Most workplace drug-testing programs include tests for the 6 types of drugs mandated in the DHHS guidelines and the DOT regulations: marijuana metabolites, cocaine metabolites, amphetamine, opiate metabolizes, and phencyclidine POP).
This drug-testing panel is referred to hereafter as the THC 6 drug panel. The NRC regulations allow testing of individuals for additional drugs under specific circumstances, usually, e.g., barbiturates, benzodiazepines, and methadone. Testing for alcohol by evidential breath devices is required by DOT and NRC rules, but these test results are not subject to MRO review and will only be mentioned briefly later in this chapter. Employers that are subject to DOT regulations are only allowed to test employees for the HHS 5 drug panel under the DOT rule. However, they may test their employees for extra drugs under their own authority; provided the additional tests are performed on a separate specimen from the one used for federally required testing. The added specimen must be obtained from the donor in a separate collection (it cannot be Poured off” from the urine specimen being used for the federal drug test) and it must be submitted to the laboratory on a separate custody and control form. The federal custody and control form (CCF) cannot be used for these purposes. The MRO should be aware that if testing is being performed by a laboratory for drugs not included HHS panel, laboratory work pertaining to those tests is not subject to proficiency testing or inspection by the DHHS.
Many changes to the DOT regulations came about in 2001 with the publication of the revised CFR Para 40. New and revised DHHS guidelines have also been issued in the last 10 years that directly involve the MRO function. Examples of such changes in Part 40 are the requirement that a split specimen be collected for all DOT drug testing, the definition and requirements for Specimen Validity Testing and the explanation and requirements for handling of dilute urine specimens
The review and understanding of nonnegative laboratory test results remains the central function of the MRO in workplace drug-testing programs. Nonnegative results include those reported by the laboratory as positive for a drug or drug metabolite, substituted Specimen not consistent with human urine), adulterated (something added to the specimens, or invalid (unable to obtain a valid test result). For all the non-negative results, the MRO must conduct an interview Telephone or in-person} with the specimen donor to determine if there is a legitimate medical explanation for the laboratory finding). This interview is conducted before the laboratory results are reported to the employer. In federally mandated testing, the MRO must review a copy of the CCF, ensuring that it has been signed by the specimen donor, and appropriately documents the security, recognition, and reliability of the specimen and the test result. The MRO also receives and reviews a written report from the laboratory, including a copy of the CCF signed by the laboratory’s certifying scientist. The interview with the specimen donor must be conducted by the physician MRC, not a staff member, and should be initiated as soon as practical (within 24 h or next business day) after receipt of the laboratory results. If, during the interview, the donor presents a legal medical explanation for the test result, the MRO must authenticate the medical record or medication information offered, and maintains the documentation as part of the case record. The donor does not provide acceptable documentation of a lawful medical explanation for the laboratory result, the confirmed positive test is verified as positive; the adulterated or substituted specimen is verified as a refusal to test, and the invalid result is canceled, with a requirement for the donor to submit to another specimen collection under direct observation. The interpretation and MRO verification of test results is explained in more detail later in this chapter. The current DHHS/DOT laboratory screening and cutoff concentrations are summarized in Table 1.1.
Table 15-1 Cutoff Concentrations for initial and Confirmation Tests