had there been any organism found in patient 15821's last sputum microbiology test?
select count(*)>0 from microbiologyevents where microbiologyevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 15821 ) and microbiologyevents.spec_type_desc = 'sputum' and microbiologyevents.org_name is not null order by microbiologyevents.charttime desc limit 1