Titled "Tuberculosis: clinical diagnosis and management of tuberculosis, and measures for its prevention and control", the NICE recommendations state that screening for latent TB infection - which has no symptoms and is not infectious but has the potential to develop into TB disease at any time – will include administering the unlicensed Mantoux tuberculin skin test in the first instance and, if the results are positive, conducting a further blood test (also known as an interferon-gamma immunological test) to confirm the accuracy of the skin test. More importantly the guidelines confirm the use of blood tests as the first line diagnostic for latent TB in all immunosuppressed individuals, whatever the cause. This includes HIV infection as well as any drug induced immunosuppression, which may occur in groups such as transplant and arthritis patients.
Additionally the guidelines indicate that the blood tests have a role to play in the diagnosis of TB disease especially in non-pulmonary TB and as a rule-out test in TB suspects.
The NICE recommendations for TB come just after The Centers for Disease Control and Prevention (CDC) in the US advised a simple, one-step blood test be used in all circumstances under which the traditional skin test is currently used, as part of its new TB detection guideline.
Oxford Immunotec Chief Executive Officer, Dr. Peter Wrighton-Smith, said: "We welcome NICE's recognition of blood testing and its important role in the diagnosis of latent TB infection. Blood tests for Mycobacterium tuberculosis offer significant advantages over the tuberculin skin test in terms of accuracy, convenience and reliability and this decision represents a significant step forward in modernising the way TB is managed in England and Wales. In addition, it supports the Government's TB Action Plan, which states accurate TB diagnosis through the use of modern laboratory techniques is essential."
A recent survey conducted by leading research company, IPSOS, reveals the general public agree with the NICE recommendations. Nearly all those surveyed (93%) felt it was important that TB is diagnosed as accurately as possible every time, with around three quarters (76%) believing blood testing should replace the skin test as the standard TB diagnostic tool in the UK.
NICE's inclusion of blood testing is a particularly important outcome for people with weakened immune systems, such as those with HIV, as well as transplant and arthritis patients. Crucially, the T-SPOT.TB test is the first reliable diagnostic tool for detecting TB infection in the immunocompromised. The 115-year-old tuberculin skin test is the oldest diagnostic tool still in use today and is unable to accurately diagnose TB infection, particularly in this patient group.
Last year the UK was forced to replace the original Heaf method of skin testing with the even older Mantoux method (which has been used across other parts of Europe for many years), because the Heaf components were no longer available. The Mantoux technique is technically more difficult to administer and the purified protein derivative which is injected is not licensed in the UK. This change has increased the training needed for the technique and requires additional paperwork as the Mantoux test is not licensed.
Dr Wrighton-Smith commented: "This guideline will raise awareness of the risk that TB poses and we welcome that. It is disappointing however that they fail to recognise the costs that the NHS must bear in re-training healthcare professionals to use the Mantoux technique and the additional work required as a result of it being an unlicensed product. T-SPOT.TB not only offers superior performance in giving accurate results but is also fully licensed in the UK and therefore represents a logical and effective tool in the fight to control TB in this country."
TB disease affects around 7,000 people in the UK each year however up to a further four million people could be infected with latent TB. It is hoped that adequate funding will be provided to ensure the recommended changes outlined in the NICE guideline for TB can be incorporated.
About the NICE Guideline for TB
About Oxford Immunotec (www.oxfordimmunotec.com)
Oxford Immunotec, the T-cell measurement company, is headquartered near Oxford, UK. The Company develops and sells clinical diagnostic products based on its patented T-SPOTTM technology. T-SPOT is a novel platform technology that opens up new ways of diagnosing and monitoring infections by providing a simple and extremely accurate method of studying a person's cellular immune response to an infection. T-SPOT technology can be applied to diagnose and monitor any major disease driven by a T-cell response.
T-SPOT.TB is an in vitro T cell measurement test used for diagnosing TB disease and latent TB infection and the first product from Oxford Immunotec using the T-SPOT technology. The product is extremely robust in that it gives a result every time and offers unrivalled and maintained sensitivity in high risk and immunocompromised patient groups. T-SPOT.TB is approved for sale in Europe and is designed to replace the 115 year old Tuberculin Skin Test. As such it offers a substantially more accurate and effective tool for controlling the spread of TB, addressing a market of £600m.
Unlike the traditional Tuberculin Skin Test, the T-SPOT.TB test incorporates a positive control, allowing the user to distinguish between a genuine negative result and one which is indeterminate (i.e. an inconclusive result) as a result of a technical failure.
In November 2005, Oxford Immunotec's T-SPOT.TB blood test won the prestigious Equinox-sponsored award for the Best Business Proposition at the Medical Futures Innovation Awards.
T-SPOT is a trademark of Oxford Immunotec.
Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
Published on PsychCentral.com. All rights reserved.