what specimen test has been given this month to patient 26286 for the first time?
select microbiologyevents.spec_type_desc from microbiologyevents where microbiologyevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 26286 ) and datetime(microbiologyevents.charttime,'start of month') = datetime(current_time,'start of month','-0 month') order by microbiologyevents.charttime asc limit 1