I take hydrocodone and I also tested for oxycodone I haven't taken oxycodone how is that possible?

I take hydrocodone and i also tested for oxycodone i haven't taken oxycodone how is that possible?

Happens all the time. It is called a cross-reaction meaning one drug registers as another. Hydrocodone is well known for cross-reacting with opiate immunoassays and particularly with Oxycodone panels:

See:
Medical Laboratory Observer (MLO) p. 24 (http://www.mlo-online.com/ebook/A1go1l/MLO0910/resources/26.htm)

All of the national drug testing laboratories are well aware of this problem. As example Redwood Toxicology (RTL) makes special note of the phenomenon in their Potential Reactants and Cross-Reactants Chart available here. > LINK (http://www.redwoodtoxicology.com/documents/products/cross_reactions.pdf)

Hospital laboratories (as distinguished from commercial) are also aware (ex. Pathology Department, Borgess Hospital, Kalamazoo, MI) > LINK (http://www.ncsconline.org/wc/publications/res_judedu_substanceabusematerial19pub.pdf) and

Univ. of Mich, UMHS Guidelines for Clinical Care > LINK (http://www.med.umich.edu/1info/FHP/practiceguides/pain/drugtesting.pdf)

Many OTC/home or on-site Oxycodone tests make specific note of Hydrocodone as possibly causing a “false positive” see > LINK (http://www.hydrocodonedrugtest.com/)as well as > LINK (http://www.drugtestingworld.com/oxycodone-iscreen-drug-test-kit-urine-oxy-p-31.html)

This is not an unusual occurrence, there are hundreds of published articles, practice guidelines and professional advisories.

What is unusual is that the testing laboratory and or the doctor requesting the test for Hydrocodone would be unaware of this common phenomenon.

In fact, the test that you were administered would have had a package insert (required by law) that would make specific note of this potential for Oxy/Hydrocodone cross-reactivity.