There are always questions regarding Drug Tests/Urine
Tests, that sort fo thing. If we put any info or
experiences we have under one thread it'll make it easier
to find.
Claude..if you find that list of drugs that can cause false
positives maybe you could post it here when you have time.
I'll start with this one I found in The Journal of the
American Medical Association on:
Doctors and other health professionals must
pay greater attention to the potential for common medications to
cross-react with frequently-used testing assays for substance
abuse.
Millions of assays are performed in various
settings each year to monitor for substance abuse. However,
cross-reactions of licit drugs with assays for illicit ones are
not uncommon and produce false positives results that, in turn,
lead to invalid conclusions.
These researchers sought to
evaluate the cross-reactivity of quinolone antimicrobials in
common opiate (urine) screening assays and to assess the in vivo
implications of this phenomenon.
The reactivity of 13
quinolones was tested in five commercial opiate screening assays
from September 1998 to March 1999.
Quinolones included
in the study were levofloxacin, ofloxacin, pefloxacin, enoxacin,
moxifloxacin, gatifloxacin, trovafloxacin, sparfloxacin,
lomefloxacin, ciprofloxacin, clinafloxacin, norfloxacin, and
nalidixic acid.
The researchers confirmed the
cross-reactivity of levofloxacin or ofloxacin with these
opiate-screening assays in six healthy volunteer study
participants.
Main outcome measure was opiate assay
activity (threshold for positive result, 300 ng/mL of
morphine).
In at least one of the assays, nine of the
quinolones caused assay results above the threshold for a
positive result. Four of the assay systems caused false-positive
results for at least one quinolone.
Of the 13 compounds,
11 caused some opiate activity by at least one assay system. At
least one compound caused opiate assay activity in all five
assay systems.
Levofloxacin, ofloxacin, and perfloxacin
were most likely to lead to a false-positive opiate result.
Positive results were obtained in urine from all six
volunteers.
To minimize the potential for invalid test
interpretation, greater attention must be paid to the
cross-reactivity of quinolones with immunoassays for opiates,
these researchers conclude.
JAMA. 2001;286:3115-3119.
"Quinolones and False-Positive Urine Screening for
Opiates by Immunoassay Technology"