Blood tests for deficiencies

I’m new to the forums & I appreciate all the great info I’ve seen so far on here! I’m not sure if this would fall more under medical then nutrition, but anyways I’ve been seeing online recently people getting blood tests to see if they’re deficient in certain vitamins/minerals & to check their hormone levels too & a lot of them I’ve seen are not cheap especially if u wanted to get them done regularly. My question to you is when u get routine blood work when u go for a yearly check up dont they check for all that stuff anyways or would that be something extra I’d have to ask my Dr about?

Routine blood work typically includes a CMP (complete metabolic panel to look at the liver and kidney’s function), a CBC (complete blood count to make sure your red and white blood cells are normal), and sometimes a lipid panel (cholesterol) and/or HbA1C (for blood sugar). We do not routinely send blood work for vitamin or mineral deficiencies unless there is clinical evidence from the physical exam, medical history, or other lab work that indicates this should be done. Same thing for various hormone levels. I would strongly recommend against getting your vitamin and hormone levels checked “just to know”, as this has many potential harms to you the patient.

What would be some of the potential harms to getting testing outside of using time and money resources?

So if we don’t get testing, what are some symptoms or signs to be aware of that may show signs of deficiency?