Hello WorriedScared, 

Blood tests can't usually diagnose cancer but they can be really important to check your general health, including how well your liver and kidneys are working, check numbers of blood cells and help diagnose cancer and other conditions. You can read more about blood tests on this page and the types of blood tests available and what they are for. 

It's best to talk to your GP though about what tests you might need as they will be in the best position to tell you and offer you advice based on your symptoms. Do mention to your doctor too that you feel a bit nervous about blood tests - you can also look away when they take blood if you prefer if it helps you feel less anxious about it; this way you don't even have to see the blood.

I hope your blood tests go well and that they will help shed some light on what is going on. 

Best wishes, 

Lucie, Cancer Chat Moderator