You can do it in the US as well. You can buy fentanyl test strips easily. https://dancesafe.org/drug-checking/ https://dancesafe.org/drug-checking/ That said

You can do it in the US as well. You can buy fentanyl test strips easily. https://dancesafe.org/drug-checking/ https://dancesafe.org/drug-checking/ That said, how many users actually test every single drug they purchase? Especially if they are addicted and using multiple times per day?