Nah dude, you're good. Employers typically outsource drug tests to private labs that run 10 panel tests, which include:
1. Amphetamines (and Methamphetamine)
2. Barbiturates
3. Benzodiazepines
4. Cannabinoids
5. Cocaine
6. Methadone
7. Methaqualone
8. Opiates
9. PCP
10. Propoxyphene
Your employer may perhaps run a 12 panel test, which will differentiate between methamphetamine and amphetamine, as well as opiates and oxycodone. It will also detect Tricyclic Antidepressants.
Unless your employer is an athletic organization with a stated anti-doping policy, you're good to go.