I doubt if they are doing every blood test that has been devised. The chances are that they will be looking at the numbers of different types of blood cells - this will show up anaemia, leukaemia, and may indicate other classes of problem such as infection.
They have probably looked at kidney and liver function tests which will show up general abnormalities which would then have more detailed investigation.
Other common ones would be thyroid, diabetes, and possibly some of the rheumatoid factors such as CrP and ESR. They may have looked at a bone screen which gives calcium levels plus a marker of bone activity which can show up osteoporosis and indicate parathyroid problems.
Some tumours will show up specific tumour markers in the blood, two examples would be prostate cancer and ovarian cancer but these are usually either part of a specific screening programme or second stage tests. Some tumours, other than blood tumours, also show changes in white cell numbers but these may not be specific.
Hope this helps.
