Detection Time for THC in Oral Fluid After Frequent Cannabis Smoking

Abstract

The study shows that frequent use of high dosages of cannabis may lead to prolonged detection times, and that positive samples can be interspersed among negative samples. These results are of great importance when THC results from oral fluid analyses are to be interpreted.

Extended Detection of Amphetamine and Methamphetamine in Oral Fluid

“…From the creatinine-correlated concentrations in corresponding urine samples, new ingestions were not suspected. This phenomenon also was observed in urine samples 4,6 and was reported also for THC 26,27 and benzodiazepines. 28 Detection times in different matrices are highly dependent on cutoff concentrations; lowering the cutoff inevitably leads to longer detection times.…”

Interpreting oral fluid drug results in prisoners: monitoring current drug intake and detection times for drugs self-administered prior to detention

“…2 and 3) of creatinine-normalized urine results were used for comparison to see if variation in oral fluid results was likely to be the result of new intake during the study. There was a larger variability in elimination curves in oral fluid as compared to creatinine corrected urine curves, in line with the previous findings [27][28][29][30]. In addition, after ingestion of high and repeated drug doses, detection times could be several days.…”

“…Multiple studies documented that oral fluid is a viable matrix for drugs of abuse detection [10][11][12][13][14][15]. Single and low doses are typically administered in controlled drug studies [16][17][18][19][20][21][22][23][24][25][26], although others investigating drug elimination purported high doses from patients admitted for drug detoxification [27][28][29][30] or after chronic frequent use [31; 32] reported increased drug detection times. Since many prisoners use high and/or chronic doses of drugs of abuse before incarceration, elimination and detection times of drugs of abuse in oral fluid from this population provide relevant data for future interpretation of oral fluid tests.…”

Risk for involvement in road traffic crash during acute cannabis intoxication

“…The pharmacokinetics varies between individuals due to variations in metabolic rates and re‐distributions; the elimination half‐life of THC ranges from hours to days . Among occasional users, the THC concentration declines to less than 1 ng/mL in blood 4–12 hours after smoking a cannabis dose of 20–30 mg THC for most, but not all subjects, whereas among frequent users, more than 24 hours are needed to achieve a THC concentration in blood below 1 ng/mL in most cases , mainly because THC is distributed into adipose tissue and released slowly back into the blood. Urine samples are normally analysed for carboxy‐THC (THC‐COOH), which is an inactive metabolite.…”