what specimen test was given to patient 28443 in the current hospital visit for the last time?
select microbiologyevents.spec_type_desc from microbiologyevents where microbiologyevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 28443 and admissions.dischtime is null ) order by microbiologyevents.charttime desc limit 1