Detection of Drugs in Nails (fingernails and toenails): Three Year Experience

Nails (fingernails and toenails) are made of keratin. As the nail grows, substances incorporate into the keratin fibers where they can be detected 3-6 months after use. Samples are collected by clipping of 2-3 mm of nail from all fingers (100 mg). We present drug testing results from 10,349 nail samples collected from high-risk cases during a 3-year period of time. Samples were analyzed by validated analytical methods. The initial testing was performed mostly using enzyme-linked immunosorbent assay, but by liquid chromatography-tandem mass spectrometry (LC-MS-MS) as well. Presumptive positive samples were subjected to confirmatory testing with sample preparation procedures including washing, pulverizing, digestion and extraction optimized for each drug class. 

The total of 7,799 samples was analyzed for amphetamines. The concentrations ranged from 40 to 572,865 pg/mg (median, 100-3,687) for all amphetamine analytes. 

• Amphetamine and methamphetamine were present in 14% of the samples, 
• 22 samples were positive for 3,4-methylenedioxymethamphetamine (0.3%), 
• 7 for methylenedioxyamphetamine (0.09%) 
• and 4 for 3,4-methylenedioxy-N-ethylamphetamine (0.05%). 
• Cocaine and related analytes were found in 5% samples (7,787 total), and the concentration range was 20-265,063 pg/mg (median 84-1,768). 
• Opioids overall ranged from 40 to 118,229 pg/mg (median 123-830). 
• The most prevalent opioid was oxycodone (15.1%) and hydrocodone (11.4%) 
• compared with 1.0-3.6% for the others, including morphine, codeine, hydromorphone, methadone, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine and oxymorphone. 
• Carboxy-Δ-9-tetrahydrocannabinol positivity rate was 18.1% (0.04-262 pg/mg, median 6.41). 
• Out of 3,039 samples, 756 were positive (24.9%) for ethyl glucuronide (20-3,754 pg/mg, median 88). 
• Other drugs found in nails included barbiturates, benzodiazepines, ketamine, meperidine, tramadol, zolpidem, propoxyphene, naltrexone and buprenorphine. 

Nail analyses have become a reliable way of determining the long-term use and abuse of drugs. Extraction techniques are simple and produce accurate and precise results. Sensitive analytical instrumentation, mainly LC-MS-MS, allows for detection of femtogram (10(-15) g) quantities of substances in nails. Samples were from a high-risk population, therefore the extraordinary positivity rate was observed.

Via:  http://ht.ly/SsNUz 

By: Shu I1, Jones J1, Jones M1, Lewis D1, Negrusz A2.

• 1United States Drug Testing Laboratories, Inc., 1700 South Mount Prospect Road, Des Plaines, IL 60017, USA.
• 2United States Drug Testing Laboratories, Inc., 1700 South Mount Prospect Road, Des Plaines, IL 60017, USA

Workplace Drug Testing on Urine Samples: Evidence for Improving Efficacy of a First-Level Screening Program

Previous reports revealed poor performance in identifying drugs of abuse users through first-level workplace drug testing (WDT), based on urine samples. In a cross-sectional study, we evaluated: (i) the effect of creatinine normalization of drug values from diluted urine samples (creatinine levels ≤20 mg/dL) on the prevalence of drug users; (ii) the independent procedure-related predictors of positivity and dilution.

Workers' urine samples were collected at the workplace or at our certified laboratory between 2008 and 2012. All samples were analysed for drugs of abuse by immuno-enzymatic method in our laboratory, according to the Italian WDT law. Detectable drugs of abuse concentrations lower than the positive cutoff values were normalized based on mean levels of urinary creatinine. Detectable concentrations of drugs were confirmed by GC/MS. Multivariate logistic regression was used to detect independent procedure-related predictors of positive and diluted urine samples.

Of the 3080 urine samples screened, 51 (1.7%) were found positive for some drugs of abuse (26 cannabinoids and 16 cocaine) and 116 (3.8%) were diluted. Seventeen out of 23 diluted urine samples with detectable concentrations of cannabinoids or cocaine were found positive after urine creatinine normalization and GC/MS confirmed both negative and positive results. This increased the percentage of positivity for cannabinoids and cocaine from 1.35% to 2.09% (+55%, p=0.0005), which is closer to the expected prevalence of drug users based on Italian self-reported surveys. Collection of samples in the laboratory was an independent predictor of positivity (OR=2.33, 95%CI 1.27-4.28) and diluted urine sample (OR=1.65, 95%CI 1.04-2.61).

Efficacy of first-level  WDT could be improved by well-controlled pre-analytical procedures and urine creatinine normalization of detected concentrations of drugs of abuse.

Via:  http://ht.ly/Ss1yt 

By: Crespi V1, Maio RC, Veronesi G, Gianfagna F, Taborelli S, Ferrario MM.

1Toxicology Laboratory, Occupational and Preventive Medicine, Varese Hospital, Varese, Italy.

Ethnic Hair Care Products May Increase False Positives in Hair Drug Testing

The question of why different races appear more susceptible to hair contamination by external drugs remains controversial. This research studied susceptibility of head hair to external cocaine and methamphetamine when hair products have been applied. Three different chemical classes of ethnic hair products were applied to Caucasian, Asian, and African hair. 

Some products increased the methamphetamine and cocaine concentrations in all hair types. A unique finding of this research is that certain ethnic hair products can replace moisture as a diffusion medium, thereby increasing the susceptibility to contamination over 100-fold compared to petroleum-based products.

Via: http://ht.ly/RU69p

By: Kidwell DA1, Smith FP2, Shepherd AR3.

• 1Chemistry Division, Naval Research Laboratory, Washington, DC 20375, United States.
• 2University of New Haven, West Haven, CT 06516, United States. Electronic address: NRLSummerResearchFaculty@gmail.com.
• 3American Society for Engineering Education Science and Engineering Apprenticeship Program, United States.