Yes, stress can affect CBC results. This test is done to evaluate the overall health of a person and detect any medical disorders. A high level of stress affects the lymphocyte level, red blood cell count, and platelet count. Stress can cause many conditions, such as depression, anxiety, or psoriasis. The WBC count increases with an increase in symptoms of such a medical condition. A normal CBC test result indicates that the blood cell parameters are in the reference range. A higher or lower test result indicates an underlying medical condition or low vitamin levels.