What are the steps of a drug test? A Comprehensive Guide to the Process

October 11, 2025 •

4 min read

According to a 2018 Quest Diagnostics analysis, positive drug tests in the American workforce reached their highest rate in a decade, highlighting the prevalence and importance of screening programs. Understanding what are the steps of a drug test is crucial, whether for pre-employment, a random screen, or medical monitoring. This process involves a meticulous series of procedures designed to ensure accuracy and integrity.

Quick Summary

This article outlines the typical multi-step process for drug testing, which includes sample collection under strict protocols, a two-phase laboratory analysis involving initial screening and definitive confirmation, and a thorough review by a Medical Review Officer. Different sample types like urine, hair, blood, and saliva are examined, along with the critical importance of maintaining a documented chain of custody throughout the entire procedure. The process is designed to prevent tampering and ensure reliable results for employment, legal, and medical purposes.

Key Points

Initial Screening: Most drug tests involve an initial immunoassay screening for rapid, cost-effective detection of presumptive drug use.
Confirmation Testing: Any non-negative screen must be verified with a highly accurate, lab-based confirmation test like GC-MS or LC-MS to minimize false positives.
Chain of Custody: A strict, documented chain of custody is maintained throughout the entire process to prevent tampering and ensure specimen integrity.
Medical Review Officer (MRO): All non-negative results are reviewed by an MRO, a licensed physician who verifies results and evaluates any legitimate medical explanations.
Sample Types: Different samples are used depending on the testing purpose, including urine for its broad detection window, blood for recent use, hair for long-term history, and saliva for recent impairment.
Reasonable Suspicion: In addition to pre-employment and random testing, some employers can conduct a drug test if they have reasonable suspicion of impairment.

Step 1: Preparation and Notification

Before any sample is collected, a preliminary phase of preparation and notification takes place. This varies depending on the purpose of the test, such as pre-employment, random screening, or post-incident testing. For pre-employment screening, a candidate is typically notified in writing that their job offer is conditional upon passing a drug test and must consent to the process. Federal regulations, like those for Department of Transportation (DOT) employees, mandate clear procedures.

Required Procedures During Preparation

Reviewing policies: The individual being tested should be informed about the company's or organization's drug-testing policy.
Providing consent: A consent form for testing must be signed, acknowledging the individual's understanding of the procedure.
Medication disclosure: The person should be prepared to disclose any prescription or over-the-counter medications that could potentially affect the results.
Documentation preparation: The collection site prepares the necessary paperwork, most importantly the Custody and Control Form (CCF) that will track the specimen.

Step 2: Specimen Collection and Chain of Custody

Collection is the most critical step for ensuring the integrity of the sample. The integrity of the process is maintained through a strict chain of custody, which is a documented paper or electronic trail proving who has handled the specimen from collection to final analysis.

The Collection Process

Identity verification: The collector, a trained professional, verifies the donor's identity using a photo ID.
Securing the area: The collection area (e.g., a restroom for urine tests) is secured to prevent tampering. This often includes turning off water taps, adding blue dye to the toilet water, and removing cleaning agents.
Direct observation (if required): For certain scenarios, such as a previous refusal to test or suspicion of tampering, the collection may be directly observed by a collector of the same gender.
Sample provision: The donor provides the sample in a sterile container provided by the collector.
Sealing and labeling: The collector measures the temperature of the sample immediately (for urine tests) and then divides it into two separate specimen bottles (A and B). These bottles are sealed and labeled in the donor's presence.
Form completion: Both the collector and the donor sign and date the CCF, documenting the transfer of the specimen.

Step 3: Laboratory Analysis

Once collected, the sample is sent to a certified laboratory for analysis. This process is typically divided into two key phases to ensure accuracy.

