what is until 04/2105 maximum albumin, body fluid value of patient 31300?
select max(labevents.valuenum) from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 31300 ) and labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'albumin, body fluid' ) and strftime('%y-%m',labevents.charttime) <= '2105-04'