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A guide to NIDA certification for workplace drug testing.

Federal approval opens a large market for laboratories that meet stringent requirements, including a hefty annual fee for PT.

Battles against the use of illicit drugs in the United States continue on many fronts. One example is the increasing number of employers that screen applicants and employees for drug use. Such companies wish to reduce poor employment risks and minimize workplace accidents while assuring that employees in sensitive positions, including those whose actions may affect public safety, are unimpaired. Ever aware of public opinion, these firms also want to project a positive corporate image by supporting the national anti-drug campaign.

Workplace drug testing programs represent a major new market for strategic planners in clinical laboratories.[1] Such screening gained national attention in 1986 when President Reagan issued an executive order requiring air traffic controllers and other Federal employees in sensitive positions to be tested. President Bush has fully supported the program with the aim of creating a drug-free Federal workplace. The program has been extended to include the employees of private firms holding Government contracts of $25,000 or more.

Critics observed that drug testing, no panacea for the nation's drug problem, is fraught with technical difficulties and civil liberties issues.[2-4] It was prudent for the Government to address these objections before implementing the first directive.

* Accuracy is key. Studies indicate that some labs have unacceptably high false-positive and false-negative rates.[5,6] Other studies suggest that labs with competent, experienced staffs routinely produce reliable, valid test results.[7,8]

A positive drug test has a number of administrative and legal consequences. The Department of Health and Human Services (HHS) needed to find a way to insure unimpeachable laboratory performance. The solution was to provide specific guidelines for participating laboratories as well as a mechanism for certifying them.

The department's National Institute on Drug Abuse (NIDA), created in 1974, is the leading Federal agency for the research and monitoring of drug abuse in the U.S. NIDA created the Office of Workplace Initiatives in support of the 1986 executive order. From that office came the Mandatory Guidelines for Federal Workplace Drug Testing Programs, in effect since April 11, 1988, and the National Laboratory Certification Program (NLCP),[9] which will be discussed in this article.

While any clinical laboratory can test for drugs of abuse, not many meet the requirements of a large-volume forensic testing laboratory as delineated in the 1988 guidelines.[10] A clinical laboratory performs drug testing for medical reasons in support of patient care. A forensic laboratory tests for legal reasons, with results intended for use as evidence in a court of law. Any laboratory that seeks NIDA certification must become a forensic laboratory.

* Certification. All Federal agencies except the armed forces, the postal service, and the executive and legislative branches are subject to the guidelines. Only laboratories certified by NIDA may test for Federal agencies. A lab need not be certified to perform testing for any non-Federal organization or private company. Because NIDA guidelines have become the benchmark for workplace drug testing, however, many firms prefer to contract with certified labs. Although Federal agency testing may represent only a fraction of a lab's workload, winning the certification required to engage in it may well attract many non-Government accounts.

The full certification process is summarized in Figure I. The NLCP consists of two components: a proficiency testing program and onsite inspections.

* Proficiency testing. Once it has accepted a laboratory's detailed application, NIDA enrolls the lab in the NLCP proficiency testing program. An annual fee of $17,000 defrays the cost of administering this sophisticated program. Naturally, the expense also gives labs cause to stop and consider just how serious they are about desiring NIDA certification. Moreover, enrollment in the program and payment of the fee do not guarantee that certification will be granted. * Performance testing. Each laboratory under consideration must pass three initial performance testing cycles. Proficiency sets consist of drug-free urine and other specimens containing one or two drug analytes at various concentrations. The submissions are processed and analyzed as if they were actual specimens sent for testing. The initial cycles of testing are typically completed in about three months. To pass, a laboratory must meet five requirements:

1. Report no false positives. Failure means automatic elimination.

2. Correctly identify and confirm 90% of the tested drug analytes in each cycle.

3. Report quantitative gas chromatography/mass spectrometry (GC/MS) results within [+ or -] 20% (or [+ or -] 2 SD) of the reference values for at least 80% of the challenges.

4. Report no quantitative GC/MS values that differ by more than 50% from reference values.

5. Acceptably detect and quantitate at least 50% of all challenges for any individual drug.

Certification requires passing the initial three proficiency testing cycles. Thereafter, the laboratory must analyze equally tough proficiency sets every two months. Failure to pass PT at any time may result in suspension or revocation of certification, actions that can also follow refusal to participate in the PT program.

