Precision analysis to eliminate doubt    

Substantiate results through confirmatory testing

Mayo Clinic Laboratories’ definitive testing approach utilizes mass spectrometry technology to accurately identify parent drugs and metabolites of substances, which, because of complex metabolic processes, similar chemical structures, and pharmaceutical impurities, could interfere with the results of immunoassay screening. Our fast and cost-effective definitive tests are available in a variety of configurations, including individually, for each drug of abuse class.

Our approach to confirmatory testing enables providers the flexibility to perform immunoassays locally, while enabling confidence through definitive testing that ensures optimal patient care. Our individual drug confirmations yield quantitative results that can be useful for managing complex cases, including instances where testing results are questioned or denied. Test reports identify specific drug findings and their concentrations.

Urine confirmatory testing is available for:





CNS Depressants




CNS Stimulants

Amphetamine-Type Stimulant


Methylphenidate (Ritalin)

Other illicit substances

Marijuana (THC)

Phencyclidine (PCP)

For a list of available confirmatory serum tests, check out our test catalog.

Learn more about how to order these tests at your institution.