NHA LABORATORY
International Screening and Residue Limits and Asian Screening Limits

The National Horseracing Authority wishes to advise that the International Federation of Horseracing Authorities (IFHA) has approved International Screening Limits (ISLs) to be applied in the control of therapeutic substances and also Residue Limits to control certain contaminants and environmental substances. These ISLs and International Residue Limits form part of the International Agreement on Breeding, Racing and Wagering. The NHA, as the South African member of the IFHA, has agreed to adopt selected ISLs. In accordance with this, the NHA is currently applying these in its screening program while employing the IFHA’s definition which is as follows:

“The ISL is the urine or plasma concentration adopted for the screening of a specified therapeutic prohibited substance; it is derived from administration studies followed by a risk analysis consisting of two components: a risk assessment (evaluation of the effect of the substance and factors related to its control) and a risk management (decision step for harmonisation). ISLs and International Residue Limits are harmonised detection limits agreed following input by international consensus and are conveyed by instruction from racing authorities to their laboratories. These limits are simply the detection limits to be used by the laboratories when screening for certain therapeutic substances as instructed by the authorities; they are not international thresholds. When the screening procedure indicates the limit, in either urine or plasma, has been exceeded, all that is required is qualitative confirmatory analysis (usually by mass spectrometry) to confirm the presence or absence of the prohibited substance. Quantification is not required.”

Substance International Screening Limit (nanograms per millilitre in hydrolysed urine) International Screening Limit (nanograms per millilitre in plasma)
Acepromazine 10 e 0.02
Betamethasone 0.2
Bromhexine 200
Butorphanol 1 0.01
Carprofen 100 100
Dantrolene 1 g
Dembrexine 100 5.0
Detomidine 2 f 0.02 h
Dexamethasone 0.2
Diclofenac 50
Dipyrone 1000 a
Eltenac 50
Flunixin 100 1.0
Furosemide 50 0.1
Ipratropium 0.25
Ketoprofen 100
Lidocaine 10 b 0.05
Meclofenamic Acid 250 5.0
Meloxicam 10 1
Mepivacaine 10 c 0.05
Naproxen 250
N-Butylscopolammonium 25 0.05
Romifidine 1
Salbutamol 0.5
Triamcinolone Acetonide 0.5
Vedaprofen 50
 
aControlled by 4-methylaminoantipyrine
bControlled by 3'-hydroxylidocaine
cControlled by 3'-hydroxymepivacaine
dControlled by ambroxol
eControlled by 2-(1-hydroxyethyl)promazine sulphoxide
fControlled by 3'-hydroxydetomidine
gControlled by 5-hydroxydantrolene
hControlled by 3’-Hydroxydetomidine
 
Substance International Residue Limits
Caffeine 50 ng/ml urine
Theophylline 250 ng/ml urine
Morphine* 30 ng/ml urine
Bufotenine 10 µg/ml urine
DMT (N,N-Dimethoxytyramine) 0 µg/ml urine
Hordenine 80 µg/ml urine
Theobromine 2 µg/ml urine
Theobromine 0.3 µg/ml plasma
* Total Morphine, in both free and conjugated forms.



The National Horseracing Authority is a signatory country of the Asian Racing Federation and has decided to adopt Asian Screening Limits (ASLs) for the substances indicated below. The Asian Racing Federation definition is worded as follows: “ASLs are merely harmonised therapeutic substance detection limits adopted by the signatory countries (and conveyed by instruction from racing authorities to their laboratories) for use in the screening of the specified therapeutic substances. The ASLs are NOT international thresholds. When this detection limit is exceeded in the screening process, qualitative confirmatory analysis will be followed to confirm the presence or absence of the prohibited substance. Accurate quantification is NOT REQUIRED for reporting as these therapeutic substances are prohibited by the relevant rules at any levels. ASLs are NOT APPLICABLE to the concurrent detection of a diuretic (for urinary ASLs) or a pharmacologically related medication. Urine and plasma ASLs of the same medication are to be applied INDEPENDENTLY.”

Therapeutic Substances Asian Screening Limits (ASLs)
Methocarbamol
(restricted to single oral or IV treatment of no more than 5 grams)
100 ng/mL in urine
Clenbuterol 0.2 ng/mL in urine
Meloxicam 1 ng/mL in plasma