Home test kits can detect marijuana in cannabis products. Here’s how one works

Test kits that can detect cannabis can be purchased for at-home use.

The Star-Telegram, for an article looking into the availability of delta products, used kits from SwabTek, a San Diego based company that sells a variety of kits to a variety of drugs, like cocaine, fetanyl and heroin. The kit purchased online by the Star-Telegram for $125 included 25 tests for THC. Delta products can be bought at convenience stores and smoke shops and can produce a high to varying degrees, as they contain different types of THC, the chemical that produces a high.

The company sells two kits that can test cannabis products. One, the Cannabis test kit, will detect whether a substance contains cannabis — be it marijuana or industrial hemp. It turns red if cannabis is present and doesn’t differentiate between which specific chemical is being found.

The second is a THC kit, which tests specifically for delta-9, the chemical most commonly associated with producing a high. If there’s more than 0.3% by dry weight in a product, it is marijuana and illegal in Texas unless prescribed for medical reasons. Less than that, and it’s hemp.

The test uses a tool to heat up a sample of the product and melt it into a powder that reacts with a reagent. If it turns yellow, green or blue, the product tests positive for delta-9. The color it turns indicates the THC concentration.

Eleven products purchased at stores around Tarrant County were tested. Four were edible gummies and the others oil used in vaping devices. We tested delta-8, -9, -10 and delta-11 products.

In the course of testing, it became clear that the tests did not work best with gummy products because they contain colored dyes that can make the tests hard to read. Another option was using a provided cotton swap to wipe the gummies for oil residue. We did both.