* Inspection. Inspections are similarly ongoing. A three-member team visits each certified laboratory twice a year. During the inspection, each team member derives a complete and independent finding. A consensus report is then prepared from the inspectors' observations. That document forms the basis of NIDA's recommendation, made to the Secretary of HHS, to grant or deny certification.

Holding each inspection over a span of two days permits operations on all shifts to be examined. A typical inspector is qualified to be a forensic laboratory director, has undergone NIDA-sponsored inspector training, and carries a detailed inspection checklist covering all major points of the guidelines. The list includes drugs screened and their cutoff values, personnel requirements, standard operating procedures, physical security, chain-of-custody protocol, and screening, confirmation, and reporting procedures.

* The NIDA five. All approved labs must be able to screen and confirm the "NIDA five": amphetamines, including methamphetamine; cocaine (benzoylecgonine); marijuana (THC); opiates (codeine and morphine); and phencyclidine (PCP). Mandatory screening and confirmation cutoffs for these drugs are shown in Table I.
Table I
NIDA screening and
confirmation cutoff levels
Drug (ng/ml)
Immunoassay screening
THC (metabolites) 100
Cocaine (metabolites) 300
Opiates (metabolites) 300
PCP 25
Amphetamines 1,000
GC/MS confirmatory testing
THC ([Delta]-9-THC-9-carboxylic
 acid) 15
Cocaine (benzoylecgonine) 150
 Morphine 300
 Codeine 300
PCP 25
 Amphetamine 500
 Methamphetamine 500

NIDA retains the right to change cutoffs in response to improved analytical technology or other considerations. To date, NIDA has not altered its original cutoff levels, which were chosen to minimize the chance of false positives. The legal implications of false positives demand a conservative approach.

NIDA seeks to detect illegal drug users/abusers while protecting individuals who have legitimately or accidentally ingested a controlled substance. A person testing positive for codeine may have received a prescription for a non-aspirin painkiller with codeine from a physician, for example; a person testing positive for marijuana may have inhaled it passively.

Federal agencies (and, consequently, NIDA laboratories) may test for other drugs included in Schedule I or II of the Controlled Substances Act. Private companies often screen for barbiturates, benzodiazepines (e.g., Valium), methaqualone (Quaalude), or methadone. Firms often specify cutoffs that are lower than NIDA's, such as 20 ng/ml for THC instead of NIDA's 100 ng/ml cutoff. Labs can perform both Federal and other work as long as the former meets all NIDA specifications.

* Personnel. NIDA inspectors scrutinize personnel files to make sure the agency's explicit requirements have been met. Among them are two job categories:

[paragraph] The lab must be directed by a responsible person, known by the Federal designation RP. A full-time employee responsible for all aspects of testing, the RP must be state certified as a forensic or clinical laboratory director or must possess a Ph.D. in an appropriate discipline or possess the equivalent training and experience.

[paragraph] Laboratory certifying scientist (LCS). A title peculiar to forensic labs, the LCS reviews all paperwork that pertains to the testing. The RP may also be an LCS.

* Manual. Each NIDA-certified lab must write a comprehensive manual of standard operating procedures (SOP) that covers all aspects of testing, including technical and clerical. The NIDA inspection checklist serves as the basis for an SOP manual. Copies of the manual must be available in all sections of the forensic laboratory. Much of each inspection is devoted to making sure procedures are carried out as written.

* Security. One essential feature of the forensic lab is adequate physical security. Cipher or key card locks admit only certified personnel or persons they are escorting. The comings and goings of visitors must be noted in a log book.

Procedures performed in a certified laboratory must be able to withstand forensic scrutiny in a court of law. Consequently, NIDA places great importance on chain-of-custody (COC) procedures. A small operation with limited staff who perform multiple tasks may meet COC requirements more easily than a large lab. For the latter, an additional layer of internal security may be needed so that work spaces for specimen accessioning and testing can be kept apart, with access restricted to each group. In a large forensic laboratory, where security is harder to maintain, supervisors are the only employees who should have unrestricted access to all functional areas.

* Evidence. The legal implications of drug testing are well known to the inspectors, who check specimen accessioning and the identity and security of the original container. The specimen bottle should always remain in a secure accessioning area. Intake personnel pour aliquots, which are then given to analytical laboratorians for screening and confirmatory testing. Every aliquot must be accounted for on an internal COC document.

* Testing procedure. Each initial test is an immunoassay screening procedure that uses a specific number and type of calibrators, controls (both open and blind), and other quality control materials. Test results that are below the immunoassay cutoffs are reported as negative. Results at the cutoff levels or above require confirmatory testing.

