So you’ve sent your specimen off to the laboratory, what happens next?
Laboratory specimen testing goes through a series of steps after the specimen collection occurs and we are going to take a look at each of these steps to understand what happens. Laboratory tests which are done in Canada under the DOT (U.S. Department of Transportation) must be performed in a laboratory accredited by the Substance Abuse and Mental Health Services Administration (one of the U.S. regulatory bodies which oversee drug and alcohol testing), however, non-DOT (Canadian) testing is not required to comply with those regulations.
Laboratory Accessioning and Screening
When a specimen is received at the laboratory the first step is for them to accession it, which involves the laboratory taking over custody of the specimen and giving it an internal tracking number, the accession number. After the specimen has been accessioned it will be sent on for laboratory screening using similar technology as what is used for on-site screening tests.
Laboratories normally use an Enzyme Immunoassay (EIA) to test for the presence of drugs in a specimen. This test involves a specialized enzyme mixed with drug-specific antibodies. If the drug is present in the specimen, an active enzyme forms, creating a change in colour that can be measured on a device called a spectrophotometric analyzer. The amount of enzyme formed is proportional to the amount of analyte that is present in the specimen.
If this screen is a non-negative then the specimen will be sent on for further, confirmation testing.
The two types of confirmation tests that are used in the laboratory are Gas Chromatography/Mass Spectrometry (GC/MS) and Liquid Chromatography/Tandem Mass Spectrometry(LC/MS/MS). Either of these types of confirmation testing can be used to determine the quantitative amounts of the drug present in a specimen, which one is used generally depends on the type of specimen being tested.
Gas Chromatography/Mass Spectrometry is used for hair and urine specimens and functions by heating a specimen to 300 °C and observing the molecules passing through a chromatograph and a mass spectrometer. The mass spectrometer uses electrons to separate the molecules into ions and then the weights of each ion are analyzed to determine the precise amount of the drug(s) metabolite(s) present in the specimen.
Liquid Chromatography/Tandem Mass Spectrometry is used for oral fluid specimens and runs the liquid specimen through tandem spectrometers to isolate specific compounds to determine the amount of drug(s) metabolite(s) present.
Laboratory confirmation testing will confirm the exact amount of drug metabolites present in ng/mL(nanograms per millilitre) or pg/mL(picograms per millilitre). These results are then recorded on Copy 1 of the CCF by the certifying scientist as well as entered into the lab’s database and sent digitally to the appointed Medical Review Officer (MRO).
When the Medical Review Office receives the results they will first match the results to the CCF
Copy 2 to ensure document accuracy. If the test result received from the laboratory is negative, the test will be quality assured and verified as a negative, and released to the party that purchased the test. If the results come in from the laboratory as positive, then an interview between the donor and the MRO is required. The MRO office will try to contact the donor to allow them a chance to discuss their results with the Medical Review Officer. This interview with the MRO gives the donor an opportunity to explain any medical-related reasons for the positive result, such as being on medication.
To determine the final verified results the MRO will take into account any information the donor presented in the interview, as well as any documentation that was sent in to confirm that information, such as a prescription etc. The MROs final verification may depend on the regulatory body they are working under, or the specific requirements of an employer’s policy; for example, sites with a zero-tolerance policy for cannabis, usually due to safety-sensitive positions, will follow that policy, meaning even if the cannabis use is medicinal the final verification will remain a positive.
Once the final verification has been made by the MRO the result will be released to the party that paid for the test.
All parties involved have some form of record-keeping requirement when the collection of a specimen occurs.
- The collector has copies to ensure they are protected if a result is contested, they maintain their record for a minimum of 30 days.
- Labs maintain records for two years after any result.
- The MRO holds onto positive results for five years and negative results for two.
- The employer holds results for the same length as an MRO with the exception that they hold refusals for the same five years that you would a positive result.