what was the last value of the creatinine lab test for patient 74624 during their last hospital visit?
select labevents.valuenum from labevents where labevents.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 74624 and admissions.dischtime is not null order by admissions.admittime desc limit 1 ) and labevents.itemid in ( select d_labitems.itemid from d_labitems where d_labitems.label = 'creatinine' ) order by labevents.charttime desc limit 1