How long does it take for glucose to show in your wee?

[OneOfMyTurnsComingOn]

Just had cereal with sugar on. Need to do a sample. Does anyone know if it will show so soon?

If you need to do a fasting sample for some reason then you'll have to wait. But unless you're diabetic or have gestational diabetes there won't be any sugar in your wee regardless of what you eat. So if it's a standard sample you'll be fine.

Ah ok. Cos sometimes I've been to midwife and had a trace and they've asked what I've eaten. If I've said I had a Mars bar or sugary drink they've used that to explain it away. I'm just hoping to avoid the GTT.

It is quite possible to have sugar in your urine without being diabetic or having gestational diabetes. It is normal in pregnancy for your kidneys to leak some sugar into your bloodstream, if you have just eaten or drank something sweet.
If you do get a +sugar result though, it probably doesn't hurt to cut down a bit on the sweet stuff in general...