Reliability of urine drug screens: When should you consult ...

All positive tests must be confirmed with Gas Chromatography/Mass Spectrometry (GC/MS). This method is the most widely used urinalysis test. False positive results can occur from some types of over-the-counter (OTC) drugs (e.g. ibuprofen) and cold medicines as well as poppy seeds, however, confirmation testing using gas chromatography/mass ... ................
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