Health Protection Scotland has requested, via local authorities and health boards, that schools infected with swine flu volunteer to take part in the tests.

The proposals come as the number of school-age children infected with swine flu continues to rise, with hospital admission rates of the 5-14 group also climbing.

However, the education establishment has so far rejected the approach, and no school has yet approved the clinical research.

Dr Jim McMenamin, consultant epidemiologist at Health Protection Scotland, said that a blood-based investigation would confirm whether young people, those most at risk from contracting the virus, were naturally building up a resistance to it.

But Dr McMenamin added that there was “tension” between public health bodies and educationalists over the proposal, which could involve entire year groups of pupils.

He told a swine flu symposium at the Royal College of Physicians and Surgeons in Glasgow yesterday: “It would be fair to say that it is a difficult area because there is no immediate benefit to any child to give a sample. The benefit will be to public health in a broader sense.”

The symposium heard that around eight schools across Scotland had experienced increased absence rates since the start of the new term, although swine flu was not thought to be responsible for all of them.

The Queen called off a planned visit to the exclusive Gordonstoun School in Moray earlier this month after it emerged that more than 100 pupils from its 600-strong roll were off sick following a swine flu outbreak.

Dr McMenamin stressed that the blood tests would not be compulsory and would only be requested of secondary school pupils, adding that only one school would have to take part in Scotland to contribute to an effective UK-wide analysis of the pandemic’s behaviour.

He told The Herald: “Most investigations into swine flu use throat swabs. If you are able to do blood tests, it could help establish if that person has developed an immunity to the virus.

“It would be a public health investigation and it would help us plan what the effect is going to be across the whole country. But the problem is that as a headteacher, as a parent, would you be prepared to have your child give a blood sample?

“It would only apply for young people above a certain age and it is something that would be done under consent. There would be no obligation to do this.”

Dr McMenamin told the symposium that the current swine flu pandemic was an “age-driven” phenomenon with flu infection rates among five to 14-year-olds already at the level normally seen during the winter period.

It was yet to be confirmed if the start of the new school term had accelerated the spread of infection, but it was normal for GPs to see a higher number of young people with flu symptoms at this time of year.

“This is the pattern we see every year. Whether it turns out to be something of greater magnitude is something we won’t know until we get there,” Dr McMenamin said.

Dr Harry Burns, Chief Medical Officer for Scotland, told the assembly of clinicians that swine flu was now the most common reason for a young person being admitted to hospital.

He said that, overall, he expected hospital admissions for swine flu to rise in the next two weeks.

A spokeswoman for Education and Lifelong Learning at the Scottish Government said: “If an appropriate school is identified, and subject to the agreement of schools, parents of children and the local authority, the Scottish Government would have no problem with a study of this nature being taken forward.”