A urine sample screens positive for opiates (cutoff = 300 ng/mL) and positive for oxycodone (cutoff = 100 ng/mL). The confirmation yields a positive result for oxymorphone only. Which is the most likely explanation for the screen results?

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Please select the single best answer

	There is cross-reactivity of oxycodone in the opiate class screen.
	The presence of oxymorphone in the confirmation is a false positive.
	The absence of any other opiates beside oxymorphone in the confirmation is a false negative.
	The screen cutoff is lower than the confirmation cutoff.