Authentication Service. An organization, which for a fee will determine a numismatic item's genuineness. The service must be familiar with all kinds of fakes and be able to conduct several tests, both scientific and numismatic; its authenticators must have wide experience, access to genuine specimens for comparison, the scientific equipment to conduct laboratory testing on suspect items and be willing to guarantee their decision (even in court, if necessary).

The first authentication service was established in 196x and for the most part tested coins, a predominance of which were scarce dates of popular series. From this early activity more and more rare coins were submitted for certification. While this is somewhat similar to a grading service (which, for a fee, will determine the precise condition, and thusly, a market value can be determined for a numismatic specimen), testing for genuineness is necessary for both services.