The cases in which it is possible to give a false positive in a Civil Guard drug test

The General Directorate of Traffic has been conducting drug tests on Spanish drivers since 2010, with the aim of detecting those found behind the wheel under the influence. Each year, the Guardia Civil Traffic Group, the road patrol unit under the DGT, carries out around 100,000 drug tests .

These tests detect the presence of five narcotic substances in saliva: cocaine, amphetamines, methamphetamines, cannabis, and opiates . However, they can occasionally produce a false positive for various reasons.

Why do these false positives occur?

First, due to the high sensitivity of salivary drug tests , they can sometimes identify traces of narcotics consumed days or even weeks ago, even if the driver is no longer under the influence .

It is also possible that some commonly used medications may produce this positive result, such as painkillers, anxiolytics, or flu medications , since they sometimes use substances derived from opium in their manufacture, which leads to this false positive.

What to do if you get a false positive for drugs?

Although after testing positive for drugs, traffic officers will always perform a second test, which will be sent to the lab for analysis , it's worth requesting just in case. This result will show the number of drugs and the quantity of each substance , and will make it easier to determine if it's a false positive.

Additionally, a blood test can be requested at a medical center to rule out drug use while driving. Finally, in some cases, it's necessary to always carry a medical certificate if the prescribed medication could interfere with the test.

Fine for testing positive for drugs

The General Directorate of Traffic classifies this offense as very serious, with a fine of up to 1,000 euros and the loss of six points from the driver's license . Furthermore, Article 379 of the Penal Code specifies that "anyone who drives a motor vehicle or moped under the influence of toxic drugs, narcotics, or psychotropic substances" commits a crime against road safety.

Specifically, the offense could be sentenced to up to six months in prison, a 12-month fine, community service for up to 90 days, and "deprivation of the right to drive motor vehicles and mopeds for a period of one to four years."