A provisional diagnosis is a medical diagnosis by a professional based on the information provided at the moment. A doctor issues a provisional diagnosis when first presented with a case and further tests or information are required before an exact diagnosis can be determined.
Provisional means existing until being permanently replaced. Ideally, a provisional diagnosis becomes an exact diagnosis after initial testing is complete and more information is gathered. In some cases, doctors may issue a differential diagnosis presenting different scenarios based on the symptoms of the patient to rule out each possibility individually in an attempt to diagnose the patient.