when was patient 26286 tested for a lab test for the first time since 07/2105?
select labevents.charttime from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 26286 ) and strftime('%y-%m',labevents.charttime) >= '2105-07' order by labevents.charttime asc limit 1