count the number of patients who were tested since 1 year ago for bilirubin, total, body fluid.
select count( distinct admissions.subject_id ) from admissions where admissions.hadm_id in ( select labevents.hadm_id from labevents where labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'bilirubin, total, body fluid' ) and datetime(labevents.charttime) >= datetime(current_time,'-1 year') )