A British company says it has developed a blood test for the human form of BSE.
The test has been trialed on two patients
London-based Microsens says the test has so far been used on two people suspected of having vCJD.
It found signs of the disease in one patient, who still shows symptoms. But no signs were found in the second patient and she has since recovered.
Presenting their findings at a conference in Paris, scientists said it could enable doctors to identify those with vCJD for the first time.
It comes just days after a study suggested that as many as 3,800 Britons could be vCJD carriers.
The figure was much higher than previous estimates and appeared to contradict claims that the disease may have peaked.
To date, 141 people have died from vCJD in the UK since it emerged in 1995.
At its peak in 2000, the disease killed 28 people. That dropped to 17 in 2002 and 18 last year. So far this year, two people have died from vCJD.
This has led to speculation that the worst may be over. However, the lack of a test to diagnose the disease means scientists simply do not know.
At the moment, the disease can only be confirmed with post mortem tests on the brain.
Scientists at Microsens believe their blood test could provide the answer.
The Seprion test was originally developed for use in post mortems. It was designed to pick up the rogue prion that is believed to cause vCJD in the brain.
However, tests on animals suggested it could also pick up signs of this prion in blood.
That led to the tests on two patients who were suspected of having vCJD.
"We got a very high reading from one of the patients, while the other came back negative," Microsens chief executive Dr Christopher Stanley told BBC News Online.
"The first patient continues to show signs of the disease while the second patient has since recovered. She was wrongly diagnosed."
The company is now planning to carry out further tests on people suspected of having vCJD. However, it stressed that it was still early stages.
"More resources and development are required before a blood test is a reality," said Stuart Wilson, the company's chief scientific officer.
Microsens hopes it test could be used to screen donated blood for the disease, reducing any risk of vCJD being passed on through blood transfusion.
The UK government has already banned anyone who received a blood transfusion after 1980 from donating blood. It followed reports that one man may have died after receiving infected blood.
The Department of Health has held talks with Microsens.
"The Department of Health met with Microsens last year to discuss the test under development," a spokesman said.
"This is important research in progress and we look forward to studying the company's preliminary results.
"There is currently no way of telling how many people may be incubating vCJD nor to test whether instruments or blood donations pose a risk.
"But researchers from the public and private sectors across the UK and Europe are using a variety of novel approaches towards developing diagnostic tests for human and animal health."
One of those working on a possible test is Dr Chris Pomfrett, a neurophysiologist at Manchester Royal Infirmary. He has developed an electrocardiogram system used in heart monitoring which he believes can spot early signs of the disease.
The test was developed with £112,000 of government money. Tests on animals suggest it does work. However, Dr Pomfrett has been unable to get access to patients with the disease to see if it works on humans.