A culture is a test to identify microorganisms (such bacteria or fungi) that can result in an infection. A sensitivity test determines which medication, such as an antibiotic, will be most effective in treating the disease or infection. A sample of bodily fluid or tissue is added to a material that encourages microbial growth for a culture. If no germs grow, the culture is negative. It is a sign that the culture is positive if infection-causing bacteria develop. Chemical tests or a microscope may be used to determine the type of germ. In a culture, bacteria typically develop quickly (2 days), although other types of organisms, such fungi, may take longer.