Wednesday, July 1, 2009

Welcome to all readers of my blog.

I hope to present a forum in which we can discuss any and all issues relating to drug testing. As you know, there are many types of drug tests administered in many different settings. Drug tests may be conducted by law enforcement, in court settings, as a requirement of employment and for medical evaluations (to name a few). I hope to present issues of interest to people in all walks of life and answer questions, to the best of my ability, that I routinely receive in my practice of forensic toxicology.

To start , I would like to outline some of the common types of tests so you can become familiar with the terminology:

ELISA (Enzyme Labeled ImmunoSorbent Assay) is the screening technology used for hair drug testing and oral fluid drug testing. This technique involves the mixing of specifically developed antibodies with the patient’s sample. These antibodies are designed to attach specifically to drugs or drug metabolites. The specific antibodies selectively will attach to drugs present in the patient’s hair or oral fluid. Automated instrumentation is used to detect this attachment of antibody to drug. If this specific attachment occurs the specimen is considered positive for the drug detected.

EMIT (Enzyme Multiplied Immunoassay Technique) is the screening technology used for urine drug testing. This technique utilizes essentially the same principles as the ELISA testing.

GC/MS (Gas Chromatograph/Mass Spectrometry) is considered a confirmatory testing technique. It is universally considered the “Gold Standard” in drug testing. This procedure involves the purification of a specimen (Hair, oral fluid or urine) by the gas chromatograph and the positive identification of the purified drug by the mass spectrometer. The mass spectrometer produces the mass spectrum of the drug undergoing confirmation. The mass spectrum is as unique to a drug as a fingerprint is to an individual. The GC/MS technique provides absolute information about drugs and drug metabolites in biological specimens.

Whereas drug screening, by either ELISA or EMIT, is an extremely reliable indicator of drug use, no screening test provides 100% accuracy. Only GC/MS testing can approach this level of accuracy.

If you have any questions about the topics covered you may email me at or visit my website: