These websites have been selected for their breadth of knowledge on various tests and procedures. All information is free to access.
Consumer health A-Z list of tests & procedures to find out what it is, how it's done, how to prepare, and the risks and results.
See: Diagnosis & Therapy. Read about symptoms, causes, treatment and prevention for over 975 diseases, illnesses, health conditions and wellness issues. MedlinePlus health topics are regularly reviewed, and links are updated daily.
Clinical procedures reference tool for medical professionals.