THE DEPARTMENT of Health said last night that it had every confidence in the Aids virus antibody tests used in Britain, following claims by Australian scientists that some testing is unreliable, and does not show if a person is infected with HIV or not.

A spokesman said that government scientists had recently undertaken a review of the tests that had confirmed their 'state of the art' accuracy. Blood samples that had tested positive for HIV antibodies were subjected to PCR (polymerase chain reaction), a highly sensitive technique to show the presence of minute quantities of viral genetic material. There was an 'extremely good correlation' between the positive blood and the presence of virus, the spokesman said.

'We take the issue of test reliability very seriously, and there is regular quality assurance carried out in this area. We have no reason to suspect that the test is unreliable, and that large numbers of people are testing positive when they are not. A positive report is not issued on the strength of one test, but at least two different tests,' he added.

A spokeswoman for the Public Health Laboratory Service, which collates national test results and carried out the review, said the Australian claims about the tests which appear in the Sunday Times are not relevant to this country. 'Because we have adopted a 'belt and braces' approach to testing and carry out more than one confirmatory test, we are confident that no one has falsely been told they are HIV positive,' she said.

The report says that inaccurate testing in Africa may be responsible for vastly inflated figures of those infected, and that uninfected people with malaria and other diseases, also give a positive result. Malaria as a cause of spurious results was a problem in the mid-1980s but not with the more sensitive tests used today.

The report is the latest in a series of Sunday Times articles supporting the views of a small number of scientists who say HIV does not cause Aids, and that heterosexual Aids is a myth.