Featured Research

from universities, journals, and other organizations

Assay for pulmonary tuberculosis and rifampicin resistance in adults

Date:
January 22, 2014
Source:
Liverpool School of Tropical Medicine
Summary:
A second systematic review of a diagnostic test for tuberculosis (TB) endorsed by the World Health Organization (WHO), has confirmed the accuracy of the test. The updated review assesses the accuracy of Xpert MTB/RIF, and finds that Xpert MTB/RIF is more accurate than smear microscopy for diagnosing TB and also accurate for detecting rifampicin resistance.

A second systematic review of a diagnostic test for tuberculosis (TB) endorsed by the World Health Organization (WHO), has confirmed the accuracy of the test.

The updated review assessing the accuracy of Xpert® MTB/RIF includes new studies published since the original Cochrane Review was published in January last year. Led by Karen Steingart, an Editor with the Cochrane Infectious Diseases Group at LSTM, the researchers found that Xpert® MTB/RIF is more accurate than smear microscopy for diagnosing TB and also accurate for detecting rifampicin resistance.

This updated Cochrane Review was one of three WHO reviews commissioned as part of the process to update the policy on the use of Xpert® MTB/RIF. The WHO policy is available at (http://www.stoptb.org/wg/gli/xpert.asp) TB causes tremendous suffering worldwide, especially in low- and middle-income countries. Around 8.6 million people developed the disease for the first time in 2012 and 1.3 million people died. TB can be cured if the disease is diagnosed and properly treated. Being able to detect TB and TB drug resistance is vital for improving health, reducing deaths and decreasing the spread of TB.

Xpert® MTB/RIF is a new test that quickly detects TB and resistance to rifampicin, one of the major drugs for treating the disease. Xpert® MTB/RIF is automated and can detect TB bacteria at low concentrations. In addition, the test does not require expert staff or an advanced laboratory. In contrast, smear microscopy, the most frequently used test for TB detection in resource-constrained settings requires TB bacteria to be present at high concentrations (thousands of bacteria) and does not diagnose drug resistance. Instead TB would have to be grown in a laboratory, which requires time and expert staff. This updated review, involving around 9500 people, analysed data from an additional nine studies alongside the 18 included originally. Most of the studies were performed in low- or middle-income countries. The findings in the updated review are consistent with those reported previously.

The review found that for TB detection, Xpert® MTB/RIF was accurate (it was sensitive (89%), detecting almost all cases; and specific (99%) that is, not registering positive in people who were actually negative).

For rifampicin resistance detection, Xpert® MTB/RIF was accurate with sensitivity at 95% and specificity at 98%. Xpert® MTB/RIF appeared to have similar accuracy in people with and without HIV infection.

Applying the findings of the review to an imaginary group of 1000 people who go to their doctor with symptoms, but where only 100 of them (10%) actually have TB, Xpert® MTB/RIF would diagnose 88 cases and miss 12, whereas smear microscopy would diagnose 65 cases and miss 35 cases.

Managing Editor of the Cochrane Infectious Diseases Group, Anne-Marie Stephani said: "Given the large number of studies that have assessed the accuracy of Xpert® MTB/RIF, the WHO Global TB Programme commissioned a review to summarize the evidence. This updated review, like the original, shows that Xpert® MTB/RIF is accurate for diagnosing TB and detecting rifampicin resistance, an indicator of multidrug-resistant TB. Xpert® MTB/RIF may be useful in many countries, particularly in low- and middle-income countries where TB is prevalent, as it does not require advanced laboratory facilities or expert staff." She added, "The tests are expensive, so current research evaluating the use of Xpert® MTB/RIF in TB programmes in high TB burden settings will help evaluate how this investment may help start treatment promptly and improve patient health."


Story Source:

The above story is based on materials provided by Liverpool School of Tropical Medicine. Note: Materials may be edited for content and length.


Journal Reference:

  1. Karen R Steingart, Ian Schiller, David J Horne, Madhukar Pai, Catharina C Boehme, Nandini Dendukuri. Xpert® MTB/RIF assay for pulmonary tuberculosis and rifampicin resistance in adults. The Cochrane Review, January 2014 DOI: 10.1002/14651858.CD009593.pub3

Cite This Page:

Liverpool School of Tropical Medicine. "Assay for pulmonary tuberculosis and rifampicin resistance in adults." ScienceDaily. ScienceDaily, 22 January 2014. <www.sciencedaily.com/releases/2014/01/140122091449.htm>.
Liverpool School of Tropical Medicine. (2014, January 22). Assay for pulmonary tuberculosis and rifampicin resistance in adults. ScienceDaily. Retrieved April 20, 2014 from www.sciencedaily.com/releases/2014/01/140122091449.htm
Liverpool School of Tropical Medicine. "Assay for pulmonary tuberculosis and rifampicin resistance in adults." ScienceDaily. www.sciencedaily.com/releases/2014/01/140122091449.htm (accessed April 20, 2014).

Share This



More Health & Medicine News

Sunday, April 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Nine-Month-Old Baby Can't Open His Mouth

Nine-Month-Old Baby Can't Open His Mouth

Newsy (Apr. 19, 2014) — Nine-month-old Wyatt Scott was born with a rare disorder called congenital trismus, which prevents him from opening his mouth. Video provided by Newsy
Powered by NewsLook.com
'Holy Grail' Of Weight Loss? New Find Could Be It

'Holy Grail' Of Weight Loss? New Find Could Be It

Newsy (Apr. 18, 2014) — In a potential breakthrough for future obesity treatments, scientists have used MRI scans to pinpoint brown fat in a living adult for the first time. Video provided by Newsy
Powered by NewsLook.com
Little Progress Made In Fighting Food Poisoning, CDC Says

Little Progress Made In Fighting Food Poisoning, CDC Says

Newsy (Apr. 18, 2014) — A new report shows rates of two foodborne infections increased in the U.S. in recent years, while salmonella actually dropped 9 percent. Video provided by Newsy
Powered by NewsLook.com
Scientists Create Stem Cells From Adult Skin Cells

Scientists Create Stem Cells From Adult Skin Cells

Newsy (Apr. 17, 2014) — The breakthrough could mean a cure for some serious diseases and even the possibility of human cloning, but it's all still a way off. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins