High prevalence of 6-acetylmorphine in morphine-positive oral fluid specimens.

Identification of 6-acetylmorphine, a specific metabolite of heroin, is considered to be definitive evidence of heroin use. Although 6-acetylmorphine has been identified in oral fluid following controlled heroin administration, no prevalence data is available for oral fluid specimens collected in the workplace. We evaluated the prevalence of positive test results for 6-acetylmorphine in 77,218 oral fluid specimens collected over a 10-month period (January-October 2001) from private workplace testing programs. Specimens were analyzed by Intercept immunoassay (cutoff concentration=30 ng/ml) and confirmed by GC-MS-MS (cutoff concentrations=30 ng/ml for morphine and codeine, and 3 ng/ml for 6-acetylmorphine). Only morphine-positive oral fluid specimens were tested by GC-MS-MS for 6-acetylmorphine. A total of 48 confirmed positive morphine results were identified. An additional 107 specimens were confirmed for codeine only. Of the 48 morphine-positive specimens, 32 (66.7%) specimens were positive for 6-acetylmorphine. Mean concentrations (+/-S.E.M.) of morphine, 6-acetylmorphine and codeine in the 32 specimens were 755+/-201, 416+/-168 and 196+/-36 ng/ml, respectively. Concentrations of 6-acetylmorphine in oral fluid ranged from 3 to 4095 ng/ml. The mean ratio (+/-S.E.M.) of 6-acetylmorphine/morphine was 0.33+/-0.06. It is suggested that, based on controlled dose studies of heroin administration, ratios >1 of 6-acetylmorphine/morphine in oral fluid are consistent with heroin use within the last hour before specimen collection. The confirmation of 6-acetylmorphine in 66.7% of morphine-positive oral fluid specimens indicates that oral fluid testing for opioids may offer advantages over urine in workplace drug testing programs and in testing drugged drivers for recent heroin use.

Oral fluid testing for drugs of abuse: positive prevalence rates by Intercept immunoassay screening and GC-MS-MS confirmation and suggested cutoff concentrations.

Draft guidelines for the use of oral fluid for workplace drug testing are under development by the Substance Abuse and Mental Health Services Administration (SAMHSA) in cooperation with industry and researchers. Comparison studies of the effectiveness of oral fluid testing versus urine testing are needed to establish scientifically reliable cutoff concentrations for oral fluid testing. We present the results of the first large scale database on oral fluid testing in private industry. A total of 77,218 oral fluid specimens were tested over the period of January through October 2001 at LabOne. Specimens were screened by Intercept immunoassay at manufacturer's recommended cutoff concentrations for the five SAMHSA drug categories (marijuana, cocaine, opiates, phencyclidine, and amphetamines). Presumptive positive specimens were confirmed by gas chromatography-tandem mass spectrometry. A total of 3908 positive tests were reported over the 10-month period, representing a positive rate of 5.06%. Of the five drug categories, marijuana and cocaine accounted for 85.75% of the positives. The pattern and frequency of drug positives showed remarkable similarity to urine drug prevalence rates reported for the general workforce according to the Quest Diagnostics' Drug Testing Index over the same general period, suggesting that oral fluid testing produces equivalent results to urine testing. The data on oral fluid testing also revealed a surprisingly high 66.7% prevalence of 6-acetylmorphine confirmations for morphine positives suggesting that oral fluid testing may be superior in some cases to urine testing. Comparison of oral fluid drug concentrations to SAMHSA-recommended cutoff concentrations in Draft Guidelines indicated that adoption of the screening and confirmation cutoff concentrations of Draft Guidelines #3 would produce the most consistent reporting results for all drug classes except amphetamines. Consequently, it is suggested that the final Guidelines adopt the screening and cutoff concentrations listed in Draft Guidelines #3 with the exception of lowering the amphetamines cutoff concentrations (screening/confirmation) to 50/50 ng/mL for amphetamine and methamphetamine.