instruction: when was the first sputum microbiology test performed for patient 12410?
response: SELECT microbiologyevents.charttime FROM microbiologyevents WHERE microbiologyevents.hadm_id IN (SELECT admissions.hadm_id FROM admissions WHERE admissions.subject_id = 12410) AND microbiologyevents.spec_type_desc = 'sputum' ORDER BY microbiologyevents.charttime LIMIT 1