GPs can’t take and analyse blood tests on the spot - hospitals can.
Your son needs blood and urine tests and probably a chest X-Ray to rule out anything serious.
I feel so blessed that the (second) GP who looked at my daughter had the ability to put her ego to one side and admit that she didn’t understand why my daughter wasn’t getting better, and we should go to a&e to have tests - when I spoke to her after my daughter had come out of intensive care she was blown away that it had been so serious (around 40% of kids with my daughter’s illness die within weeks of diagnosis).
I realise my daughter’s situation makes me very biased towards the ‘go to a&e’ side of the argument, but until this happened I was the kind of mum that would insist my kids go to school rain or shine, and that they should get the school to call me to collect them if they still felt bad at lunchtime.
Honestly, if my husband hadn’t said that he really thought my daughter should see another doctor ASAP (she’d been once a couple of days before) I probably would’ve left it.
We’re home now but are looking at a very long outpatient treatment period and a slow recovery - other parents on my daughter’s oncology ward tell similar stories of ‘we thought it was just a virus’.
I wouldn’t risk anything, knowing what I know now!