when did patient 8244 last receive a lab test since 12/2105.
select labevents.charttime from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 8244 ) and strftime('%y-%m',labevents.charttime) >= '2105-12' order by labevents.charttime desc limit 1