Cholesterol, glucose (diabetes testing), anemia, blood typing, drug testing, pregnancy testing, hormone testing and almost all other types of blood tests. Some tests can be done on-site, with results in minutes!
A partial list of tests that can be done same day include:
Influenza and swine flu
Pregnancy testing
Urinalysis
Helicobactor pylori
HIV screening (please note that a positive result will require laboratory confirmation, which can take up to 5 days)