Online ADHD diagnoses can be highly accurate. When the results of a physical examination inform online ADHD screening, the diagnosis is generally made with high accuracy.   Still, online tests can offer provisional ADHD diagnoses to individuals. These tests consist of consultations with medical practitioners and questionnaires that indicate the likelihood that you or your child has ADHD. For the most accurate results, it’s recommended to also have an in-person physical examination with a doctor to rule out other potential causes of ADHD before or after taking an online ADHD test.   For example, various nutritional deficiencies are linked with some ADHD symptoms like lack of concentration. Such deficiencies include low magnesium levels, zinc levels, and iron levels. These nutritional deficiencies can be discovered with blood testing that your doctor may order as part of a physical examination. These nutritional deficiencies do not necessarily rule out ADHD, but they can indicate that further testing is needed before confirming an initial diagnosis.