instruction: count the number of patients who had received a microbiological test of the biopsy until 2104.
response: SELECT COUNT(DISTINCT admissions.subject_id) FROM admissions WHERE admissions.hadm_id IN (SELECT microbiologyevents.hadm_id FROM microbiologyevents WHERE microbiologyevents.spec_type_desc = 'biopsy' AND STRFTIME('%y', microbiologyevents.charttime) <= '2104')