Validity testing of the EZ-SCREEN cannabinoid test.
Recently, a number of "quick tests" became available for use in on-site drug testing. These tests offer advantages in simplicity, ease of performance, and rapid access to test results. However, there is a paucity of data on the validity of these tests for the detection of drugs of abuse. This report describes a validity study of the EZ-SCREEN cannabinoid test for the detection of cannabinoids in urine. Three healthy, male volunteers with a history of marijuana use participated in the study. Each subject smoked 1, 2, or 4 marijuana cigarettes (2.6% THC) on each test day. Urine samples were collected and incorporated into a specimen set consisting of 178 clinical urine samples, 72 urine samples containing known amounts of drug, and 50 drug-free urine samples. The specimen set was randomized and analyzed under blind conditions by the EZ-SCREEN test and by GC/MS for 11-nor-9-carboxy-delta 9-tetrahydrocannabinol (THCCOOH). Results were interpreted independently by three readers. Concordance analysis was performed by comparison of results of the EZ-SCREEN test with GC/MS. The EZ-SCREEN test was highly sensitive and produced positive results at a standard THCCOOH concentration of 5 ng/mL. While showing high sensitivity to THCCOOH, the assay demonstrated low cross-reactivity with delta 9-tetrahydrocannabinol (THC) and other cannabinoids. No false-positive results were recorded with 50 drug-free urine samples, but one reader recorded eight undecided results. Overall agreement between the three readers for the EZ-Screen results was approximately 80%. Delayed readings and photocopy readings tended to be less accurate than readings obtained at 3 min.(ABSTRACT TRUNCATED AT 250 WORDS)
Jenkins
A J
AJ
Addiction Research Center, NIDA, Baltimore, MD 21224.
Mills
L C
LC
Darwin
W D
WD
Huestis
M A
MA
Cone
E J
EJ
Mitchell
J M
JM
D000328:Adult; D002186:Cannabinoids / Q000652:urine*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000175:diagnosis*; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015813:Substance Abuse Detection / Q000295:instrumentation* / Q000379:methods
D002186:Cannabinoids