And find out below does a cold affect blood tests.ĭoctors can order blood tests for a variety of reasons. If you need to book blood work, book an appointment today to have this blood work performed from the comfort of your home. This makes it essential to talk with your doctor or the health practitioner administering the test about your cold to find out if you need to postpone your blood work until after you recover. Depending on what your doctor hopes to evaluate, your cell counts can change during a cold. These normal bodily processes can affect the results of certain blood tests. The common cold is a viral or bacterial infection that causes your body to respond in various ways.