|
Test ID: U Cannab Scrn
|
|
Cannabinoid Screen Urine
|
|
|
|
Useful For
|
To detect drug intoxication or overdose and to screen for drug abuse involving cannabinoids.
|
|
Method name and description
|
Kinetic interaction of microparticles in solution (KIMS) as measured by changes in light transmission performed on the Roche cobas c-systems. In the absence of sample drug, soluble drug conjugates bind to antibody-bound microparticles, causing the formation of particle aggregates. As the aggregation reaction proceeds in the absence of sample drug, the absorbance increases. When a urine sample contains the drug in question, this drug competes with the drug derivative conjugate for microparticle-bound antibody. Antibody bound to sample drug is no longer available to promote particle aggregation, and subsequent particle lattice formation is inhibited. The presence of sample drug diminishes the increasing absorbance in proportion to the concentration of drug in the sample. Sample drug content is determined relative to the value obtained for a known cut-off concentration of drug.
|
|
Clinical information
|
The principal psychoactive component of the hemp plant, Cannabis sativa, is generally accepted to be Δ9 tetrahydrocannabinol (Δ9 THC).The acute effects of marijuana use, concomitant with the desired “high”, are memory impairment, time confusion, interference with learning, impaired motor skills and depersonalization.These effects are also manifested in chronic users in addition to cardiovascular, pulmonary, and reproductive effects. Marijuana is usually smoked, but may be ingested, either incorporated into food or as a liquid extract (tea). It is rapidly absorbed from the lungs into the blood with rapid onset of effects; the onset is slower but prolonged when ingested. The natural cannabinoids and their metabolic products are fat soluble and are stored in the body’s fatty tissues, including brain tissue, for prolonged periods after use. (Roche Cobas Cannabinoids II package insert).
|
|
|
Specimen type / Specimen volume / Specimen container
|
Specimen type: Random Urine (Spot Urine)
Minimum volume of 5 mL freshly voided urine in clean container or aliquoted tube.
|
|
Collection instructions / Special Precautions / Timing of collection
|
No preservative required. Urine specimens is recommended to be stored at 2‑8°C when delay in transport.
THC and its derivatives may adsorb onto plastics used for sample collection containers, effectively lowering the drug concentration of the sample.
|
|
Storage and transport instructions
|
Storage: 5 days at 2-8°C
Transport: 2-25°C
|
|
Specimen Rejection Criteria
|
Leaking specimen, contaminated sample, adulterated sample.
|
|
|
Biological reference intervals and clinical decision values
|
Qualitative assay for 50 ng/mL cut-off
Negative: < 50 ng/mL
Positive: > 50 ng/mL
(This is a screening test; results have to be considered in the clinical setting only. Other than clinical use, it is mandatory to confirm results with a definitive method.)
|
|
Factors affecting test performance and result interpretation
|
With a low cutoff assay for cannabinoids, it may be possible to obtain a preliminary positive test result from a non‑user as a result of passive inhalation.
|
|
Turnaround time / Days and times test performed / Specimen retention time
|
Daily (24/7)
Turn-around time:
STAT: 1 hour
Routine: One working day
Specimen Retention: 4 days
|
|
|