The Two-Phase Analysis Process

Initial screening (Immunoassay): The first test is a rapid, cost-effective immunoassay. This method uses antibodies to detect the presence of specific drugs or drug metabolites at a molecular level. Due to its high sensitivity, it can produce presumptive positive results but is not always specific enough to definitively identify a substance.
Confirmation testing (GC-MS/LC-MS): If the initial screen is positive, a portion of the sample is re-tested using a more advanced and specific method, most commonly Gas Chromatography-Mass Spectrometry (GC-MS) or Liquid Chromatography-Mass Spectrometry (LC-MS). These techniques provide a definitive confirmation of the specific substance and its concentration, minimizing the risk of a false positive. If the initial screen is negative, no further testing is needed.

Step 4: Medical Review Officer (MRO) Verification

Following the lab analysis, the results are sent to a Medical Review Officer (MRO), who is a licensed physician with expertise in substance abuse. The MRO's role is to review and interpret all results, particularly non-negative ones, before reporting them to the employer or requesting entity.

MRO Review Process

MRO receives results: The MRO receives the lab results and the CCF.
Contact with the donor (if needed): If the result is non-negative (positive, adulterated, or substituted), the MRO or their assistant contacts the donor. The MRO will confidentially ask about any prescribed medications or medical conditions that could explain the results.
Determination and reporting: Based on the information gathered, the MRO makes a final determination. If a legitimate medical explanation exists (e.g., a valid prescription), the test is reported as negative to the employer. If no valid explanation is provided, the test is reported as positive.

Comparison of Different Drug Test Types

Testing can be conducted on various biological samples, each with a different detection window and invasiveness.


Test Type	Sample	Detection Window	Pros	Cons
Urine	Urine	Days to several weeks, depending on the drug.	Most common and cost-effective.	Can be susceptible to tampering; shorter detection window for some drugs.
Blood	Blood	Hours to a couple of days.	Accurate for detecting recent use; can quantify levels.	Invasive; shorter detection window; more expensive.
Hair Follicle	Hair	Up to 90 days.	Longest detection window.	Cannot detect very recent use; more expensive; results can vary based on hair characteristics.
Saliva	Oral Fluid	12-24 hours.	Less invasive; quick to administer.	Shorter detection window; accuracy can be affected by recent use.

Conclusion

Navigating the process of a drug test involves a multi-layered procedure, beginning with proper preparation and notification. The integrity of the collection process is paramount and is ensured through the rigorous chain of custody protocol. This is followed by a two-step laboratory analysis that starts with a cost-effective screening and, if necessary, proceeds to a highly accurate confirmation test. Finally, the crucial review by a Medical Review Officer protects confidentiality and ensures fair and accurate interpretation of the results. Understanding these intricate steps provides clarity and confidence in the reliability and fairness of the overall drug testing procedure for all parties involved.

Drug Testing Information from the National Institute on Drug Abuse

Frequently Asked Questions

A chain of custody is a documented process that tracks the handling of a drug test specimen from the moment of collection until the results are reported. It ensures the integrity and security of the sample by recording every individual who handles it.

Yes, it is possible for some prescription or over-the-counter medications to cause a false positive result on an initial drug screen due to cross-reactivity. This is why a confirmation test and review by a Medical Review Officer are critical steps.

An MRO is a licensed physician who receives and reviews laboratory drug test results. Their role is to interpret the results, discuss any non-negative findings confidentially with the donor, and determine if there is a valid medical explanation before reporting to the employer.

A screening test (immunoassay) is an initial, rapid test designed to detect the presumptive presence of drugs. A confirmation test (GC-MS/LC-MS) is a more specific and accurate secondary test used to verify any positive screening results.

The detection window varies significantly depending on the drug, frequency of use, metabolism, hydration, and the type of sample being tested. For example, a urine test may detect marijuana for weeks, while a saliva test might only detect recent use.

If your test is non-negative, the MRO will contact you to discuss any potential legitimate medical reasons, such as a valid prescription. If you have a valid explanation and proof, the MRO can report the result as negative to the requesting entity.

Urine tests are the most common method due to their convenience, non-invasive nature, cost-effectiveness, and the fact that they can detect a wide range of drugs and their metabolites over a reasonable detection window.