SOFT 2004 Meeting Abstracts - Society of Forensic Toxicologists

F24
A COMPARISON OF THE MICROGENICS DRI® OPIATE AND MICROGENICS DRI®
OXYCODONE IMMUNOASSA YS WITH GAS CHROMATOGRAPHY IMASS SPECTROMETRY
FOR THE DETECTION OF OPIATES AND OXYCODONE IN URINE
Joseph R. Monforte, Ph.D., DABFT *, Ronald Backer, Ph.D., DABFT and Alphonse PokJis, Ph.D.,
DABFT
Oxycodone is a semi-synthetic opioid prescribed for pain management of moderate to severe pain. It is
considered to have a high abuse potential and is prescribed as oxycodone HCl in preparations such as
Oxycontin® (a controlled- release preparation), Percodan® (with aspirin) and Percocet® (with
acetaminophen). Oxymorphone and noroxycodone are metabolites of oxycodone. Oxymorphone is a
potent analgesic while noroxycodone is relatively inactive.
Various immunoassays are available for the detection of opiates in urine. These assays generally have
lower sensitivities to oxycodone and oxymorphone. Consequently, oxycodone may not be detected
employing available opiate assays, even when taken under abused conditions. The Microgenics DRI®
Oxycodone Assay uses specific antibodies that can detect oxycodone and oxymorphone without significant
cross-reactivity from other opiates. The assay employs either a 100ng/mL or a 300ng/mL cutoff.
Seventy specimens received from pain management patients were tested for opiates with the Microgenics
DRI® Opiate and Microgenics DRI® Oxycodone Immunoassays, and gas chromatography/mass
spectrometry. Immunoassay reagents were employed as directed by the manufacturers. The cutoff for the
Microgenics DRI® Opiate Assay was 300 ng/mL, and the cutoff for the Microgenics DRI® Oxycodone
Assay was
100 ng/mL. The GC/MS SIM procedure employed hydrolysis of the specimen, treating the urine with
hydroxylamine, a solid phase column extraction, and formation of the BSTF A derivative. The method'
detects oxycodone, oxymorphone, hydrocodone, morphine and codeine. The limit of detection and limit of
quantitation is 20 ng/mL for each opiate.
Of the seventy specimens tested by the Microgenics DRI® Opiate Assay, fifty-three (53) specimens tested
positive and seventeen specimens tested negative. All seventeen negative specimens were confirmed
negative for the opiates included in the GC/MS SIM procedure and all seventeen specimens tested negative
for oxycodone using theMicrogenics DRI® Oxycodone Assay. An opiate was detected by GCIMS in all of
the specimens testing positive by the Microgenics DRI® Opiate Assay with four exceptions.
Of the seventy specimens tested by the Microgenics DRI® Oxycodone Assay, twenty-four specimens tested
positive for oxycodone. All twenty-four specimens tested positive for oxycodone by GCIMS, and twentytwo
of the specimens also contained oxymorphone. One specimen, which did not contain a reportable
oxymorphone concentration, also contained morphine (4,679 ng/mL). One specimen tested one point
below the Microgenics DRI® Oxycodone cutoff and contained morphine (18, 522 ng/mL) but no reportable
oxycodone. All forty-six specimens, which tested negative for oxycodone with the Microgenics DR1®
Oxycodone Assay, also tested negative for oxycodone and oxymorphone by GC/MS.
The results obtained with this limited number of specimens indicates that the Microgenics DRI®
Oxycodone Assay is highly specific for oxycodone and, consequently, has the potential to be very effective
in discriminating oxycodone from other opiates which may be present in a urine specimen.
Keywords: Oxycodone, Immunoassay, Gas ChromatographylMass Spectrometry
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