[lettie]

Originally Posted by garinda

How do they work out that figure?

'an estimated 19,700, who remain unaware of their infection and therefore undiagnosed.'

It's incredibly easy to work that out. In certain areas of the country they still do what is known as unlinked anonymous screening (UAS). This started in the 80's in order to give the government an idea of how many people in this country were potentially affected, therefore they could plan the budget for how many they may eventually have to treat. Thousands of blood samples taken at clinics and GP surgeries were sent to local labs to be tested for what they were taken for. Once those tests were done all identifying labels were taken off the blood and it was then sent to another lab and HIV screened. This still goes on in some forms around the country and includes blood taken from infants. It is completely anonymous, the lab, GP's and patients do not know whose blood has been anonymously screened and whose hasn't but it can give the gov't a ballpark figure in order to provide services.

The blood taken from infants blood spot tests (done at 7 days old) may well match up with maternal tests done in pregnancy. The women know about this test and are counselled for it. It is not anonymous and unlinked for the women but the baby's test is. Any known HIV positive mother will have her baby tested at certain intervals to see if it has been transmitted to the baby. By 18 months of age, if the baby is negative then no transmission has occurred. Babies will test positive for the first few weeks of life because they carry maternal antibodies which they discard later. Therefore the infant blood spots do not tell us the number of children affected but the number of mothers. Some women do refuse to be tested in pregnancy because they believe that they are not at risk. We do have about 80-90% uptake of the test now in this country antenatally. Basically anyone who has had unprotected sex (which is how most babies are made) is at risk.