My wife who is in her early 40s, seems to be worried about her health and she wants to have a blood test to get 'everything checked', such as cholesterol levels and risk of a cancer and stroke etc. Do you think she should ask the doctor/nurse for advice on what type of blood test to have? If so, the doctor/nurse may advice for the bare minimum type of test since there have been huge cutbacks on NHS spending.
I think the starting point is to go to see the doctor for your wife to express her concerns. The doctor would then determine what blood tests would be advisable for her to have. I would expect the doctor to take her blood pressure.
A blood test can be specific to one condition or it can incorporate readings specific to the health and function of a number of organs / glands etc., for example:-
these tend to be the most common ones that are tested which can all be done at one appointment with the nurse.
If there is a breathing problem, oxygen saturation levels and peak flow tests can be done also at the surgery.
No one can advice what tests can be done only a G.P. whom your wife has consulted as it is he / she who authorizes them.
I think as said I would start with a doctors appointment and see if they have any concerns, they can do a general check up on health and will voice any concerns they have this may be enough to set your wifes mind at ease, but if not some of the private hospitals offer health checks at different levels with screening included, they aren't cheap but could also be worth a look.