An alkalinising agent is any substance that may elevate a horse's Total Carbon Dioxide (TCO2) levels when administered by any means, and thus, no person shall administer an alkalinising agent to a horse on race day. 

Prohibited alkalinising agents include substances containing bicarbonates, citrates, succinates, acetates, propionates, maleates, lactates, alkaline water, and trometamol (THAM, Tris Buffer, or Tromethamine), as well as products marketed as urinary alkalinisers, neutralising agents, and lactic acid buffers. Alkalinising agents in commercial feeds and balanced electrolyte supplements, when used according to the manufacturer’s recommendations, have a negligible effect on TCO2 levels. 

The purpose of conducting TCO2 analysis on a race day is to limit the potential unfair advantage of increased blood alkalinity on performance, which is internationally acknowledged. Several factors can elevate TCO2 concentrations in horses, including dehydration, supplements, medications (alkalinising agents), feed, electrolytes and salts, ambient environment, and the horse's clinical physiology. The effects of transport and excitement have not been extensively studied locally or internationally. The NHA as a member of the IFHA accepts the international threshold as being reliable and robust. 

A TCO2 concentration in the blood above the threshold for a horse presented to race constitutes prima facie evidence of alkalinisation (regardless of the means or methodology by which the elevated levels were facilitated), or the use or administration of an alkalinising agent and will result in the horse’s withdrawal from the race.

PROCEDURE FOR TOTAL CARBON DIOXIDE (TCO2) ANALYSIS ON RACE DAY 

The following SPECIMEN collection procedure for TCO2 ANALYSIS will apply on race day: 

1. TRAINERS will, prior thereto, be notified of the HORSES selected for pre-race TCO2 testing and ANALYSIS. 
2. A blood SPECIMEN will be collected from each selected HORSE approximately 60 minutes prior to the published RACE time. Immediate ANALYSIS will be performed by means of an NHA approved handheld blood gas analyser “the first test”.
3. Where such ANALYSIS shows that a HORSE has a TCO2 concentration of more than 36 mmol/L, a second blood SPECIMEN “the second test” will be collected, a minimum of 10 minutes after the first test.
4. If the TCO2 concentration of the second blood SPECIMEN is more than 38 mmol/L, the STEWARDS shall withdraw the HORSE from the RACE and detain the HORSE for additional SPECIMEN collection.
5. Under these circumstances, a third blood SPECIMEN will be collected a minimum of 30 minutes after the second test.
6. The STEWARD/S may, at their sole discretion, instruct a SPECIMEN COLLECTOR to subsequently collect further SPECIMENS from the HORSE, for inter alia analytical testing of all PROHIBITED SUBSTANCES.
7. The STEWARD/S will notify the race day commentator of any HORSE which is passed to run, which underwent a second test.

As per Rule 75.3.2, if the taking of a SPECIMEN from that HORSE is refused by the TRAINER and/or the PERSON in control of such HORSE, then that HORSE shall be withdrawn from the RACE in question. 

In the interests of horse welfare and racing integrity, the NHA may elect to additionally monitor the use of race day medication by means of pre- and post-race specimen collection of any horse presented to race. 

Amended 01/10/2024