The former Leeds midfielder could now be hit with a six-month ban if his B sample also proves positive.
And that will probably signal the end of a career that began at Everton.
The troubled 26-year-old will travel to London this week and argue his case in front of FA disciplinary chiefs.
And even if the second sample is positive, he still has the right to appeal.
Cadamarteri, now in his second spell at Bradford City, has also played for Sheffield United.