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Î All samples undergoing definitive testing should be tested for
creatinine concentration, pH level and specific gravity (if creatinine
is low).
Signs of Urine Sample Tampering
Î All urine samples should be checked for unusual specimen
characteristics. Characteristics include:
• Temperature outside the expected range of 90–100°F within 4 minutes of
production (this can be checked using a heat sensitive strip).
• Unusual color or smell, soapy appearance, cloudiness or particles floating in
the liquid.
Î If a urine sample exhibits unusual specimen characteristics, the
sample should undergo specimen validity testing to help identify
whether and how tampering occurred.
Responding to Specimen Validity Test Results
Î Providers should consider samples that have been tampered with to
be presumptive positive.
Î For patients with past incidences of dilute urine samples, it is
advisable to collect samples in the morning or request that patients
decrease water intake prior to sample collection.
Î For patients with past incidences of dilute urine samples, use creative
solutions, such as collecting before work, on days off, or use an
alternative matrix.
Urine Testing for Specific Substances
Î Urine testing for the use of alcohol is appropriate with current clinical
tools. Ethyl glucuronide (EtG) is an appropriate target metabolite when
monitoring a patient for complete alcohol abstinence.
• Ethanol-containing products, including hand sanitizers and mouthwash, should be
avoided before an EtG test.
Î Urine testing is helpful when assessing amphetamine use. Particular
caution should be paid to the interpretation of amphetamine
immunoassays due to known limitations in specificity.
Î Urine testing is helpful when assessing benzodiazepine use.
• Particular caution should be paid to the interpretation of benzodiazepine
immunoassays due to known limitations in specificity.
• Immunoassay results should be used cautiously when monitoring a patient's
adherence to prescribed benzodiazepines. If a patient reports that he or she is
taking the drug but a urine drug screen is negative, further analysis using definitive
testing should be considered.