Confirmation is by GC/MS, again with rigidly specified controls. Specimens at or above the cutoff are considered positive. A positive result is reported only if it equals or exceeds the cutoff value for both screening and confirmation.

Screening assays detect many drug metabolites, any of which may contribute to the analytical signal. Because GC/MS is specific for one metabolite, it is possible for a specimen to be well above the screening cutoff yet fail to be confirmed by GC/MS.

Inspectors review details of testing that affect either the technical quality of the results or their forensic defensibility. SOPs and records pertaining to reagents, equipment, and quality control are closely examined. Some checklist items are familiar to clinical laboratorians: pipet calibrations, glassware washing procedures, and the practice of checking new reagent lots by parallel testing with the current batch before introducing the material. Transcending routine clinical practice are such procedures as verifying the identity, purity, and concentration of drug reference materials by GC/MS analysis.

* Reporting. Inspectors scrutinize the reporting procedures to assure that patient confidentiality is maintained. To protect workers, NIDA requires that employers report all positive results to a medical review officer (MRO). The MRO, a physician who works for the employer, seeks a legitimate medical explanation for positive results. The physician interviews the worker and interprets the test finding in light of a medical history, seeking a logical and acceptable explanation other than intentional use of an illicit drug.

* |Fatals.' Certain items on NIDA's checklist are known as "fatals" because failing any of them endangers a laboratory's chances of becoming certified. If the problem is easily corrected and a solution documented, certification will probably not be denied. For example, positive specimens must be stored frozen for at least a year in a secure (locked) freezer. If the storage conditions fulfill all other requirements, simply placing a padlock on the freezer may correct a "fatal."

* Granting certification. While NIDA inspectors heavily influence the certification process, they do not determine which labs are certified. It is the secretary of HHS who grants, revokes, or suspends certification. The decision is based on the recommendation of NIDA, which relies on the objective performance of the laboratory in the PT program as well as the comments of inspection teams.

Any laboratory manager interested in investigating the possibility of working toward NIDA certification should obtain a copy of the guidelines from the Federal Register and guidance directly from NIDA. Information is available from the Drug-Free Workplace Helpline, at (800) 843-4971, and from the National Institute on Drug Abuse, Workplace Performance and Technical Research Branch, 5600 Fishers Lane, Rockville, MD 20857.

To date, approximately 75 laboratories have been certified by NIDA through NLCP; many more were pursuing certification at press time. Certification presents a significant challenge for laboratories as well as an attractive opportunity for their development.

[1]De Cresce, R., and Lifshitz, M. Drug abuse screening: Get your lab's share of a booming market. MLO 19(10): 31-34, October 1987. [2]Lundberg, G. Mandatory unindicated urine drug screening: Still chemical McCarthyism. JAMA 256: 3003-3005, 1986. [3]McCunney, R. Drug testing: Technical complications of a complex social issue. Am. J. Ind. Med. 15: 589-600, 1989. [4]McBay, A., and Hudson, P. Cost-effective drug testing. J. Forensic Sci. 32: 575-579, 1987. [5]Hanse, H.; Caudill, S.; and Boone, D. Crisis in drug testing: Results of CDC blind study. JAMA 253: 2382-2387, 1985. [6]Davis, K.; Hawks, R.; and Blanke, R. Assessment of laboratory quality in urine drug testing. JAMA 260: 1749-1754, 1988. [7]Frings, C.; White, R.; and Battaglia, D. Status of drugs-of-abuse testing in urine: An AACC study. Clin. Chem. 33: 1683-1686, 1987. [8]Frings, C.; Battaglia D.; and White, R. Status of drugs-of-abuse testing in urine under blind conditions: An AACC study. Clin. Chem. 35: 891-894, 1989. [9]Mandatory guidelines for Federal workplace drug testing programs. Federal Register 53: 11970-11989, April 11, 1988. [10]Crouch, D., and Wilkins, D. Managing the transition to a certified toxicology lab. MLO 23(9): 58-60, September 1991.

David A. Armbruster, Ph.D., DABCC is chief of analytical sciences at the Drug Testing Laboratory, Brooks Air Force Base, San Antonio, Tex., and an inspector for NIDA's National Laboratory Certification Program. The views expressed in this article do not necessarily reflect those of the Air Force or the Department of Defense.
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Title Annotation:National Institute on Drug Abuse
Author:Armbruster, David A.
Publication:Medical Laboratory Observer
Date:Feb 1, 1992
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