NHA LABORATORY
International Prohibited / Forbidden Substance Thresholds

The International Federation of Horseracing Authorities have established international thresholds for:

  • substances endogenous to the horse
  • substances arising from plants traditionally grazed or harvested as equine feed
  • substances in equine feed arising from contamination during cultivation, processing or treatment, storage, or transportation.
As a International Federation of Horseracing Authorities member the National Horseracing Authority of Southern Africa apply these threshold / concentrations which are provided below.

Arsenic
  • 0.3 microgram total arsenic per millilitre in urine
Boldenone
  • 0.015 microgram free and conjugated boldenone per millilitre in urine from male horses (other than geldings)
Carbon dioxide
  • 36 millimoles available carbon dioxide per litre in plasma
Cobalt
  • 0.1 microgram total cobalt per millilitre in urine
Dimethyl sulphoxide
  • 15 micrograms dimethyl sulphoxide per millilitre in urine, or
  • 1 microgram dimethyl sulphoxide per millilitre in plasma
Estranediol in male horses (other than geldings)
  • 0.045 microgram free and glucuroconjugated 5α-estrane-3β,17α-diol per millilitre in urine
Hydrocortisone
  • 1 microgram hydrocortisone per millilitre in urine
Methoxytyramine
  • 4 micrograms free and conjugated 3-methoxytyramine per millilitre in urine
Salicylic acid
  • 750 micrograms salicylic acid per millilitre in urine, or
  • 6.5 micrograms salicylic acid per millilitre in plasma
Testosterone
  • 0.02 microgram free and conjugated testosterone per millilitre in urine from geldings, or 
  • 0.055 microgram free and conjugated testosterone per millilitre in urine from fillies and mares (unless in foal)
  • 100 picograms free testosterone per millilitre in plasma from geldings
Theobromine
  • 2 micrograms theobromine per millilitre in urine or
  • 0.3 microgram theobromine per millilitre in plasma
N.B.: The conjugated substance is the substance that can be liberated from conjugates.

The concentrations listed above have been determined to be the maximum concentration permitted in a specimen taken from any horse.

In terms of Rules 73.4 and Rule 74 the abovementioned substances shall be prohibited / forbidden substances if the concentration found in a specimen exceeds the concentration set out above.