Haven't been able to eat much at all due to anxiety and depression . lost weight. what blood test will be off due to this?

Hormones and NTs: Currently there are no lab tests that can be used to diagnose people with any psychiatric disorder including depression/anxiety. We can however measure mediators (mechanisms) that might contribute to these serious symptoms. In addition to usual blood work (including thyroid panel), I use specialty lab kits to measure neurotransmitters (urine) and adrenal and sex hormones (saliva).

See below: Tests may or may not reflect the degree of malnutrition. Seek an evaluation by a psychiatrist for an eating disorder, so diagnosis and treatment can follow.