International cycling was plunged into chaos and uncertainty on Saturday when Italian cyclist Marco Pantani was thrown out of the Giro d'Italia after failing a blood test.

Pantani, winner of the GiroTour de France double last year and in a commanding overall lead in this year's Giro, was disqualified after a blood test registered a 52 per cent haemocrit level, two per cent above the 50 per cent maximum permitted by international cycling's governing body, the Union Cycliste Internationale (UCI).

The haemocrit tests were introduced by the UCI two years ago both to safeguard riders' health and to act as a check against the use of EPO, the banned substance at the heart of the doping scandal which marred last summer's Tour de France, resulting in the disqualification of the Festina team captained by French cycling idol, Richard Virenque.

In layman's terms, the haemocrit test provides a reading of an athlete's red blood cell level, quantifying those blood cells which absorb and convert oxygen into raw athletic power and energy. If an athlete's reading is over 50 per cent, he could face serious health risks while at the same time prove capable of a significantly enhanced performance.

Saturday's test on Marco Pantani was carried out early on the morning in Madonna di Campiglio, just as Pantani was preparing to take a commanding lead into the penultimate day of the Giro, which finished in Milan yesterday (won by Ivan Gotti). Saturday's test was one of a number of random tests carried out throughout the Giro by the UCI, whose President Hein Verbruggen commented: "This is the toughest sport there is and it's has become very commercial. Those factors bring pressure so obviously there is more doping in cycling than any other sport.

"Today was a dramatic day for the Giro and for cycling. . . however, this is not doping in Marco Pantani's case. This is only the health checks that we carry out every day. When we introduced these tests two years ago, we wanted a limit of 53 per cent not 50 per cent, because we know levels can change."

Pantani's dramatic and controversial disqualification prompted anger and outrage from Italian sports fans who have come to regard "the Pirate" as nothing less than a national sporting icon after his splendid Giro-Tour double of last season. Pantani's superlative mountain-climbing abilities, as well as the fact that last season's triumphs all came in the wake of a serious leg injury that kept him out of cycling for nearly two years, have further endeared him to cycling fans worldwide.

In the immediate wake of his disqualification, cycling divided into two camps with some claiming he was the victim of an inaccurate test and with others suggesting he was guilty of doping. Giorgio Squinzi, boss of Italian team Mapei, commented: "At this stage of the Giro (after 20 stages and more than 3,000 kilometres), my riders' haemocrit levels are, on average, down five points. If somebody registers a 52 per cent level. . . then you can draw your own conclusions"

Jean-Marie Leblanc, boss of the Tour de France, appeared to agree, saying: "I'm very sad for cycling. It proves there are still riders and doctors who have not understood we must get rid of old habits".

Roberto Rempi, doctor for Pantani's Mercatone-Uno Bianchi team, denied that his athlete had taken any performance-enhancing substance, saying: "A change of temperature from heat to cold in the last two days may have affected his level. In the mountains, riders drink less and this can dry out the body and that could make a difference".

The Mercatone team doctor's theory was partly borne out when Pantani, on team orders, repeated the haemocrit test on Saturday afternoon, registering a 48 per cent level, well within the permitted limit. Sports medical opinion, however, suggests that reliable haemocrit tests can be carried out only in the morning.

As for Pantani himself, his initial reaction to his disqualification was to smash a hotel room window in rage and frustration.

With his hand still bandaged, Pantani later paused on the steps of his hotel in Madonna di Campiglio before driving away from the Giro, hinting to reporters that he might now retire from professional cycling.

"There is something strange about all of this. . . I had already been tested twice in the Giro, when I already had the race leader's pink jersey and both times the reading was 46 per cent. . . In the past, I've come back from terrible accidents but this time I'm morally destroyed, this time I've touched the bottom," Pantani said.