Guidelines are an important part of medical writing and accessing a large variety of updated ones can enable you to be more thorough on the topic you are writing about. Some guidelines are not necessarily updated to reflect recent scientific finds. A good example of this is trying to determine an acceptable range for TSH test results in patients being screened for thyroid health. Acceptable range values can differ considerably from one guideline to the next making it a little tricky when writing about it.
The U.S. Department of Health and Human Services’ Agency for Health care and Services (AHCS) provides the National Guidelines Clearinghouse, a useful database of clinical practice guidelines.