Diagnostic tests and procedures are vital tools that help physicians confirm or rule out the presence of a neurological disorder or other medical condition. This chapter deals with the discussion on neurological diagnostic test which include laboratory screening tests, genetic testing, and neurological examination. Blood, urine, or other substances are used to help diagnose disease, better understand the disease process, and monitor levels of therapeutic drugs. Analysis of the fluid that surrounds the brain and spinal cord can detect meningitis, acute and chronic inflammation, rare infections, and some cases of multiple sclerosis. Genetic testing help parents who have a family history of a neurological disease determine if they are carrying one of the known genes that cause the disorder or find out if their child is affected. They include amniocentesis, chorionic villus sampling, and uterine ultrasound. Neurological examination assesses motor and sensory skills, the functioning of one or more cranial nerves, hearing and speech, vision, coordination and balance, mental status, and changes in mood or behavior, among other abilities.