[ss1996]

No, I meant what Gymbeaux said.

Since Fentanyl is so potent, it's mixed in such low volume. The dosage is still high enough to kill you due to the potency.

Let's assume the desired drug to fentanyl ratio is 1000:1 by volume. When you take a small random sample of this, there's a good chance that 0 parts of Fentanyl have been selected in this random sample. You'll get a clean test result, even though the drug contains lethal amounts of Fentanyl.