Pain Management and Drugs of Abuse Measured in Urine or Oral Fluid
The measurement of drugs of abuse in urine and/or oral fluid is common for pre-employment screening and DOT / federally mandated testing. However, the most rapid expansion of testing has been in the fields of law enforcement and compliance monitoring / diagnostic evaluation by physicians. Although many methods are available for these measurements, the fastest growing and preferred approach is liquid chromatography tandem mass spectrometry (LC/MS/MS) because of the high degree of certainty it affords determining concentration and identification of compounds. While the continued growth of the use of LC/MS/MS for the measurement of drugs of abuse in urine and oral fluid seems certain, there are still several technical challenges that need to be met. These needs include being able to easily measure low-dose drugs at or near 1ng/g concentration (for medical purposes, Pesce, et. al. 2012 AACC conference and zero tolerance testing), simplicity for performing measurements by lab technicians with relatively little training, and the ability to achieve high throughput for all work while minimizing the labor and number of workflows required.
In an effort to meet these needs, Instrument Top Sample Prep Solutions, Inc. (ITSP) along with Assurance Scientific Laboratories has developed the automated on-line ITSP-LC/MS/MS method described here. This ITSP solution uses Solid Phase Extraction (SPE) to clean and pre-concentrate urine or oral fluid samples so that low-dose drugs at or near 1ng/g concentration are easily measured at S/N ≥20. At the same time, the method’s design is balanced to identify and measure all of the drugs (acidic and basic drugs as well as polar and non-polar drugs) in one ITSP SPE method, all in one LC/MS/MS workflow. It is simple, robust, and can be performed by lab technicians with MS familiarity. It is completely automated from sample plates or vials to results (using the native MS software) and can process two 96-well plates of samples overnight per LC/MS/MS. The results will be waiting for you in the morning.
Total automation is achieved using the PAL System LC sample handler (the most commonly used autosampler for GC/MS/MS and LC/MS/MS worldwide). Since one must invest in an autosampler as a prerequisite to LC/MS/MS, we recommend choosing one that can prepare the sample as well as inject it. The cycle time achieved for on-line ITSP-LC/MS/MS is 4.5 minutes for 71 drugs (opiates, metabolites, illicits, opioids, barbs, benzos, and THCA).