How to Minimize False-Positives and False-Negatives During an Urine Drug Screening

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Screening for drugs in the urine is a typical method for determining compliance with treatments with a high potential for misuse. Both false negatives and false positives from immunoassays have the potential to result in unfavorable outcomes for patients and medical professionals. Therefore, what more steps are there to take? We are able to reduce the number of incorrect interpretations of urine drug tests if we are able to identify the drugs that lead to false negatives and false positives.

Continue reading down below.

Analyzing the Results of the Test

Patients who have their UDS findings misinterpreted run the risk of experiencing a variety of negative repercussions, including the wrongful loss of a job, the loss of qualifying from sporting activities or rehabilitation programs, the possibility of receiving inappropriate medical treatment, the possibility of facing criminal charges, and the loss of confidence from healthcare providers.


Prior to testing, pharmacists should gather a complete list of all of the patient’s prescription, over-the-counter (OTC), and herbal drugs, as well as discuss the patient’s adherence to prescriptions, in order to assist in the interpretation of UDS findings.


In addition to the possibility of false-negative UDS findings, pharmacists are obligated to take into account the possibility of false-positive UDS data and be knowledgeable about the kinds of medicines that might lead to false-positive results.

Medications That Might Have an Impact on the Urine Drug Screening

Antidepressants: Sertraline, one of the selective serotonin reuptake inhibitors (SSRIs) included in antidepressants, has been linked to producing false-positive findings for benzodiazepines, in addition to lysergic acid diethylamide (LSD), bupropion, trazodone, and venlafaxine.

Antibiotics: quinolones and rifampin have been identified to induce false positives with UDS immunoassays; ciprofloxacin, moxifloxacin, and norfloxacin demonstrated cross-reactivity to opiates due to the similar molecular structures of the two classes of drugs.

Herbals: due to the fact that morphine and codeine are generated from opium poppy seeds, the use of relatively modest amounts of poppy seeds might lead to false-positive results for opiates.

Antipsychotics: risperidone has been recorded to trigger false-positive findings for LSD;3,9 quetiapine has been shown to cause false-positive results for methadone and TCAs. These results are due to quetiapine’s structural similarity to methadone and TCAs.

OTCs: analgesics, antihistamines, cough suppressants, and heartburn drugs that are available over the counter have been demonstrated to induce false-positive results in research studies and individual case reports.

In every circumstance, medical judgment needs to be utilized in order to pick an acceptable therapeutic agent. If an immunoassay using UDS produces findings that are unexpected, a confirmatory test using GC-MS or HPLC should be performed.

Tiesha loves to share her passion for everything that’s beautiful in this world. Apart from writing on her beauty blog and running her own beauty channel on Youtube, she also enjoys traveling and photography. Tiesha covers various stories on the website.