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Originally Posted by prudery
The horse had 45 nanograms of caffeine show up .
A nanogram is one BILLIONTH of a gram .
A gram is one FORTIETH of an ounce .
I would say that is a trace positive. Corect me if I am wrong ...
How stimulating is that little amount of caffeine in a thousand pound animal going to be--a billionth of a one fortieth of an ounce ???
Something is not right here ...
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Caffeine can be a metabolite of theophylline (given for breathing problems), given outright by itself, or an environmental contaminant.
Interestingly, I couldn't find caffeine by itself in the RMTC model rules (although theophylline is there).
I did find this (I highlighted the take-home):
Journal of applied toxicology :
Effects of caffeine on locomotor activity of horses: determination of the no-effect threshold J Appl Toxicol. 2001 May-Jun;21(3):229-34.
Abstract
Caffeine is the legal stimulant consumed most extensively by the human world population and may be found eventually in the urine and/or blood of race horses. The fact that caffeine is in foods led us to determine the highest no-effect dose (HNED) of caffeine on the spontaneous locomotor activity of horses and then to quantify this substance in urine until it disappeared.
We built two behavioural stalls equipped with juxtaposed photoelectric sensors that emit infrared beams that divide the stall into nine sectors in a 'tic-tac-toe' fashion. Each time a beam was interrupted by a leg of the horse, a pulse was generated; the pulses were counted at 5-min intervals and stored by a microcomputer. Environmental effects were minimized by installing exhaust fans producing white noise that obscured outside sounds. One-way observation windows prevented the animals from seeing outside. The sensors were turned on 45 min before drug administration (saline control or caffeine).
The animals were observed for up to 8 h after i.v. administration of 2.0, 2.5, 3.0 or 5.0 mg caffeine kg(-1).
The HNED of caffeine for stimulation of the spontaneous locomotor activity of horses was 2.0 mg kg(-1).
The quantification of caffeine in urine and plasma samples was done by gradient HPLC with UV detection.
The no-effect threshold should not be greater than 2.0 microg caffeine ml(-1) plasma or 5.0 microg caffeine ml(-1) urine.
The horse in question had 45 nanograms of caffeine in the blood (plasma) which is indeed alot less than 2 micrograms, so you're right, there was probably no effective stimulation of the horse whatsoever.
Edit: And again, this begs the question of what limits do we put on drugs found on raceday, considering that testing is so precise and can detect incredibly small amounts of drugs.
The easiest answer is to say, "nothing should be found" - but then you get innocent positives.