What is the Medical Review Officer (MRO) action if a drug test is reported as adulterated due to excessively high nitrite levels?

From the Guidelines

When a drug test is reported as adulterated with nitrite levels too high, the Medical Review Officer (MRO) must report this as a "Refusal to Test." The MRO should first contact the donor to discuss the finding and provide them an opportunity to explain the adulteration. However, there is no legitimate medical explanation for elevated nitrite levels in urine specimens above the cutoff (generally >500 mcg/mL) 1. The MRO should inform the donor that chemical adulterants containing nitrites are sometimes used to mask drug use by interfering with drug testing methodologies. During this discussion, the MRO should document the conversation thoroughly, including any explanation offered by the donor. After this process, the MRO must report the final determination as a "Refusal to Test" to the employer or designated representative, which carries the same consequences as a positive drug test result. This determination is made because specimen adulteration represents an attempt to subvert the testing process, compromising the integrity of the drug testing program. The employer typically follows their established policy for handling such cases, which often includes removal from safety-sensitive duties and potential disciplinary action. Some key points to consider in this process include:

• The importance of documenting all conversations with the donor thoroughly 1
• The need to follow established policies for handling cases of specimen adulteration
• The potential consequences of a "Refusal to Test" determination, which can be significant for the donor. It's also important to note that interpreting drug test results can be complex, even for experienced clinicians, and should be done with caution 1. Seeking assistance from the testing laboratory is important, particularly when test results do not correlate with clinical findings and when a physician suspects the use of a particular substance that is not included in a test panel.

From the Research

Medical Review Officer (MRO) Action for Adulterated Drug Test

If a drug test is reported as adulterated due to excessively high nitrite levels, the Medical Review Officer (MRO) will take the following actions:

• The MRO will review the test results and the laboratory's documentation to determine if the nitrite levels are consistent with adulteration 2.
• The MRO will consider the possibility that the nitrite levels may be due to natural sources, such as certain medications or medical conditions, and will review the donor's medical history and any relevant documentation 2.
• If the MRO determines that the nitrite levels are consistent with adulteration, the test result will be reported as adulterated and the donor may be subject to further testing or disciplinary action 3, 4.
• The MRO may also consider the use of alternative testing methods, such as gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-mass spectrometry (LC-MS), to detect the presence of drugs or their metabolites in the urine specimen 5, 6.
• In some cases, the MRO may request additional information or testing to confirm the presence of adulterants or to rule out other explanations for the abnormal test results 5, 6.

Detection of Nitrite Adulteration

Nitrite adulteration can be detected using various methods, including:

• Spectrophotometric methods to measure nitrite concentrations in urine 2.
• Rapid spot tests using hydrogen peroxide or potassium permanganate to detect the presence of nitrite or other adulterants 3.
• On-site adulterant detection devices that test for creatinine, nitrite, pH, specific gravity, and other parameters 5.
• LC-MS or GC-MS confirmatory techniques to detect the presence of drugs or their metabolites in the urine specimen 6.

Markers for Nitrite Adulteration

Research has identified certain markers that can be used to detect nitrite adulteration, including:

• 2-nitro-morphine and 2-nitro-morphine-6-glucuronide, which are stable reaction products formed when morphine and morphine-6-glucuronide are exposed to nitrite 6.
• These markers can be detected using LC-MS or GC-MS confirmatory techniques and can be used to indirectly monitor the presence of morphine and morphine-6-glucuronide in urine specimens adulterated with nitrite 6.