Brazwell et al reported a false positive urine screen for oxidants during drug testing in patients with a urinary tract infection, usually in women. The authors are from Tricore Reference Laboratories in Albuquerque, New Mexico.
The situation presents with a positive adulterant screen for oxidants.
The authors found that E.coli, Klebsiella and Pseudomonas could cause the false positive reaction.
A specimen giving a false positive reaction often may have had a delay during transport, allowing for overgrowth of bacteria.
Response:
(1) A positive screening test for oxidants should be confirmed if relevant.
(2) The patient should be evaluated for a urinary tract infection.
(3) Urine testing could be repeated with a new specimen collected under direct observation.
(4) Hair testing can help to determine if the person has used a drug of abuse in the past (there is a lag time of 7-10 days from the time of drug use before it is present in an emergent hair).
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