labevents.charttime) <= datetime(current_time,'-22 month') order by labevents.charttime desc limit 1