If somebody was sick and you were testing their blood would you be able to tell what was wrong with them?

Question: If somebody was sick and you were testing their blood would you be able to tell what was wrong with them?
- Keywords:
  blood,
  health,
  human body,
  test,
  work
Asked by Sarah207 to Armin on 20 Nov 2019.
- Armin Shams answered on 20 Nov 2019: last edited 20 Nov 2019 9:12 am
  
  Not my field, but I have read that blood is a very rich source of information about human health condition.

Question: If somebody was sick and you were testing their blood would you be able to tell what was wrong with them?