By Katie Pillion
Vice President, Genesis Background Screening Services
You’re already performing drug tests on your applicants, and that’s a great step for better hires. But how can you be sure that your testing is accurate? Here are a few tips to strengthen your drug screening program:
First, check the tech. A reputable screening program will have a two-step process: Immunoassay, followed by GC-MS (Gas Chromatography Mass Spectrometry) analysis. If the immunoassay is negative, no further testing is necessary – the candidate is negative for drugs. If the sample tests positive in the immunoassay, then GC-MS analysis is performed. This second test identifies the specific drug substances and the amount present in your applicant’s specimen. This second test should be used before reporting positive drug results, because it will provide pin-point accuracy that many “instant read” products on the market are unable to achieve. It will also detect even the smallest amounts of illicit substances. So, make sure that the tests that you use have GC-MS confirmation of all positive test results.
Second, collect carefully. False negatives can be caused by dilution of the candidate’s specimen, or the use of urine alternatives. Crafty applicants will add water found in the collection center (like from the toilet or the sink) to their specimen jars to force a false negative. A quick Google search will reveal hundreds of products on the market claiming to be a suitable urine substitute for quick-read drug tests, which the applicant will add to their specimen cup at the collection center.
How do you beat this? The key is in the way that the collection center handles specimen collection. One option is to do “observed collections” where a nurse remains in the room with the candidate while they provide a specimen. This isn’t appealing to everyone, and so another alternative is to do a few initial tests on the specimen as soon as it is collected. This includes checking the temperature of the specimen as soon as it is collected, since a urine substitute will not read at normal internal body temperatures. The testing facility should also prep the collection areas with toilet water that has been dyed so it cannot be added to a specimen container.
Third, beat the clock. Alright, you’ve determined that the test you’re using is solid, and the collection center uses the best practices in specimen sampling. But you may still get false negative test results. Why? Because of basic human metabolism. Most drugs metabolize, that is they break down and are processed out of the body, in about 72 hours from last use.* This means that the candidate that had a negative drug test on Friday may have been using drugs on Tuesday if he took the time to detox.
Stopping this type of false negative takes careful timing. Streamlining your hiring process can help you get to the drug testing phase quickly, reducing the likelihood of your applicant being able to detox before the testing time. Choose a background check provider who has partnered with local labs and collection sites that have been thoroughly vetted so that you can send the candidate in for a drug test near her home. Set a firm 72 hour time limit for collection of the specimen. Decrease the amount of time between asking the candidate to take the test, and when they actually go into a clinic.
*The one exception to the 72-hour time limit is Marijuana, which can take up to 3 months to fully metabolize out of the body.