Police are waiting to see if the blood samples match Madeleine's DNA

Police are waiting today for the results of tests carried out on traces of blood recovered from Madeleine McCann's holiday home.

Samples arrived yesterday at a top UK forensic laboratory in a bid to establish if the evidence matched the DNA of the missing four-year-old.

The traces, found on the wall of the Algarve apartment, were only uncovered this week - more than three months after the British girl disappeared.

It is believed a specially-trained sniffer dog, brought in by British detectives, located the tiny traces despite attempts to wash them off.

Scientists are hoping to extract DNA from the sample to cross-reference against an example obtained from a toothbrush or hairbrush used by Madeleine

A Forensic Science Service spokesman confirmed that the evidence had been received, but declined to comment further on a "live case".

It is unclear when the results of the new tests will be known.

Friends of the family said they were disgusted at what they said was a smear campaign against them.

Detectives will be desperate for a concrete forensic lead in the search after tests on a milkshake bottle used by a girl who looked like Madeleine in Belgium proved inconclusive.

A DNA sample taken from a restaurant in Tongeren, close to the Dutch border, where a woman reported seeing Madeleine with a suspicious couple, was found to be that of a man.

But investigators said the findings did not rule out that Madeleine was present and said they were still hunting the couple's black Volvo car.

Spokeswoman Katja Vandoren said: "This does not mean that Madeleine's presence is ruled out.

"The possibility exists that the bottle was finished by the man who was with the little girl present. We continue to examine all useful tips."