Adulteration
Definition
Deliberate tampering of a urine specimen to defeat the screen. Common adulterants include nitrite, chromate, peroxide, glutaraldehyde, niacin, vinegar and Visine. Detected by specimen-validity testing of pH, specific gravity, creatinine and oxidisers.
- Detection method
- Specimen-validity testing
- Parameters checked
- pH, specific gravity, creatinine, oxidisers
- Common agents
- Nitrite, chromate, peroxide, glutaraldehyde
- Other agents
- Niacin, vinegar, Visine
Common questions
Why does creatinine matter in specimen-validity testing?+
A creatinine reading far below the expected physiological range signals the sample was diluted, either by the donor drinking excess water or by adding water directly to the collection cup.
What is the practical effect of a positive adulteration finding?+
Most laboratory and workplace testing protocols treat an adulterated specimen as equivalent to a positive or refused test, since the tampering itself defeats the purpose of the screen.
Related terms
- Confirmatory Test
- A test with sufficient specificity to establish the identity of a biological fluid for reporting purposes. Examples include Takayama and Teichmann crystal...
- Cut-Off Concentration
- The threshold analyte concentration, set by regulatory guidance, above which a specimen is reported as a screen-positive. Choosing the cut-off balances sensitivity...
- Detection Window
- The period after last use during which a drug or its metabolite is detectable in a given matrix. Varies from minutes (blood,...
- EMIT
- Enzyme-Multiplied Immunoassay Technique. Homogeneous immunoassay where drug-enzyme conjugate competes with drug in the sample for antibody binding; free conjugate retains enzyme activity,...
- MRM
- Multiple Reaction Monitoring. LC-MS-MS or GC-MS-MS mode that follows specific precursor-to-product ion transitions for each target analyte, giving very high selectivity at...
- SAMHSA-5
- The five-drug federal workplace panel of the US Substance Abuse and Mental Health Services Administration: amphetamines, cocaine metabolite, marijuana (THC-COOH), opiates and...
- Screening Test
- A fast, sensitive immunoassay (EMIT, CEDIA, FPIA, KIMS, lateral-flow) that flags a sample as presumptive positive against a class cut-off. Sensitive and...