Which substances does an employer test? 5-panel vs 10-panel

"Which substances are actually tested?" It is the first question most people ask before having a drug test, whether for a job application or for personal certainty. The answer depends on the panel: the number of substance groups the test screens for. The two most used are the 5-panel and the 10-panel, and the difference is bigger than just a number.

Worth knowing up front: there is no single worldwide list that defines "the 5-panel". The classic, internationally known composition comes from American occupational medicine. In the Netherlands, a reliable laboratory prefers to look at what is actually used here. That is why the Zuivertest panel deliberately differs from the American standard. Below you will read both, so you know exactly what you are testing.

The international 5-panel and 10-panel

The internationally known panels come from the American SAMHSA guideline (Substance Abuse and Mental Health Services Administration) for workplace testing. The 5-panel screens for five substance groups, the 10-panel adds five more. This composition is set in law for federal employees in the United States and has become the global reference framework.

What stands out: PCP, propoxyphene and methaqualone have been on the American list for decades, but barely play a role in the Netherlands. The Trimbos Institute, the Dutch knowledge centre for substance use, reports very different use patterns in its National Drug Monitor than those in the US. Copying a panel wholesale from another country therefore produces a test that watches for the wrong substances.

The Zuivertest 5-panel and 10-panel

That is why Zuivertest uses a composition suited to Dutch use. The core 5-panel covers the five most requested substances, and the extended 10-panel adds five more that bring less common and newer substances into view.

The difference from the American list is deliberate. Substances such as 3-MMC, ketamine and GHB appear in Dutch nightlife and among designer drugs, while a classic American 10-panel does not measure them. We consider a panel that matches the Dutch reality more valuable than an international label that misses half the relevant substances.

Which panel fits your question?

The choice depends on what you want to know, not on which number sounds highest. A few practical guidelines:

• Targeted certainty about common substances. If you want a short, clear answer about the most common substances, the 5-panel is usually enough.
• Broad view or unknown exposure. If you are unsure about less common or newer substances, or want to be as complete as possible, the 10-panel offers more coverage.
• One specific substance. If you care about a single substance, you can also choose a separate screening instead of a full panel.

Bear in mind that no panel tests "everything". A test only measures the substances it is set up for, and only within the detection window of that substance. How long a substance stays detectable varies greatly per substance and per matrix (urine, blood or hair).

How long does a substance stay detectable?

The detection window determines whether a substance is found at all. The indicative times below apply to urine after occasional use. With frequent or heavy use they are higher, sometimes considerably. The RIVM and the Trimbos Institute stress that factors such as dose, frequency of use, metabolism and body composition strongly influence the window.

These are indicative times, not guarantees. A hair test looks back much further than urine, sometimes months, while blood shows a short, recent window. Read more about those differences in how long do drugs stay detectable and in what is a cut-off value in a drug test.

May an employer simply choose a panel?

A common misconception is that an employer can freely impose any panel. In the Netherlands this is nuanced. According to the Autoriteit Persoonsgegevens and the framework of the Working Conditions Act (Arbowet), health data are special personal data, and in most roles an employer may not simply test for drugs or alcohol. A legal basis exists only for certain regulated professions. You will find the full legal framework in workplace drug testing: what your employer may do and in can your employer require a drug test.

The advantage of an independent test is that you choose the panel yourself, only you see the result, and you decide whether to share it. That keeps you in control, instead of someone else deciding which substances are examined.

Every test result at Zuivertest includes a professional assessment from a BIG-registered doctor. A drug test can provide clarity, but does not replace medical advice. For treatment decisions, discuss your results with your GP.

Sources

• Trimbos Institute, National Drug Monitor, substance use in the Netherlands (trimbos.nl)
• RIVM, information on drugs and detection (rivm.nl)
• Autoriteit Persoonsgegevens, "Testing for alcohol, drugs or medicines during work time" (autoriteitpersoonsgegevens.nl)