Drug testing is an important part of many organizations, and employers must choose between two primary methods: lab-based and rapid drug . According to a recent study by the Substance Abuse and Mental Health Services Administration (SAMHSA), the vast majority of drug tests are conducted using urine samples (88.9%). But how do the accuracy and reliability of lab-based and instant tests compare? And what about the cost and turnaround time?

Read: Why Choose a SAMHSA-Certified Lab?

Laboratory Drug Tests

Methodology

Laboratory drug tests, often referred to as confirmatory tests, are typically conducted in certified laboratories using sophisticated techniques like Gas Chromatography-Mass Spectrometry (GC-MS) or High-Performance Liquid Chromatography (HPLC). These methods involve a series of steps including sample collection, preparation, separation, detection, and data analysis.

Rapid Drug Tests

Methodology

Rapid drug tests, also known as point-of-care tests, use immunoassay techniques to provide quick results. These tests typically involve the use of test strips or kits that change color in the presence of specific drugs. They are designed for ease of use and require minimal training.

Difference between lab drug test and instant drug test

Collection Method

Lab-based tests usually require a urine, hair, or blood sample, which is then sent to a laboratory for analysis. On the other hand, instant tests are done on-site and typically use a saliva or urine sample.

Accuracy and Sensitivity

While rapid tests are generally accurate, they are less precise compared to laboratory tests. They have higher rates of false positives and false negatives. In such cases, confirmatory lab testing is recommended. Rapid tests may not detect very low levels of drugs and are limited in their ability to distinguish between different substances. They are often designed to detect common drugs of abuse such as marijuana, cocaine, opiates, amphetamines, and benzodiazepine.

Read: How to interpret drug test results?

Processing Time

Rapid tests provide results within minutes, making them suitable for on-the-spot testing situations where immediate results are necessary, while laboratory tests require anywhere from a few days to a week for result analysis.

Detection Window

Lab tests are generally more sensitive and can detect drug use over a longer period (up to 90 days) than instant testing, which may only detect drug use within the past few days.

Suggested: What are the Standard Cut-Off Levels of Drug Tests?

Cost

Rapid drug screen tests are generally less expensive than lab-based tests and are often used in settings where budget constraints are a consideration, which require laboratory analysis and may also incur additional costs for sample collection and transportation.

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Legality

Lab tests especially SAMHSA-certified lab tests, may be required by federal laws or regulations for safety-sensitive workplaces as those mandated by the Department of Transportation for CDL drivers, while rapid testing may not be legally admissible in certain situations yet depend solely upon employer’s drug testing policy.

Chain-of-custody procedures

Maintaining a strict chain of custody is crucial for the legal admissibility of drug test results. Lab-based tests often have more strong chain of custody procedures in place.

Common Drug Testing Scenarios

• Pre-employment Screening: A combination of rapid and lab-based tests can be effective. Rapid tests can be used for initial screening, and positive results can be confirmed with a lab-based test. For safety regulated positions only SAMHSA certified lab results are acceptable.
• Random Drug Testing: For safety sensitive jobs, as per mandated by FMCSA, only laboratory drug screening is used as it strictly follows the DOT guidelines and procedures.
• Post-Accident Testing: Lab drug screening are generally preferred for post-accident testing to provide accurate and comprehensive results.
• Rehabilitation Monitoring: Lab-based tests are often used for long-term drug monitoring programs to track sobriety and detect relapses.

Striking the Right Balance

The best drug testing solution depends on your specific needs and circumstances. For example:

• If you need to quickly screen job applicants, a rapid test might be sufficient.
• For safety-sensitive positions or legal compliance, a lab drug screening is often necessary.
• False positives from rapid tests may necessitate lab drug test confirmation.