Usually, you need to fast for 8 hours. No food or water intake. Depende sa OB mo kung papayagan ka uminom, pero sakin she didn't allow me. Procedure kasi sakin before dapat last meal mo before 12 am, before mag 8 nasa hospital ka na dapat. By exactly 8 am, kukuhanan ka ng dugo. Yun ang FBS. Every hour, may ipapainom sayo na glucose syrup and kukuhanan ka ng dugo for three times.