what was the first specimen test that was given to patient 55624 until 37 months ago?
select microbiologyevents.spec_type_desc from microbiologyevents where microbiologyevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 55624 ) and datetime(microbiologyevents.charttime) <= datetime(current_time,'-37 month') order by microbiologyevents.charttime asc limit 1