Related Experiment Videos
False-positive EMIT II opiates from ofloxacin
1Department of Biochemistry, St. Boniface General Hospital, Winnipeg, Canada.
Therapeutic Drug Monitoring
|February 1, 1997
Summary
Ofloxacin, an antibiotic, can cause false-positive results in opiate screening tests. This cross-reactivity was observed in hospitalized patients and volunteers taking ofloxacin, highlighting a potential issue in drug testing.
Area of Science:
- Clinical Chemistry
- Pharmacology
- Toxicology
Background:
- Enzyme immunoassays (EIAs) are common for drug screening.
- Quinolone antibiotics are widely prescribed.
- Potential for cross-reactivity between medications and immunoassays exists.
Purpose of the Study:
- To investigate the cross-reactivity of four quinolone antibiotics with the EMIT II Opiates enzyme immunoassay.
- To determine if ofloxacin, norfloxacin, ciprofloxacin, or nalidixic acid interfere with opiate detection.
Main Methods:
- Urine samples were spiked with individual quinolone antibiotics at concentrations up to 5,000 mg/L.
- The EMIT II Opiates assay was used to screen the spiked samples.
- Clinical samples from patients on therapeutic doses of quinolones were also tested.
Main Results:
- Ofloxacin demonstrated cross-reactivity, causing false-positive opiate screening results at concentrations as low as 200 mg/L (0.16% cross-reactivity).
- False-positive results were observed in hospitalized patients and volunteers taking ofloxacin.
- Norfloxacin and ciprofloxacin did not produce false-positive results.
Conclusions:
- Ofloxacin can interfere with EMIT II Opiates immunoassays, leading to potential false-positive results.
- Clinicians should be aware of this cross-reactivity when interpreting opiate screening results in patients taking ofloxacin.
- Further investigation into the mechanism and clinical significance of this interaction is warranted.