A hospitalist is a doctor who works only in a hospital setting. Hospitalists care for patients who are staying in the hospital to recover from an illness or a surgery. Most hospitalists are also internists, and many primary care doctors are hospitalists. Some of them also work in subspecialties or have work in other areas early in their careers. Hospitalists coordinate care for patients admitted in the hospital. They play the role of Primary care doctors in hospital settings.

A nephrologist is a medical professional who specializes in diagnosing and treating diseases and disorders that affect the kidneys. Nephrologists are often referred to as kidney specialists. Some nephrologists also do research that helps them learn more about kidney diseases, so they can produce better treatments for their patients.