Meth in urine
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Methamphetamine Detection in Urine: Methods and Implications
Introduction to Methamphetamine Detection in Urine
Methamphetamine (METH) is a widely abused illicit drug, second only to marijuana in prevalence. Detecting METH in urine is crucial for both clinical and forensic purposes. Various methods have been developed to accurately identify and quantify METH in urine samples, each with its own advantages and limitations.
Active vs. Passive Exposure to Methamphetamine Vapor
A study on mice exposed to METH vapor revealed significant differences in urinary METH concentrations between active and passive exposure. Mice actively exposed to METH vapor had urine concentrations significantly above the detection limit even after 72-96 hours. In contrast, passive exposure resulted in urine concentrations below the detection limit within the first 24 hours. This suggests that passive exposure to METH vapor is unlikely to result in detectable levels of METH in human urine, which is important for legal contexts where individuals may claim passive exposure1.
Colorimetric Assays for Methamphetamine Detection
Recent advancements have introduced simple, sensitive, and visual colorimetric assays for detecting METH in urine. These methods utilize METH-specific aptamers and unmodified gold nanoparticles (AuNPs). The presence of METH causes a color change in the AuNPs solution from red to blue, which can be quantified visually or by measuring absorbance ratios. This method operates within a concentration range of 2 µM to 10 µM, with a detection limit of 0.82 µM, making it a fast and effective tool for METH detection in urine2 3.
G-Quadruplex-Hemin DNAzyme Molecular Beacon Probe
Another innovative method involves a G-quadruplex-hemin DNAzyme molecular beacon (DNAzyme MB) probe. This biosensor is cost-effective and label-free, utilizing a METH aptamer and a colorimetric substrate. In the presence of METH, the DNAzyme MB dissociates from its inactive hybrid, catalyzing a reaction that produces measurable signals. This method achieves a detection limit as low as 0.5 nM and shows high recovery rates for METH spiked in urine samples, indicating its potential for both biological and environmental applications4.
Comparative Analysis of Methamphetamine in Different Biological Matrices
A comprehensive study involving controlled dosing of METH in volunteers compared its disposition in oral fluid, plasma, and urine. Urine samples showed substantially higher METH concentrations compared to oral fluid and plasma. Detection times and rates were longer for urine, making it a more reliable matrix for METH detection over extended periods. This highlights the importance of selecting the appropriate biological matrix based on the detection window required6.
Implications for Public Health and Legal Contexts
The high prevalence of METH use, particularly among clients of harm reduction services, underscores the need for reliable detection methods. A study in British Columbia found that self-reported METH use had high validity when compared to urine toxicology screening, with a sensitivity and specificity of 86%. This suggests that urine testing is a reliable method for monitoring METH use in harm reduction settings5.
Conclusion
Detecting methamphetamine in urine is essential for both clinical diagnostics and forensic investigations. Advances in colorimetric assays and DNAzyme molecular beacon probes offer sensitive, fast, and cost-effective methods for METH detection. Understanding the differences in METH concentrations due to active and passive exposure, as well as the comparative analysis of different biological matrices, provides valuable insights for public health and legal applications. Reliable urine testing remains a cornerstone in the fight against METH abuse.
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Most relevant research papers on this topic
Comparative study between active and passive exposure of methamphetamine vapor in mice
Active methamphetamine exposure leads to higher urinary concentrations, while passive exposure results in extremely small amounts of METH in the urine, unrecognizeable by screening kits.
Erratum to: Colorimetric and bare eye determination of urinary methylamphetamine based on the use of aptamers and the salt-induced aggregation of unmodified gold nanoparticles
Urinary methylamphetamine (METH) can be detected using a simple colorimetric assay using a METH-specific aptamer and unmodified gold nanoparticles, with a detection limit of 0.82 M in human urine.
Colorimetric and bare eye determination of urinary methylamphetamine based on the use of aptamers and the salt-induced aggregation of unmodified gold nanoparticles
This colorimetric assay allows for ultrasensitive and specific detection of Methamphetamine (METH) in human urine, with a detection limit at 0.82 M.
G-quadruplex–hemin DNAzyme molecular beacon probe for the detection of methamphetamine
The G-quadruplex-hemin DNAzyme MB probe effectively detects methamphetamine in biological samples and environmental matrices, with a detection limit as low as 0.5 nM and minimal interference from common illicit drugs.
Crystal methamphetamine use in British Columbia, Canada: A cross-sectional study of people who access harm reduction services
Crystal meth was the most commonly used substance among clients of harm reduction sites in British Columbia in 2018, and was frequently used alongside opioids.
Observational Study
Rigorous JournalMethamphetamine Disposition in Oral Fluid, Plasma, and Urine
Oral fluid concentrations of methamphetamine are higher than plasma concentrations, with urine concentrations being substantially higher than oral fluid concentrations.
Literature Review
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Active methamphetamine users have higher HIV loads, but abstinence programs can effectively suppress viral replication in HIV-abusing populations.
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Baseline cocaine-positive urine results predict a lower response to desipramine treatment in buprenorphine- or methadone-treated cocaine-dependent patients.
RCTCathinone (Khat) and methcathinone (CAT) in urine specimens: a gas chromatographic-mass spectrometric detection procedure.
The developed gas chromatographic-mass spectrometric procedure effectively detects cathinone and methcathinone in urine specimens, with high recoveries and minimal variations.
Twenty-four-hour urinary excretion of ten pesticide metabolites in healthy adults in two different areas of Italy (Florence and Ragusa).
High percentage of 24-hour urine samples positive for several pesticide metabolites were found in healthy adults, with higher levels in urbanized areas compared to rural areas.
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