Researchers at Glasgow’s Southern General Hospital are currently evaluating the effectiveness of two new blood tests for TB to determine if the tests should be used in screening for latent TB infections in Scotland. Germany, France, and Ireland have successfully used one of the blood tests, QuantiFERON-TB Gold, to drive down the number of new cases of TB.
TB incidence has increased in Scotland by 25 percent over the last 10 years. Health Protection Scotland reported 455 new cases in 2011. New TB cases occur primarily among immigrants from areas like India, Pakistan, and African countries, where there is a high prevalence of TB. Most of the immigrants who develop TB reach Scotland with latent infections that cannot be detected by the chest X-rays administered upon arrival. Sarah Whitehead, laboratory lead for TB in Glasgow, stated that about 10 percent of latent TB infections develop into active TB. For the last 100 years, the only method for detecting latent TB was a skin test that required monitoring to determine a positive response. The skin test has not been used routinely in the United Kingdom.
Based on the outcomes of the blood test evaluations, Glasgow public health agencies are considering a pilot study in which general practitioners invite immigrants with high risk of TB to participate in blood test screenings at Glasgow Royal Infirmary. Whitehead stated that the UK TB Task Force believes the increase in TB among immigrant populations does not constitute a public health threat to the native population of Scotland.