Controversy grows over use of x-ray for TB screening of immigrants

August 3, 2010

The current U.K. screening scheme for tuberculosis, which targets newly arrived immigrants from countries where TB is endemic, doesn’t work and should be scrapped, say leading specialist doctors in this month’s issue of Thorax.

The current U.K. screening scheme for tuberculosis, which targets newly arrived immigrants from countries where TB is endemic, doesn’t work and should be scrapped, say leading specialist doctors in this month’s issue of Thorax.

The Port of Arrival Scheme, which has operated since 1971, focuses on those wishing to stay in the U.K. for at least six months and arriving from countries with high rates of TB (more than 40 per 100,000 of the population).

It involves offering either a chest x-ray on arrival in the U.K. or referral to a local chest clinic for assessment. But this system is fundamentally flawed, said respiratory specialists Dr. John Moore-Gillon and Professors Peter Davies and Peter Ormerod, as the figures suggest.

Worldwide, TB kills more than a million people every year; more than nine million people develop active disease every year.

Global travel has prompted a sharp rise in U.K. the number of patients with TB. Around 8500 cases of active disease are diagnosed annually in the U.K., more than 70% in people born elsewhere.

“Clearly, current methods of TB screening for new entrants...are not working,” said the authors.

This is largely because there are no standard criteria for who is offered screening and there is often no way of checking whether they turn up to a local clinic, they say.

Furthermore, a TB screen is triggered only by immigration status, not by arrival-irrespective of nationality or British citizenship-from a high-risk country.

And the screen is geared toward picking up active infection, yet it is estimated that a third of the global population has latent TB infection.

“This third would include a high proportion of the over 65s born in the U.K. (and probably many healthcare workers),” the authors write, emphasizing that one in 10 of those with latent infection will progress to active disease.

The screen is also designed to uncover respiratory TB, yet TB in other sites of the body, such as the spine, gut, kidneys, and brain, accounts for almost half (44%) of cases in new arrivals.

The much-touted idea of screening those who plan to come to the U.K. is neither cost- nor clinically effective by itself, the evidence suggests, the authors said. The best option would be for recently arrived immigrants from high-risk countries to be screened in community services, they suggest, although such services are currently overstretched due to increased demand.

The authors ask whether the time has come for new arrivals to be granted a residency permit only on condition they register with a general practitioner for a TB test, as is the case in the Netherlands and Norway.