Specimen tampering is a deliberate malicious attempt to subvert the drug test and is an ongoing concern for urine drug testing. There are several products which, when added to the urine specimen, either degrade the drug or interfere with the testing protocol, or both. Some of these products are found around the house (bleach and detergent, for example) and many are purchased commercially. Some of these products shift the pH of a urine specimen. Shifting the pH of a specimen may degrade drugs present in the sample or may interfere with the analysis of a specimen, or both. Some adulteration products are classified as oxidants. Oxidants present in a urine specimen may degrade drug present or may interfere with the analysis of a specimen, or both.