世卫组织：通过验血诊断活动性结核病易导致误诊误治
2011-07-28 12:23:13   来源：   作者：  评论：0 点击：

世界卫生组织7月20日说，通过验血的方式诊断活动性结核病容易导致误诊误治，该组织因此呼吁各国政府禁止用这一方式诊断活动性结核病。

世卫组织结核病防治司司长马里奥·拉维廖内当天在日内瓦举行的记者会上说，世卫组织及结核病防治专家曾对近百个研究报告进行为期一年的分析，发现在血液中查找结核病抗原或抗体十分困难，验血得到的结果既不准确，也不可靠，用验血结果来诊断活动性结核病容易导致误诊误治。

拉维廖内指出，全球每年约有100万人使用验血的方法来诊断结核病，多集中在缺乏结核病诊断能力的发展中国家。他强调，要确诊结核病，绝不允许用验血来取代现有的微生物检测方式。

拉维廖内还说，提高早期诊断水平可挽救更多结核病患者生命，世卫组织正与其他结核病防治机构合作，寻找更为有效、更为准确的结核病诊断方法。

世卫组织的数据显示，目前全球每年新增结核病患者940万名，每年全球死于结核病的人数至少170万。



生物探索推荐世卫组织原文阅读：

WHO warns against the use of inaccurate blood tests for active tuberculosis
A substandard test with unreliable results
The use of currently available commercial blood (serological) tests to 
diagnose active tuberculosis (TB) often leads to misdiagnosis, 
mistreatment and potential harm to public health, says WHO in a policy 
recommendation issued today. WHO is urging countries to ban the 
inaccurate and unapproved blood tests and instead rely on accurate 
microbiological or molecular tests, as recommended by WHO.

TB can be wrongly diagnosed
http://www.***.com/news/healthcare/article/90782.html
Testing for active TB disease through antibodies or antigens found in 
the blood is extremely difficult. Patients can have different antibody 
responses suggesting that they have active TB even when they do not. 
Antibodies may also develop against other organisms which again could 
wrongly indicate they have active TB. In addition, different organisms 
share the same antigens, making tests results unreliable. These factors 
can result in TB disease not being identified or wrongly diagnosed.

A blood test for diagnosing active TB disease is bad practice

"In the best interests of patients and caregivers in the private and 
public health sectors, WHO is calling for an end to the use of these 
serological tests to diagnose tuberculosis," said Dr Mario Raviglione, 
Director of WHO Stop TB Department. "A blood test for diagnosing active 
TB disease is bad practice. Test results are inconsistent, imprecise and
put patients' lives in danger."

Today's policy recommendation applies to blood tests for active TB. 
Blood tests for inactive TB infection (also known as dormant or latent 
TB) are currently under review by WHO.

New recommendation after 12 months of rigorous analysis

The new recommendation comes after 12 months of rigorous analysis of 
evidence by WHO and global experts. Ninety-four studies were evaluated -
67 for pulmonary tuberculosis (TB in the lungs) and 27 for 
extrapulmonary tuberculosis (TB elsewhere in other organs). Overwhelming
evidence showed that the blood tests produced an unacceptable level of 
wrong results - false-positives or false-negatives - relative to tests 
endorsed by WHO.

Problems of misdiagnosis

The research revealed "low sensitivity" in commercial blood tests which
leads to an unacceptably high number of patients wrongly being given 
the 'all clear' (i.e. a false-negative when in reality they have active 
TB). This can result in the transmission of the disease to others or 
even death from untreated tuberculosis. It also revealed "low 
specificity", which leads to an unacceptably high number of patients 
being wrongly diagnosed with TB (i.e. a false-positive when in reality 
they do not have active TB). Those patients may then undergo unnecessary
treatment, while the real cause of their illness remains undiagnosed, 
which may then also result in premature death.

The inaccurate blood tests are costly

More than a million of these inaccurate blood tests are carried out 
annually to diagnose active TB, often at great financial cost to 
patients. Many patients pay up to US$ 30 per test. There are at least 18
of these blood tests available on the market. Most of these tests are 
manufactured in Europe and North America, even though the blood tests 
are not approved by any recognized regulatory body.

Selling substandard tests with unreliable results

"Blood tests for TB are often targeted at countries with weak 
regulatory mechanisms for diagnostics, where questionable marketing 
incentives can override the welfare of patients," said Dr Karin Weyer, 
Coordinator of TB Diagnostics and Laboratory Strengthening for the WHO 
Stop TB Department. "It's a multi-million dollar business centred on 
selling substandard tests with unreliable results."

This is the first time WHO has issued an explicit "negative" policy 
recommendation against a practice that is widely used in tuberculosis 
care. It underscores the Organization's determination to translate 
strong evidence into clear policy advice to governments.

Tuberculosis kills 1.7 million people every year, and is the major 
killer of people living with HIV. Improving the early and effective 
diagnosis of TB to ensure more lives are saved is a priority action for 
WHO and the international TB community. TB research is currently 
underway to bring better and more rapid tests that are easy to 
administer, effective and accurate.