What is the protocol if a DC is ill on a GCSE exam date?

[SpellItOut]

My DC has an undiagnosed health issue that causes spells of nausea, lasting anywhere between a day and a week. We’ve been round the houses with referrals etc over the last couple of years to try to find out why, but have no diagnosis. School attendance is roughly 85%. Exam days don’t seem to be a trigger, we’ve got through EoY exams and mocks with next to no absence. But we have to plan for what happens if they are ill for a GCSE exam.

I will check with school, but I wanted to get an idea first - I report their absence, but do the exam board need a doctors note? I gather the board will extrapolate the grade from the other subject paper(s), is that correct? Genuinely worried this might wreck their chances.

Please be very careful about taking the exam when unwell. Read the regulations carefully, and discuss with the exams officer. I've seen several cases where people who were clearly not well enough were told (sometimes by well-meaning exams officers) to give it a go and they'd put in a special consideration form. That can only make a small percentage difference, so if the candidate is ill enough that they're not going to manage to complete the paper, they would usually be far better not doing it, and having the result worked out from their other papers - especially if those have already taken place - obviously if they miss all papers, no grade can be provided.

We experienced this for one my eldests A-levels. He was unable to attend due to a migraine. He has a long history of migraines, (and subsequently terrible attendance) and the school told us that a pre-emptive GP letter explaining the situation would suffice if it happened on an exam day, so we paid fifty quid to get one and handed it over.
However on the actual day it was a different matter - they said we needed a GP letter dated that day, so I had to take him down to the surgery and beg to see a doctor. (which as you know is not how they work these days) The surgery were brilliant and fit him in as an emergency - the GP wrote in his notes that he was not fit to sit any exam, and they printed those notes out for us, which I took to the school. It was a very stressful morning, and he was out of it for about four days afterwards. However he got B in the end which I was pretty impressed with!