how many times does since 85 months ago patient 80645 get a creatinine clearance test?
select count(*) from labevents where labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'creatinine clearance' ) and labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 80645 ) and datetime(labevents.charttime) >= datetime(current_time,'-85 month')