What is Adulteration?
Adulteration is the tampering of a urine specimen
with the intention of altering the test results. The use of
adulterants can cause false negative results in drug tests by either
interfering with the screening test
and/or destroying the drugs present in the urine. Dilution may also be
employed in an attempt to produce
false negative drug test results.
One of the best ways to test for adulteration or dilution is to determine
certain urinary characteristics such
as pH and specific gravity and to detect the presence of oxidants/PCC,
specific gravity, pH, nitrite,
glutaraldehyde and creatinine in urine.
• Oxidants/PCC (Pyridinium chlorochromate) tests for the presence of oxidizing
agents such as bleach
and hydrogen peroxide. Pyridinium chlorochromate (sold under the brand name
UrineLuck) is a
commonly used adulterant.8 Normal human urine should not contain oxidants or
PCC.
• Specific gravity tests for sample dilution. The normal range is from 1.003 to
1.030. Values outside
this range may be the result of specimen dilution or adulteration.
• pH tests for the presence of acidic or alkaline adulterants in urine. Normal
pH levels should be in the
range of 4.0 to 9.0. Values outside of this range may indicate the sample has
been altered.
• Nitrite tests for commonly used commercial adulterants such as Klear or
Whizzies. They work by
oxidizing the major cannabinoid metabolite THC-COOH.9 Normal urine should
contain no trace of
nitrite. Positive results generally indicate the presence of an adulterant.
• Glutaraldehyde tests for the presence of an aldehyde. Adulterants such as
UrinAid and Clear Choice
contain glutaraldehyde which may cause false negative screening results by
disrupting the enzyme
used in some immunoassay tests.8 Glutaraldehyde is not normally found in urine;
therefore, detection
of glutaraldehyde in a urine specimen is generally an indicator of adulteration.
• Creatinine is a waste product of creatine; an amino-acid contained in muscle
tissue and found in
urine.2 A person may attempt to foil a test by drinking excessive amounts of
water or diuretics such as
herbal teas to “flush” the system. Creatinine and specific gravity are two ways
to check for dilution
and flushing, which are the most common mechanisms used in an attempt to
circumvent drug testing.
Low creatinine and specific gravity levels may indicate dilute urine. The
absence of creatinine
(< 5 mg/dl) is indicative of a specimen not consistent with human urine.