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Most urine drug testing simply determines the absence or presence of a drug. The Ameritox Rx GuardianSM process with Rx Guardian CDSM is the only urine drug monitoring solution that uses a proprietary normalization algorithm and compares patient normalized results to a reference database of chronic pain patients who were clinically assessed as adherent. Comparing patient results against results in this database gives clinicians added assurance in assessing whether patients are taking their medications correctly.

Contact Ameritox to learn more about the Rx Guardian process.

The Rx Guardian Process features Rx Guardian CDSM and results in the Rx Guardian Results ReportSM, a comprehensive report that gives you insight to help you assess your patients’ pain medication adherence. This process includes:


Specimen Validity Testing

Once a urine specimen is received in one of our labs, it is scanned into the system and receives a unique lab accession number for the most reliable identification and tracking. Then an alliquoted sample undergoes validity testing (as a part of Initial Testing) using pH values, specific gravity and creatinine to ensure it is a human sample and that it has not been diluted or adulterated.

Initial Screening

An initial Enzyme Immunoassay (EIA) test screens for the presence of opiates, benzodiazepines, illicits and other prescribed or non-prescribed medications. The EIA uses antigen antibody reactions to provide fast, reliable results.

Confirmation Testing

If positive, immunoassay is followed by confirmation testing through one of the following methods:

  • Gas chromatography-mass spectrometry (GC/MS) is used to create a fingerprint-like match for each detected prescription medication or illicit. This technology’s superior sensitivity can detect drugs or metabolites at some of the lowest levels in the industry.
  • Liquid chromatography – tandem mass spectrometry (LC/MS/MS) is used when optimal specificity and sensitivity are required to detect the absence or presence of your patients’ prescribed medications as well as the presence of non-prescribed medications or illicits.

The methodology to obtain confirmation depends on the type of drug being tested.

Rx Guardian CDSM– Reference database supported by a proprietary algorithm

Once a specimen has undergone laboratory testing the results are certified by our Ameritox Certifying Scientists. We then apply our proprietary normalization algorithm to the test results as part of Rx Guardian CDSM.

  • Rx Guardian CDSM is the most comprehensive reference database of pain patients clinically assessed as adherent, supported by a proprietary normalization algorithm.
  • Our proprietary database and process are derived from more than one thousand actual chronic pain patients.
  • A rigorous assessment protocol identifies patients who are likely adherent to their chronic opioid therapy.
  • The Rx GuardianSM proprietary algorithm adjusts drug levels for certain physiologic variables, generating a normalized drug value.
  • These normalized values populate the Rx Guardian CDSM reference database.
  • Your patients’ results can be compared against this dynamic database of patients to help you assess whether your patients are taking their medication correctly.

Rx Guardian Results Report

Results are delivered in a comprehensive Rx GuardianSM results report, which includes your patient’s normalized value and compares it to the Rx Guardian CDSM reference database. See a sample Rx GuardianSM results report and learn how to interpret the results.

When interpreting patient results:

  • Less than 5 percent of patients clinically assessed as adherent in the Rx Guardian CDSM database have standard scores less than -2 or greater than +2.
  • Less than 1 percent of patients clinically assessed as adherent in the Rx Guardian CDSM database have standard scores less than -3 or greater than +3.
  • Patients whose normalized drug values exceed two standard scores from the reference database mean, accompanied by clinical indicators of risk (such as aberrant behaviors), may have a higher likelihood of drug abuse, misuse, or diversion.
  • Patients whose normalized drug values fall within two standard scores from the mean of the index database, and who lack clinical indicators of risk (such as aberrant behaviors), may have a lower likelihood of drug abuse, misuse, or diversion.

The Rx GuardianSM results report also provides helpful results explanations of any findings that are inconsistent with the prescribed medication treatment plan. If you have questions, Ameritox Toxicology SpecialistsSM are available to help you interpret results. It all adds up to unique insight that only Ameritox can provide—insight that is informing thousands of chronic pain treatment conversations every day.

Contact Ameritox today to learn more about pain medication monitoring solutions or to make the Rx GuardianSM Process a part of your practice.

1. Katz N, Fanciullo GJ. Role of urine toxicology testing in the management of chronic opioid therapy. Clin J Pain. 2002;18(4 suppl):S76–S82.

2. Bhamb B, Brown D, Hariharan J, Anderson J, Balousek S, Fleming MF. Survey of select practice behaviors by primary care physicians on the use of opioids for chronic pain. Curr Med Res Opin. 2006;22(9):1859–1865.