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FAQs About Drug Test Results

If you have questions about your patient’s test results, DRUGSCAN’s expert toxicologists can assist you. DRUGSCAN prides itself as being a company committed to delivering a personal touch and a live voice on the phone to answer questions and provide support.

Is there anything that can be used to "cheat" a urine test?

There are two common ways that users attempt to "cheat" a urine drug test: modify their urine sample with chemicals drink large amounts of water prior to testing to dilute their sample Many products are available on the Internet that claim to enable a person to produce a negative test result after drug use if that product is added to a urine sample. Most of these products contain strong chemicals known as oxidants, which can modify the chemical structure of a drug.

How does DRUGSCAN detect “cheating” in a urine test?

DRUGSCAN performs thorough validity testing on every urine sample for the presence of oxidants to identify potential adulteration. DRUGSCAN can also detect diluted samples by measuring the concentration of creatinine in each sample. Individuals who consume large quantities of water prior to a test to dilute their sample will often have abnormally low levels of creatinine. Validation tests such as those described above are performed to identify individuals who are adulterating their urine specimen in this manner.

When should I send specimens to lab vs. using a POCT device?

Historically, “instant” urine drug testing has been used for pre-employment, workplace monitoring, and law enforcement applications. In these instances, results were used to verify that individuals are not under the influence or abusing drugs. Standard cut-off levels (normally as high as 300 or 2,000ng/mL for opiates) are adequate for detecting drug concentrations in their most basic form. However, standard cut-off levels are not effective in providing accurate assessments of patient compliance, or to monitor detox.

Medication monitoring and the most accurate drug testing requires much lower cut-off levels that can only be achieved at a lab. DRUGSCAN cut-off levels are designed to achieve 100% accuracy. POCT devices and analyzers are based on immunoassay technologies, which not only have elevated cut-offs but also are unable to identify specific drugs within a class.

DRUGSCAN uses the most advanced technology that provides a unique “chemical fingerprint” for the drug in question, enabling positive identification and quantitation at very low levels. Manufacturers’ instructions regarding POCT devices suggest subsequent quantification by a more specific method, such as LC/MS/MS. LC-MS/MS should be used when deemed medically necessary for the following reasons:

  • A more sensitive method is required allowing for better detection of individual drugs and metabolites
  • A more specific result is required that identifies both drug classes and specific drugs and metabolites within that class

Could a result be a false positive?

The concept of false positive is limited to immunoassay screening tests. DRUGSCAN reports results based on confirmation testing by GC/MS or LC/MS/MS. This type of testing provides what is effectively a “chemical fingerprint” pattern for each drug. DRUGSCAN advanced confirmation technology eliminates the possibility of false positives.

Why are POCT results sometimes positive for THC, but confirmation results negative?

Patients may be taking a prescription medication, such as Protonix, that is known to cross react with the cup and result in a THC positive. Also, THC metabolizes into several metabolites between which the cup cannot differentiate, meaning that the cup response is a cumulative result. Laboratory analysis detects only one of the many cross-reacting compounds, carboxy-THC, which may be at a concentration below the reporting limit.

My patient tests positive in the office for cocaine and marijuana, but claim they haven’t used these drugs. Is there a reason, other than use, that could cause a positive result?

This can happen when you rely solely on a POCT device or in office analyzer to determine results. Such devices recognize drug classes based on their “chemical shape” and most commonly change color when that shape is recognized. If other drugs with similar chemical shapes are present in the sample, this can result in a "false positive." Sustiva, Protonix, and other proton pump inhibitors can cause individuals to test positive for THC, while common antibiotics such as amoxicillin can cause a person to test positive for cocaine on certain POCT devices. DRUGSCAN uses advanced technology to confirm specific drugs and metabolites with 100% accuracy.

Why is codeine positive for a patient taking high levels of Morphine?

Morphine is not known to metabolize to codeine. Trace urinary codeine concentrations may be present in individuals on high doses of morphine due to codeine impurities in the morphine tablet. The presence of this codeine impurity is well documented and can account for low concentrations of codeine detected in the urine from patients who have been prescribed relatively high doses of morphine for extended periods of time. When the morphine concentration is low, this trace codeine impurity is undetectable; however, at high morphine concentrations, codeine may increase slightly above the minimum detection limit. That is why detection levels must not be too high or too low and set at just the right level to make a good decision.

Why are their urine levels different for patients taking the same dose of Hydrocodone?

There are many variables associated with urine drug levels. Caution should be used when interpreting quantitative levels. A few common reasons for the differences in urine levels for two patients on the same dose of drug include urine pH, co-administration of other drugs, hydration level, cardiac output, timing between dose and specimen collection, and possibly patient non-compliance. While DRUGSCAN confirmation testing can accurately detect specific medications, drugs, and metabolites and demonstrate recent use; it is very difficult to correlate urine drug concentration with a patient’s dose because of the criteria listed above.

My patient missed their dose of oxycodone last night, should I expect a negative test result?

That depends on a combination of factors including: dose, frequency of dose, and metabolism/excretion capabilities. If the patient is prescribed oxycodone TID or QID then the urine should still test positive for the drug. If the patient is only prescribed single daily doses and they are capable of rapid metabolism/excretion, then the result may be negative due to screening cut-offs. The patient may also test positive for oxymorphone only as the detection window in the urine for this metabolite is longer than the parent drug.

The levels of oxymorphone are higher than oxycodone. Is my patient abusing Opana?

Not necessarily. Clinical trials indicate that the ratio of oxymorphone to oxycodone can vary from 0-184 percent and that there is no direct correlation between the dose and the resulting ratio. The detection window for oxymorphone is slightly longer than oxycodone. This means oxymorphone may still be detectable even though oxycodone has been completely eliminated from the body.

My patient takes Adderall and tested positive for methamphetamine and amphetamine. Is that due to their Adderall prescription?

Adderall does not contain methamphetamine. The use of Adderall can cause a patient to test positive for amphetamine but not methamphetamine. Amphetamine does not metabolize to methamphetamine.

I am prescribing methadone and the result is positive for both methadone and EDDP. Is my patient taking the medication as prescribed?

Concentrations of methadone and its metabolite, EDDP, vary widely and depend on many factors such as metabolism/excretion rates, dose and dose frequency, and urine pH. Compliance cannot be determined solely from urinary methadone/metabolite concentrations.

If my patient tests negative for benzodiazepines even though I prescribed a low dose, does that mean they are not taking them?

It is possible. Low doses of benzodiazepines (especially alprazolam and lorazepam) can be reported negative during a screen. For this reason, DRUGSCAN uses direct assay for all opiates and benzodiazepines and drugs in this class skip screens with higher cut-offs to avoid false negative results.

Could the low level of morphine on a report be from something the patient ate?

At DRUGSCAN, our toxicologists have the experience to determine if results detect morphine or codeine resulting from poppy seed ingestion, which applies only when the patient is not prescribed morphine or codeine.

Does phentermine cause a positive result for amphetamines?

No. Phentermine (Adipex) is distinguished from amphetamine and methamphetamine during DRUGSCAN confirmation testing. Mass spectrometry provides a chemical fingerprint for phentermine, which is independent of those obtained for amphetamine and methamphetamine.

How do urine alcohol levels compare to blood alcohol levels?

Ethanol (drinking alcohol) may be detected in blood and urine after consumption of alcoholic beverages. Blood and urine ethanol concentrations may be very different, depending on the time between ethanol consumption and specimen collection and frequency of urination. The ethanol concentration will often be higher in urine than in blood. In some cases, urine ethanol may be highly positive and the blood completely negative.