Role of the medical review officer
In workplace drug testing, the outcome of a positive result may be that an individual’s employ ment contract is terminated or that they are not offered employment. These are critical decisions and the person making these decisions needs to be qualified to do so for their judgement to be considered acceptable. It is debatable whether the laboratory carrying out the testing has personnel suitably qualified to interpret the results in the full medical context and to make decisions based on the outcome of the tests. The medical history of the individual may be important in the context of interpreting the results and there may also be issues regarding bias of the test laboratory if a dispute arises over the results. Hence it is considered good practice in many jurisdictions for someone not associated with the test laboratory to make decisions whether a result is positive or not. In the USA, this role is carried out by an MRO.
The concept of MRO was introduced in the HHS Guidelines. Their initial role was to receive the testing results from the laboratory, contact the donor to determine whether a positive drug result could have arisen from the legal use of a drug and, if not, to verify the result as positive and contact the employer. Where the legal use of a medication explained the result, the MRO would report the result as negative and communicate this to the employer.
Increasingly, MROs serve as gatekeepers for drug-testing results and as administrators of functions ancillary to the process, such as the collection and storage of all documentation. Given the breadth of these tasks and the extent of drug testing in the USA, some physicians practice full time as MROs. Many others act as MROs in the course of their duties as occupational health physicians and corporate medical directors. Before the introduction of the federal programmes, the laboratory toxicologists had filled the interpretative role, and few issues had arisen. However, within the federal programmes, which introduced random and post-accident testing to a large percentage of the workforce, there was a need for additional safeguards. It was anticipated that MROs would serve as the final quality-assurance check on the laboratory result and, indeed, they have done so. For example, some vigilant MROs who could not rationalise the laboratory result with the donor’s demo graphics and medical history first raised the phenomenon of the conversion of ephedrine and pseudoephedrine to methamfetamine. They questioned the findings and requested the re tests in which the second laboratory could not confirm the findings. Another reason for their introduction was a purely legal one; in the USA only, licensed physicians can access prescription records, and it was obvious that this could be essential to determine the legitimacy of a donor’s claim. When the MRO receives a positive result, he or she has to contact and interview the donor, obtain prescription records (if necessary) and then verify the laboratory result as positive or negative before reporting the result to the employer. These reviews are generally straight forward; for example, there is no legal reason for a donor to test positive for PCP, whereas a large majority of specimens that test positive for codeine do so because of prescription use or, in countries such as the UK, as a result of the extensive use of codeine in over-the-counter medicines. In other areas questions arise, particularly in the interpretation of methamfetamine and morphine positives.
The MRO is also responsible for reviewing non-negative results from donors. These include adulterated, substituted and invalid specimens. Before 2000 when the new regulation was issued (Federal Register 2000), MROs had very little role in the review of substituted and adulterated specimens; they simply received the results from the laboratory, reviewed the paperwork and reported them to the employer. There was no requirement to contact the donor and no ability for the donor to request a re-test. The new regulations changed that and incorporated a require ment for the MRO to contact the donor to determine whether there was a medical reason for the laboratory findings, although this would be extremely unlikely, and allowed the donor to request a re-test. These particular re-tests were to be performed using the same criteria for defining a specimen as substituted or adulterated as used in the initial set of tests. For example, if a specimen was determined to be substituted, with creatinine readings of 4.8 and 4.7 mg/dL and with relative density readings of 1.001 on bottle A while bottle B had a creatinine reading of 5.1 mg/dL and a relative density of 1.001, the re-test specimen would be reported as ‘Failed to Confirm: Substituted Specimen
