The recent decision by the Ministry of Health and Family Welfare to ban the manufacture, sale, distribution and use of serological (blood) test kits for diagnosing active tuberculosis — both pulmonary and extra-pulmonary — is significant. The blood test diagnoses active TB based on antibody response. The decision does not come as a surprise. In fact, the question was not whether the government would act but how soon it would ban it. In July last year, the World Health Organisation had for the first time issued an “explicit negative policy recommendation” against a practice used in TB care. India’s Revised National Tuberculosis Control Programme also endorsed WHO’s advice. It is unfortunate that the world health body had to step in to put an end to a test that has become widely available in many developing countries despite not being recommended by any regulatory agency. “A blood test for diagnosing active TB disease is bad practice,” the WHO stated in its July communiqué. The reason it came out strongly against the “diagnostic tool” is that the test produces very unreliable results. According to a 2008 WHO report, none of 19 commercially available rapid serological tests studied “performed well enough to replace [sputum] microscopy.” The organisation found that the tests provide “inconsistent and imprecise” results due to their inferior sensitivity and specificity. Unlike in the case of HIV and other diseases, detecting antibody response in people with active TB is difficult and hence unreliable as many factors can cause the response.
According to an August 2011 paper in PLoS Medicine, the blood test, if used in place of sputum microscopy for a year, will be able to diagnose 14,000 more active TB cases but will end up misdiagnosing more than 121,000 people as suffering from the disease (false positive cases). The antibody test is also prohibitively expensive. Every year in India, about 1.5 million serological tests are done at a cost of $15 million. As a result, a staggering number of people end up being wrongly diagnosed and unnecessarily medicated every year. The direct fallout of unnecessary medication is the increased chances of people developing acquired drug resistance, thus further complicating and compromising TB care. But imposing a ban is just the first step towards rooting out the malaise. Since implementing the ban will be a tall order, there is a need for increasing awareness level among the public. Simultaneously, the government should quickly complete the pilot testing of the WHO recommended Xpert MTB/RIF molecular test and make it widely available. Only the availability of a superior alternative can solve the problem.
Keywords: WHO, tuberculosis, serological test kits, TB diagnosis, TB antibody tests
When was the ban announced? Private labs are still running the tests and making money, an ignorant doctors are still utilising these tests and diagnosing TB while treating patients unnecessarily for TB. The circular should be made public by printing it in newspapers.
sputum examination is only diagnostic for pulmonary T.B., but for extrapulmonary , military variants serological tests are still an useful aid. But the problem is which to opt , T.B-PCR is highly sensitive and specific but is costly and limited available , also the prevalence of disease downplays its judicious usefulness. Hence now is a need of protocol which must define stratigical employment of battery of available test for a particular stage and if possible facility of PCR in atleast all CHC and tertiary hospitals.
excellent lines on the serological tests and impact has been shown up very clearly . Remedies are presented quite nicely from all the WHO ref.
Ministry of Health & family welfare has taken a decision is good But certain things are quite important for treating the disease like tuberculosis.As per the the TB is concerned it requires diagnosis sometimes difficult and long course(min 6-7 months) of treatment.what is problem of the disease in the country like India is poor accessibility of health care facilities which include diagnostic modalities,expertise doctors and patient indifferent attitude towards govt health system for which reason private companies are coming out to manufacture different aiding diagnostic kits make popularize among physicians as well to the common people.Reason behind TB to develop resistance is patient compliance which is single most important factor to develop resistance.Second we may not know the drug potency time to time.Third short gun therapy for Empirical.Ensuring ban Govt has to address the actual problems in peripheral sector where 70% of population harbour the disease.
For a nation that has championed the treatment of another fatal disease known as Polio, the ban has been a bit late. The last thing we want is a TB outbreak. The delay in banning the unfortunate practice was just an invitation to the above mentioned calamity. In such situations there should be quick decision making so that we do not cry foul at a later stage.
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