Can you eat/drink before a PCR?

[JelliedHeels]

I know you can't before a lateral flow, but does anyone know about a PCR? Can't see anything on line, just about about have one and ate just now without thinking about it Wondering whether to rearrange.

we were told to wait for 20min after a meal before testing.

Some foods can give a false positive. Plus, personally, the gag reflex might have lost me my lunch..