Difference between a Drug Test and a Drug Screen

Updated on June 28, 2018

At first glance, a drug test and a drug screen seem interchangeable. But while the two are both important risk management tools used by companies, they do bear significant differences.

Summary Table

Drug TestDrug Screen
Highly reactive and highly selectiveHighly reactive but not highly selective
More reliableLess reliable
Slower and more expensiveFaster and more cost-efficient
More complexLess complex
Only performed at laboratoriesCan be performed at home
Utilizes a gas chromatography and mass spectroscopy equipmentUtilizes a screening assay


lab test

A drug test is a selective examination used to analyze and identify the presence of specific substances in the blood, urine, saliva and other biological specimen excreted by the body.

A drug screen, on the other hand, is an extremely reactive test used to detect the absence or the presence of drugs in urine and other substances in the body.

Drug Test vs Drug Screen

Despite their strong associations, there is a big difference between a drug test and a drug screen.

Reactivity and Selection Process

A drug test and a drug screen are both highly reactive to specific substances present in the body. However, unlike a drug test, a drug screen is not highly selective and is, therefore, limited in making distinctions between different types of drugs.


A drug screen’s limited ability to accurately distinguish between drugs and metabolites makes it vulnerable in the area of producing a false positive result – especially once sinus medications and other over-the-counter drugs are present in the bloodstream. A drug test, by contrast, is less likely to produce inaccurate results since it selectively screens the presence of illicit drugs in the body.

Speed and Cost

Aside from accuracy, the main difference between a drug test and a drug screen is their speed and cost. Between the two, a drug screen is faster and more cost-efficient. A drug test, on the other hand, requires more time and analysis, making it a more expensive testing method.


A drug test is a meticulous examination used to detect the presence of commonly-abused drugs in the body. Since it is complex in nature, it is performed in laboratories that are equipped with testers and specialized apparatuses. Additionally, the analysis of specimen is conducted by experts in the field. Meanwhile, a drug screen, which is a simpler way to test specimen, can be performed at home with the use of an over-the-counter assay.


Another significant difference between the two is the screening apparatus used to monitor drugs. A drug screen requires a screening assay that tests the presence of substances in the urine and other biological matter. Unlike a drug screen, a drug test is performed with the use of sophisticated equipment used for gas chromatography and mass spectroscopy. This equipment is fully capable of monitoring and measuring the atomic weight, molecular charge, and molecular size of different types of drug metabolites. Since it provides in-depth data of metabolites, it is able to differentiate between tetrahydrocannabinol (THC) metabolites and ibuprofen, opiates and poppy seeds, and other types of drugs.

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