what lab tests did patient 23721 have for the first time since 02/2104?
select d_labitems.label from d_labitems where d_labitems.itemid in ( select labevents.itemid from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 23721 ) and strftime('%y-%m',labevents.charttime) >= '2104-02' order by labevents.charttime asc limit 1 )