Frequently Asked Questions

Toxicology FAQ

Clinical Drug Testing is a lab test ordered by a healthcare professional to detect illegal or prescription drugs and/or their metabolites (breakdown products) in urine, blood, saliva, sweat, or hair samples in a clinical laboratory.

There are various reasons to perform drug testing. Clinical toxicology testing is performed for medical reasons, which often involves the following situations: 

  • Evaluating unexplained clinical symptoms possibly related to medications
  • Investigating unusual responses to medical treatment
  • Managing patients in chronic pain to minimize potential medical side effects
  • Monitoring medications with addictive properties
  • Determining substance use, misuse, or abuse

Many people require drug testing. Employment-related evaluations, patients with substance use disorders (SUDs) in treatment/recovery programs, legal/forensic matters concerned with substance use in relation to an incident, or high-level athletes may be subject to drug testing for the presence of substances. Patients on controlled medications are also tested to identify medication-use that is consistent or inconsistent with their prescriptions.

We provide both screening tests using chemistry analyzers and confirmation tests using LC-MS/MS. In our screening test menu, we test 17 drug classes plus 4 parameters for sample validity testing. In our confirmation test menu, we test 60+ drugs/substances organized into 30+ drug classes.

To make the ordering process easy, we provide convenient panels that cover the commonly-tested drugs. Moreover, we are able to customize tests and test panels according to patients’ and healthcare providers’ specific needs. We are aware that new medications and substances, especially synthetics, are constantly introduced to the public. For drugs that are not currently on our test menu, we will continue to update and make them available in the near future.

There are many variables that affect how long a drug/substance can stay detectable in your body:

  • Type of drug, amount/dosage, frequency, and route (oral, intravenous, intramuscular, sublingual, skin patch, etc.)
  • Body mass index (BMI: your weight in relation to your height) and basal metabolic rate (BMR: determined by your BMI, age, sex, and general level of daily physical activity)
  • The type of sample/specimen: blood, urine, saliva, sweat, hair, etc.

Generally, drugs will remain detectable for shorter durations if taken in smaller, less frequent doses, via less-absorbable routes (ie, skin patch) by younger, more metabolically-active individuals, and for samples that degrade more quickly (ie, body fluids, as opposed to hair).

The temperature strip measures the temperature of the sample collected in the cup. Freshly voided urine should fall between 90-100 degrees F with four minutes of sample collection; outside this range (too cool or too warm) is a red flag for possible sample tampering (adulteration, substitution, or other means to falsify anticipated results).

Depending on the drugs/substances in question, urine samples can stay valid for 4-7 days at room temperature after collection.

Screening tests will be reported as fast as the same day. Confirmation tests will be reported within 48 hours upon sample receiving.

Results are made available to the ordering healthcare providers through our Laboratory Information System (LIS) directly. Patients will obtain results from their healthcare providers.

Each methodology has its strengths. Having both is essential to a cutting-edge toxicology lab like ours. In short, screening provides fast and accurate results, but not to the extremely-high degree of accuracy and precision of confirmation testing, which demands more time to produce definitive results. For more details, please read on.

Screening tests are quickly done and are great for initial testing. These tests are reported as “positive” or “negative” (qualitative) if the substance is detected or not detected, respectively, which infers the use of the substance or not. Screening tests, though accurate, are uncommonly prone to “false positives,” an objective, positive test result that presumes use of a substance, when none occurred in reality. False positives typically occur due to “cross reactivity” of medications or other molecules with the substance in question. Generally, we advise reflexive confirmation testing for positive screens, especially in sensitive cases where positive results can be detrimental.

Confirmation testing is much more accurate than screening and is significantly less prone to false positives or false negatives, hence “confirmation.” Furthermore, numerical (quantitative) values are reported in the results with cutoff ranges. Positive confirmation tests reveal values at or above the cutoff threshold, while negative confirmation tests report values below the cutoff. These are more descriptive than the “positive” or “negative” (qualitative) screening reports. Confirmation testing requires more sophisticated instrumentation, and as such, processing is not as swift as it is with screening. However, since cross-reactivity is not an issue, the results are more definitive.

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