This testing will not be automatically performed with a drug screen order; the ordering clinician must specifically request urine adulterant testing. Specimen adulteration is the manipulation of a sample that may cause falsely negative test results for the presence of drugs of abuse. Common adulterants that may affect testing are water, soap, bleach, vinegar, oxidants, and salt. The adulteration testing includes assessment of creatinine concentration, pH, urine specific gravity, presence or absence of an oxidant, and presence or absence of nitrite. Test sent to Mayo Clinic Laboratories.