Homogeneous enzyme immunoassay for cannabinoids in urine.

Abstract

We describe a homogeneous enzyme immunoassay for measurement of cannabinoid metabolites, as well as delta9-tetrahydrocannabinol (I) in urine. Malate dehydrogenase from pig heart mitochondria was labeled with a derivative of I. The compound used to calibrate the assay was the I metabolite, 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid (II). With 15 microgram of II per liter of urine as the cutoff concentration, the assay can detect 25 microgram of II per liter with greater than 95% confidence. A positive response was obtained for urine specimens assayed within 30 min after exposure to cannabinoids. However, the persistence of metabolites of I in urine indicates that assay of this fluid is useful as an indicator of cannabinoid use but not as an indicator of intoxication.

High prevalence of cannabis use among Aka foragers of the Congo Basin and its possible relationship to helminthiasis

“…It is predominantly excreted in urine as the ester‐linked glucuronide conjugate (Foltz, ). THCA is a superior biomarker to THC because it can be detected for several weeks following a single dose of THC (Agurell et al, ; Ellis et al, ) and it is more soluble and absorbs less onto the walls of storage containers (Rogers et al, ).…”

Self‐Report Methods

“…The low calibrator (20 mg/ml) is used as the cutoff value for positive/negative interpretation and ensures at least 95 percent confidence in the positive/negative classifications (DeLaurentis et al 1982). Levels of urinary metabolites are detectable within a few hours after exposure to marijuana (Rodgers et al 1978) and remain detectable 7 to 10 days after smoking (Clark et al 1980).…”