Rory McIlroy has received the results of recent tests and it doesn’t sound too encouraging for the reigning U.S. Open champion.

McIlroy attended a Dubai hospital on Monday and soon after arriving in the UAE from Hong Kong where he captured the UBS Hong Kong Open title.

The 22-year old picked-up a stomach virus while recently competing in a number of events in China.

And while McIlroy has been diagnosed with a lower than normal white blood cell count after his first visit to the hospital during the week before contesting the Mission Hills World Cup, he has now been advised his is suffering platelets that are irregularly shaped fragments in the blood cells.

Rory McIlroy on route to a 66 on day one of the Dubai World Golf Championship. (Photo - Fran Caffrey/www.golffile.ie)

According to Wikipedia the average lifespan of a platelet is normally just 5 to 9 days.

But if the number of platelets is too low, excessive bleeding can occur.

However, if the number of platelets is too high, blood clots can form thrombosis, which may obstruct blood vessels and result in such events as a stroke, pulmonary embolism or a blockage of blood vessels to other parts of the body, such as the extremities of the arms or legs.

A source close to McIlroy indicated the same Dubai doctor who has now treated McIlroy twice will again see him tomorrow night (Saturday) to advise what course of action McIlroy should take.

“Rory is not unwell but he is serioulsy run down,” he said.

“He’s been told not to practice and to hydrate as much as he can and stay indoors when possible.

“We’ve told the Thailand organisers, they know he’s been sick for a few weeks. He wants to play there but I think he’ll make a decision tomorrow night

“The doctors are saying it’s exhaustion, him being run down. The blood count obviously affects his energy levels in a big way.”

While McIlroy struggles with his health he showed no signs of any fatigue in recorded just 26 putts, including 10 one putts during his opening Dubai World Championship round of 66.

The young Ulsterman knows he needs to win in Dubai and for Race to Dubai rival Luke Donald to finish in a tie for ninth with at least two players to be crowned Europe’s number one golfer for 2011.

“The doctors have told Rory not to practice at all and not to go to the gym,” added the source.

“He’s fine but he just needs to conserve energy.

“It’s a virus and he needs time off. They don’t know where he picked it up but it’s one of those that stays dormant for a couple of weeks and then just kind of flares up.”

“Rory’s okay generally as long as he takes the advice of the doctors. He can’t avoid being in the sun for six hours a day playing golf, as long as he then stays indoors and keeps his energy levels up.

“Rory said as long as he gets a good night’s sleep he feels fine in the morning but then he goes out and plays and within an hour of finishing his blood sugar levels go down and he has to go and rest.

“The other problem is when you are run down like that you’re more vulnerable to illness … so if you go to a tropical climate it could be an issue.”

The news throws in doubt McIlroy’s appearance in next week’s Asian Tour season-ending Thailand Golf Championship in Bangkok.

McIlroy is set to join fellow 2011 Major Champions in the $US 1m event that also is being staged as a celebration of the King of Thailand’s 84th birthday.

“We’ve given the Thailand organisers fair warning because we know its important to them he plays there,” also said the source.

“He’s one of the biggest players in the field next week.”