Log me on automatically each visit
It is currently Fri Dec 01, 2023 3:14 pm
Post a new topic Post a reply  [ 1 post ]   
Author Message
PostPosted: Sat May 30, 2015 12:07 pm 
Site Admin
User avatar

Joined: Wed May 27, 2015 10:20 am
Posts: 511 ... sting-lab/

What are the biggest changes in drug testing since you entered the field in 1977?
Testing procedures have changed dramatically in terms of specificity and sensitivity of detection since I began working in this area in the late 1970s. I have witnessed the introduction of newer approaches to testing that are characterized by dramatically increased sensitivity and specificity as well as the use of automation and high-speed data processing and data analysis.

Gas chromatography with electron capture detection and thin layer chromatography were the primary screening procedures available for my use in the Ohio laboratory from the late 1970s to the mid-1980s when the first ELISA tests specifically developed to detect drugs and related substances in urine samples from horses were introduced. Many laboratories quickly changed their testing programs to include a few to many ELISA tests in order to detect substances that were not detectable using thin layer chromatographic methods. For the past decade or so liquid chromatography with mass spectrometric detection has become the method of choice for screening test samples for regulated and prohibited drugs and the use of ELISA methods has declined steeply except in a few laboratories. The scope of coverage of prohibited and regulated substances that is possible with the use of instrumental methods of analysis cannot be duplicated by ELISA methods and is substantially less expensive per detectable substance. The specificity of instrumental methods of analysis is a distinct advantage because it is possible to learn the identity of a substance in the screening test.

The term “super test” was created about a decade ago. When we hear that term, what does it mean?
The “super test” is a term used to describe an expanded menu of tests and is typically used to describe tests performed on samples collected from horses in graded stakes races. The term was introduced in the late 1990s when laboratories relied primarily on ELISA tests to screen samples for prohibited and regulated substances. Most laboratory budgets did not allow a laboratory to purchase all commercially available ELISA kits so most were forced to select certain tests from the available tests to test samples. The number of tests that they performed on each sample was dictated largely by budget and the test menu was varied over time to provide expanded coverage of prohibited and regulated substances. The “super test” then was a test that utilized an expanded menu of ELISA tests compared to the menu used to test routine samples.

For those few laboratories that still use ELISA tests as their primary means of detecting substances in test samples test rotation is used to provide expanded coverage. These laboratories may use an expanded menu of tests or a “super test” to test certain samples or samples from stakes races.

For HFL Sport Science the term “super test” is not applicable because all samples received by the laboratory are tested by a comprehensive menu of instrumental based methods designed to detect the broadest range of prohibited and regulated substances that goes beyond what can be achieved by the use of an expanded menu of ELISA tests. All samples are subjected to the same intense scrutiny whether they were collected from the Kentucky Derby or an isolated county fair.

Another term often used is “zero tolerance.” What is its meaning to someone in drug testing?
For each substance there is a concentration below which the substance can no longer be detected by that method. That concentration of substance is defined as the limit of detection of the method for that substance. If we change the method to a more sensitive one, the limit of detection for that substance will be lower in the more sensitive test. Limits of detection are not values that we set but they are values that are determined by the physicochemical properties of the substances that we want to detect and by the methods that we chose to use.

“Zero tolerance” then refers to a policy under which a substance will be reported if the laboratory detects it. In other words it is the limit of detection of the method for each substance that determines the lowest concentration of the substance that will be reported.

One of the consequences of the use of a “zero tolerance” policy is that the concentration at which a substance will be reported will differ from one laboratory to another and within the same laboratory from time to time as new methods with different sensitivities are introduced.

A “zero tolerance” policy is based solely on the analytical methodology and not on the pharmacology of the drug. For those substances such as dermorphin and etorphine that should never be present in a horse at any concentration, a “zero tolerance” policy is appropriate and the introduction of new methods with lower limits of detection without notice is proper.

On the other hand, the use of a “zero tolerance” policy for therapeutic substances is not appropriate because it contributes substantially to differences between racing jurisdictions and makes compliance with rules more difficult particularly if methodology is changed without notice to veterinarians.

What are the biggest challenges you face in the drug-testing field, and how do you deal with them?
One of the biggest threats is the introduction of protein based drugs such as human recombinant erythropoietin and peptide drugs such as dermorphin because these substances are larger than most of the drugs that our methods are designed to detect and therefore present analytical challenges that are sometimes difficult to overcome. There are many peptides that have the potential to affect the horse. Because peptides are readily synthesized, it is possible for unscrupulous persons to obtain them with little effort. It will require concerted efforts of those involved in racing combined with appropriate penalties to deter the use of these substances.

The excessive use of therapeutic substances with thresholds threatens to overwhelm laboratories in some racing jurisdictions because the effort required to confirm a phenylbutazone or flunixin overage is comparable to the effort required to confirm the presence of dermorphin in a blood or urine sample. Consequently, laboratory resources are being severely stretched to meet these needs and to report findings in a timely manner. The ARCI’s new penalty guidelines for multiple medication violations may be of assistance if it acts as a deterrent to repeated medication violations.

Several racing commissions provided substantial amounts of research funding to racing laboratories in the 1980s and 1990s but most of these sources of funding have been lost. Those research funds were essential for developing new methods and for identifying new substances with the potential to affect performance. Identification of new sources of research finding is essential if we are to continue to detect newer substances..

OfflineProfileReply with quote
Display posts from previous:  Sort by  
Post a new topic Post a reply  [ 1 post ] 

Who is online

Users browsing this forum: No registered users and 1 guest

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum
Search for:
Jump to: