Sorry about that Questions › Category: Questions › Sorry about that 0 Vote Up Vote Down Robert asked 4 years ago I take 30 mg morphine every 12 hrs TweetShareSharePin0 Shares 1 Answers 0 Vote Up Vote Down PainDr Staff answered 4 years ago That dose of morphine and timing would never be negative with a reliable test. You doctor is probably correct, that the devices are inaccurate and unreliable.