Episode 23: Drug Tests Don’t Mean What You Think — Methamphetamine Edition


In this episode of the Critical Science podcast, Dr. Lyle Burgoon discusses the topic of drug testing, with a focus on methamphetamine testing. He explains the different forms of methamphetamine and how they affect the brain. Dr. Burgoon highlights the presence of levomethamphetamine in over-the-counter products and the potential for false positive methamphetamine tests. He emphasizes the importance of accurately listing all medications, including over-the-counter drugs, when undergoing drug testing. Dr. Burgoon also explores the probability of drug use based on positive test results and the challenges of interpreting drug tests. He concludes by emphasizing the need for due diligence and additional confirmatory tests in the drug testing process.


Methamphetamine has two forms: levo and dextro, with only the dextro form having psychoactive effects on the brain.
Over-the-counter products containing levomethamphetamine can lead to false positive methamphetamine tests.
Positive drug tests do not necessarily indicate drug abuse, as there is a high probability of non-users testing positive.
Confirmatory tests, such as enantiomer-specific tests, are necessary to accurately determine the presence of methamphetamine.


00:00 Introduction to Drug Testing
00:28 Different Forms of Methamphetamine
01:53 How Methamphetamine Affects the Brain
03:10 Levomethamphetamine in Over-the-Counter Products
04:07 Ramifications of Positive Methamphetamine Tests
05:59 Forgetting to List Over-the-Counter Drugs
06:26 Drug Testing in Various Settings
07:24 Probability of Drug Use Based on Positive Test
08:20 Bayes’ Rule and Prevalence of Drug Users
09:46 Probability of Positive Test for Non-Users
12:37 Performance Characteristics of Drug Tests
13:34 Low Probability of Drug Use Given Positive Test
16:37 High Probability of Non-Users Testing Positive
18:10 Challenges of Drug Testing and Confirmatory Tests
20:27 Enantiomer Specific Test for Methamphetamine
23:21 Additional Steps in Drug Testing Process
25:31 Importance of Due Diligence in Drug Testing
26:01 Positive Test Does Not Indicate Drug Abuse
26:58 Orthogonal Assay for More Accurate Results
27:25 Conclusion and Closing Remarks

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