A blood test is read as a check on what lies beneath the surface — a wish to know the truth, or worry about being judged or found lacking.
When this appeared in your dream, what were you feeling?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.