The BANA test.

Some of the bacteria that cause periodontal disease (gum disease) produce waste products that are quite odiferous and as a result contribute to a person's breath problems. The presence of some of these types of bacteria can be tested for by way of performing a BANA test.

The bacteria in question have the characteristic of being able to produce an enzyme that degrades the compound benzoyl-D, L-arginine-naphthylamide (abbreviated BANA). When a sample of a patient's saliva that contains these bacteria is placed in with the BANA testing compound they cause it to break down, thus creating a color change in the testing medium.