Blood tests are useful tools for uncovering disorders in the human body, including neurological abnormalities. Blood tests may be ordered to screen for a disease before symptoms appear, help determine a diagnosis, monitor the progression of a disease and monitor the effectiveness of a patient’s treatment.

Common blood tests include:

• Complete blood count (CBC). Measures the number of red blood cells, white blood cells (WBC), hemoglobin, hematocrit and platelets. When a CBC is ordered with a differential, there is an evaluation of the different types of WBCs in the blood.
  
  
• C-reactive protein test and sedimentation rate. Detects general inflammation.
  

Blood tests are performed routinely to diagnose or monitor various neurological conditions. For example, blood tests can reveal signs of brain or spinal cord infection that leads to illnesses such as encephalitis and meningitis. Many other neurological conditions or symptoms require blood tests before a definitive diagnosis can be made.

Blood test results are always evaluated in relation to the “normal range” for that test. The range of values considered to be normal is based on the range of test results from the blood of normal, active healthy people.

Most blood tests require little or no preparation, and patients can generally return to their usual daily activities afterward. Additional diagnostic tests such as urine tests, imaging tests or biopsies may be necessary to confirm a diagnosis.