In this week's BMJ, two groups of public health doctors argue for routine opt-out HIV testing in healthcare settings such as general practice surgeries, accident and emergency departments and hospital wards.
In the first article, Professor Harold Jaffe and colleagues say that a third of people in the UK with HIV do not know they have the virus, yet UK guidelines recommend opt-out testing only for pregnant women and people attending genitourinary (GUM) clinics.
They argue that routine opt-out testing would not only give a more accurate picture of how many people have HIV, but would cut infection rates, lessen the stigma surrounding testing and reduce the number of people being diagnosed in the later stages of HIV.
They point to America where guidelines from the Centres for Disease Control and Prevention now recommend voluntary opt-out testing as the standard of care for people aged 13-64 years, unless the prevalence of HIV is less than 0.1% of the population.
They say "programmes for routine screening have been instituted in emergency departments and urgent care centres at several US hospitals and yielded relatively high rates of previously undiagnosed HIV infection".
About 20,000 UK residents between the ages of 15 and 59 were living with undiagnosed HIV infection in 2005.
Surveys of gay men attending GUM clinics in the same year showed the prevalence of undiagnosed HIV was 3.2%. In women of childbearing age that prevalence was much lower (0.09%), but was highest in women from sub-Saharan Africa (2.4%).
The authors therefore call for surveys to be carried out in areas of known increased HIV prevalence and in facilities that are known to serve people at increased risk of infection. This would provide the necessary data to inform a discussion of expanding opt-out HIV testing.
"In view of the clear advantages of early diagnosis of HIV infection for public and individual health, we believe the effectiveness and feasibility of expanded opt-out testing should be seriously assessed," they conclude.
In the second article, researchers look at the situation in France, where the rate of HIV testing is among the highest in Europe, but 40% of people are still not diagnosed until the disease is advanced, either with AIDS or with a low CD4 cell count.
Therefore, of the estimated 7,000 people newly diagnosed with HIV in France in 2004, 3,000 may have advanced disease.
This has a major impact on death rates and the spread of infection, say Cyrille Delpierre and colleagues. Each year, one fifth of HIV infected patients' deaths were patients who had discovered their infection in the year before their deaths.
While the current policy in France successfully targets at risk groups, they say it fails to reach low risk groups, who tend to be older, mainly men, heterosexual, with a partner and children. Low risk groups are the most likely to test late.
They say late testing could play an important role in the spread of the infection. Studies suggest that if someone knows they are infected they are more likely to use preventative measures, such as using a condom.
Late testing could also be associated with greater costs in hospital care and the management of opportunistic infections. Catching these people earlier could, they say, lead to a reduction of 31% a year in the number of new sexually transmitted infections.
They therefore recommend expanding routine voluntary HIV testing to all primary health care settings.
An accompanying editorial argues that a more precise goal for any changes in policy should be to reduce the average time between infection and diagnosis.