[Soterik]

I'm on the periphery of a situation where a person was arrested and tested for drugs. The blood/urine tests all came back negative.

While I've been told that there are street drugs that can't be tested for... do they really exist? I've done a few searches, but am not really coming up with anything useful.

The blood/urine draw was at less than 2 hours from the arrest. The person arrested exhibited clear signs of being under the influence of drugs.

Thanks...