Warnie: my dog ate my homework and mummy said it was OK to take them ...

When I was in school and the days were long and dull I would skip school and get my mother to write a note explaining that I was suffering from some strange ailment and had to be excused for the day. Unfortunately, even the more obtuse teachers would see through the charade and determine it was a con.

Warnie, the sports drug regulators are sharper and more focussed than you give them credit for. The stakes are high; your career is on the line. And the practices are simple; don't put anything in your mouth unless you know what it is.

The Australian Sports Drug Agency (ASDA) has been running an extensive programme of testing and teaching aimed at making athletes aware and auditing that awareness through drug testing. Now that Warnie's positive has been confirmed there is no chance of a laboratory mistake.

ASDA have done a remarkable job in keeping Australian sports drug-free. John Mendoza (CEO of ASDA) has just stated that they target athletes whose performance is remarkable or their weight loss is excessive. Taken on face value, and if we assume Warnie is honest, we could assume that he felt as though he would not be unduly targetted because what he has done with regard his body shape has been through diligent exercise. However ...

Let's examine the whys and wherefores of Warnie's case. Shane Warne would have been approached by a testing officer and asked to provide a sample, which would have been separated into two samples marked A and B. Such samples are coded with identical numbers and have the world's best tamper-proof seals. In the lab the A sample would have been opened under controlled conditions of temperature, humidity and in a contamination-free environment and a suite of chemicals determined using a variety of analysis techniques (the laboratory holds International Olympic Committee accreditation). Upon determination of a problem measurement the sample is likely repeated and then a positive would have been declared to ASDA. The laboratory has no idea of who the individual is, only that it was a sample from a cricketer (different sports are tested for different chemicals).

ASDA then had the responsibility to approach both Shane Warne and the governing body. (The ACB in this case. However, ASDA often tells the athlete only and gives them the chance to declare themselves - perhaps this is an honesty test?) What occurs next is the media circus we have seen when the athlete or governing body comes forward.

The B sample was scheduled to be opened in the athlete's presence, or in the presence of their representative (this happened on Valentine's Day but is certainly not a romantic operation). This sample went through the same rigorous testing as the A sample and, as we have all heard, was declared positive for diuretics.

The detailed chemistry of diuretics is complex and uninteresting. However, in a nutshell diuretics are substances which aid the body in expelling liquids. There are many examples of diuretics in society. In fact, tea is a diuretic. Diuretics are a useful chemical when used appropriately. They assist in the removal of excess fluid from the body, which has an advantage of lowering blood pressure. This is one of the dangers of misuse. In a healthy individual the lowering of blood pressure is not a good occurrence, as it will result in the heart having to work harder to ensure that oxygen reaches the extremities. This is why people feel dizzy with low blood pressure. When a person has low blood pressure and they exercise it exacerbates the situation by putting additional strain on the heart and increases the likelihood of cardiac failure by an order of magnitude.

In the case of someone who has recently had an injury and just started to recover there is a likelihood that the individual would feel pressure in their joint and think it is fluid build up - especially if they had a limited knowledge of physiology. If this were compound by arguably the most trusted person in that individual's life informing them that they use fluid tablets and you will be OK if you use them then the decision is made - "Why not? It's not like I am taking steroids or anything!"

A drug cheat can use diuretics to mask, through speeding their expulsion, steroids in urine. (The term 'mask' is something of a misnomer, it implies that the diuretics sit in front of the real performance enhancer and hide their presence when viewed on some machine that spits out answers). A full-blown serious drug cheat would have been advised to drink mountains of liquid while on the diuretics, making his body acceptably hydrated.

If Warnie was a drug cheat his logic may be that he was taking steroids to speed his recovery from the recent dislocated shoulder. Taking the diuretics would expel the unabsorbed steroids rapidly and make detection extremely difficult.

This raises an interesting point: If Warnie took the diuretics to remove fluid from his body because he felt bloated or one of his joints was swollen, he would have realised that too much water in his system was bad. Hence, video footage of the first one-day final may be revealing if it shows Warnie not partaking in the drinks break as vigorously as the others. However, if it showed him drinking like a fish and running off to relieve himself every few minutes, then he was probably trying to flush and re-hydrate.