Drug Testing Toxicology
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· Detecting opiates |
Detecting opiates with TesTcup and the Opiate 2000 cutoff change
Stuart C. Bogema, Ph.D., DABFT Forensic Testing, Inc.
The primary purpose of the opiate test has been to detect morphine and codeine. These are naturally occurring narcotics found in the poppy plant. Both are the central nervous system depressants that relieve pain and are addictive. Both continue to be important medicine, morphine primarily as an injectable analgesic and codeine in Tylenol #3 with acetaminophen as an oral pain reliever and as a cough suppressant. Morphine is also a metabolite of codeine. A metabolite of a drug is formed in the body, primarily the liver, by enzymes which slightly change the chemical structure of the drug to make the metabolite.
Morphine can be made into heroin (diacetylmorphine) by the addition of two acetyl groups. Heroin is made in labs in Mexico, Columbia, and Asia and smuggled into the United States. After injection, smoking, or snorting, heroin is quickly metabolized in the body to 6-acetylmorphine by the removal of one acetyl group and, then, morphine after the removal of the second acetyl group. The consumption of poppy seeds can cause morphine and/or codeine to be detected in urine. This is because the seeds of the poppy plant also contain the naturally occurring morphine and codeine.
The screening tests for drugs are called immunoassays. These tests use antibodies that are produced in animals or cell cultures as part of the immune system. These antibodies are made to specifically bind to a drug such as morphine. However, the morphine antibody will also bind drugs that are very similar in chemical structure to morphine. Codeine is very similar in chemical structure to morphine, as are three synthetic narcotics: Dilaudid (hydromorphone), Percodan (oxycodone), and Vicodin (hydrocodone). The immunoassay screening tests for opiates will detect to varying degrees all of these narcotics. This is true whether the screen is performed in a laboratory by OnLine or EMIT immunoassay, or by an on-site test such as the TesTcup or TesTstik™ device. The synthetic narcotics Darvon (propoxyphene), Demerol (meperidine), and methadone are not detected by the opiate immunoassays.
Heroin, morphine, codeine, Dilaudid, Percodan and Vicodin are all narcotic analgesics that can be abused and are addictive. A positive morphine screen with TesTcup and TesTstik can be caused by any of these drugs and, also, consumption of several teaspoons of poppy seeds. This is true with all opiate immunoassays, whether lab or on-site rapid screens.
Until recently, the GC/MS confirmation test for opiates generally measured only morphine and codeine. The presence of Dilaudid, Percodan, or Vicodin would not be detected by the opiate GC/MS confirmation, and the confirmation would be reported as NEGATIVE. A NEGATIVE opiate confirmation test may not indicate a false positive by the TesTcup on-site test, but rather that one of these synthetic narcotics is present in the urine specimen. To confirm the presence of these three synthetic narcotic drugs, an Expanded Opiate Confirmation test or Synthetic Narcotic confirmation test would need to be requested from the laboratory. Not all laboratories offer these GC/MS confirmations that include Dilaudid, Percodan, and Vicodin. One source of the Expanded Opiate Confirmation test is LabCorp.
On December 1, 1998, the Substance Abuse and Mental Health Services Administration (SAMHSA) that coordinates federal workplace drug test regulations changed the regulations for opiate testing. Prior to that date, the initial screen by immunoassay and the morphine and codeine confirmation tests was to have cutoffs of 300 ng/mL. Medical Review Officers and Probation Officers had difficulty differentiating a positive test for opiates caused potentially from heroin use from a potential poppy seed positive. The SAMHSA change on December 1, 1998, raised the screen and confirmation cutoffs to 2,000 ng/mL to eliminate most poppy seed positives. They also added 6-acetylmorphine to the confirmation test by GC/MS. The presence of 6-acetylmorphine, the metabolite of heroin, will conclusively show recent heroin use. For workplace drug testing, the SAMHSA opiate changes make sense. It is important not to falsely accuse someone of illicit heroin use, and detecting heroin use is the primary purpose of opiate testing in workplace testing.
However, the 6-acetylmorphine metabolite is detectable in urine for only several hours after use of heroin, while morphine is detectable above the 2,000 ng/mL for about a day. It has been shown that consumption of poppy seeds in most cases will not result in a morphine concentration of 2,000 ng/mL or greater. With no 6-acetylmorphine found, detecting the presence of morphine or codeine. Codeine can be present from use of codeine and from use of heroin. If the codeine level is higher than the morphine level, the source is probably codeine use. Raising the cutoff for opiates from 300 ng/mL to 2,000 ng/mL reduces the time window of detection for heroin, morphine and codeine to about a day after use. It, also, eliminates most poppy seed positives.
The certified drug testing labs have all switched to the 2,000 ng/mL opiate cutoff and many will no longer offer the lower 300 ng/mL cutoff. For criminal justice testing, when confirming a TesTcup morphine positive at the 300 ng/mL cutoff, it is important to use a lab cutoff of 300 ng/mL as well. The TesTcup has had a morphine/opiate test at the 2,000 ng/mL cutoff available since April 1999.
Reliability study of Varian, Inc. Diagnostics TesTstik screening for amphetamine, cocaine, marijuana, and morphine in urine. Bogema, S.C., Forensic Testing, Inc., Clifton, VA.
Testing for drugs of abuse in urine has become commonplace in the US criminal justice system. The technology of immunoassay has expanded from reagent systems for laboratories to disposable devices for point-of-care testing. On-site drug testing allows immediate identification of presumptive positive and negative specimens. The Varian, Inc. Diagnostic (RD) OnTrak TesTstik product is an immunoassay device intended for on-site screening for individual drug classes at DHHS/DOT cutoffs in urine. The objective of this study was to determine the reliability of the TesTstik device for initial screening of amphetamine (AMP), cocaine metabolite (COC), morphine (MOR), and marijuana metabolites (THC). The study consisted of two parts: 1) a precision study to determine the accuracy of the stated cutoffs, and 2) a clinical study of negative and positive patient specimens to determine specificity.
The precision study consisted of testing calibrator urine solutions at 50, 75, 125, and 150% of the DHHS/DOT cutoffs (N=20). Results below are percent negative results for each cutoff:
CUTOFF |
AMP |
COC |
MOR |
THC |
50% |
100% |
85% |
100% |
100% |
75% |
95% |
55% |
100% |
85% |
125% |
30% |
5% |
30% |
0% |
150% |
10% |
0% |
5% |
0% |
The clinical study showed 0% false positives for all drug classes (N=50). The clinical study showed 0% false negatives for all drug classes (N=50). The RDC Online immunoassay was used for laboratory comparison. All positive specimens for amphetamines were confirmed by GC-MS for amphetamine greater than the DHHS cutoff of 1000 ng/mL.
TesTstik provides the screen result in several minutes and is simple to use. The TesTstik is dipped into the urine specimen, removed after 10 seconds, and a cover pulled over the dipped portion of the device. A Test Valid window indicates when the test is complete. The presence of a blue line in the Test Result window indicates a negative result.
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