There are 4 common tests to determine organic pollution in wastewater: BOD (or CBOD), COD, TOC, and Oil & Grease (O&G).
Grease-clogged sewer pipe.
Oil & Grease testing determines the amount of non-volatile hydrocarbons (i.e. petroleum derivatives), vegetable oils, animal fats, waxes, soaps, greases and related material in a sample. Another name that better describes the test is n-Hexane-Extractable Materials (HEM), as this test measures only what is extractable by the solvent n-hexane.
There are two types of O&G reporting: TOTAL O&G (HEM Oil& Grease) or POLAR/NON-POLAR (SGT-HEM; Non-polar Material). "Non-polar" materials are the portion of the oils and greases that derive from petroleum products. "Polar" is everything else. Requesting the polar/non-polar option gives an idea of the source of your O&G contamination. It requires an extra step in the method, and so costs a bit more.
O&G testing is most often requested by water treatment facilities and industries whose processes generate fats and oils. O&G released to the environment not only clogs pipes, it's bad for aquatic life, and creates ugly slimes.
-- from Michigan Department of Environmental Quality
Resoures
Cole Parmer's Environmental Express, "Understanding Oil and Grease" (.pdf)
EPA Method 1664, Revision B (2010, 35 pg. pdf)
Michigan Department of Environmental Quality, "Oil and Grease" (powerpoint)
"Cease the Grease" webpage from Berwick Sewer District