Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Discordance among commercially-available diagnostics for latent TB infection

09.12.2011
In populations with a low prevalence of tuberculosis (TB), the majority of positives with the three tests commercially available in the U.S for the diagnosis of TB are false positives, according to a new study.

"We compared commercially available tests for latent tuberculosis infection (LTBI) in a diverse population with a low LTBI prevalence," said James Mancuso, MD, DrPH, of the Walter Reed Army Institute of Research Preventive Medicine Residency Program. "Our results suggest that in low-prevalence populations, most positive results obtained with these tests are false positives."

The findings were published online ahead of print publication in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.

The cross-sectional study involved 2,017 military recruits at Fort Jackson, South Carolina, who completed a risk factor questionnaire and underwent testing with the 3 tests: 1) tuberculin skin test (TST), 2) the interferon gamma release assays (IGRAs) QuantiFERON®-TB Gold In-Tube test (QFT-GIT) and 3) the TSPOT® TB test (T-Spot). The Battey Skin Test (BST) was also administered to assess the impact of non-tuberculosis mycobacteria (NTM) reactivity on test discordance.

The specificities of TST, QFT-GIT, and T-Spot were not significantly different. Of 88 subjects with a positive test, 68 (77%) were positive to one test, 10 (11.4%) were positive to two tests, and only 10 (11.4%) were positive to all three tests. Bacille Calmette Guerin vaccination, tuberculosis prevalence in country of birth,and Battey skin test reaction size were associated with TST positive, IGRA negative test discordance, supporting evidence that NTM sensitization can cause false positive TST results. Greater quantitative test results and higher TB risk strata were associated with increased concordance between tests.

"Our data support a high proportion of false positives with any of these three tests in a low- prevalence population," added Dr. Mancuso, "as 77 percent of our subjects had positive results with only one test. Lower quantitative results were associated with a smaller risk for TB exposure and single positive tests, and lower risk for TB exposure was associated with decreasing test agreement."

There were some limitations to the study, including the lack of a gold standard for determining the presence of M. tuberculosis infection and administrative restrictions that resulted in an increased proportion of inadequate blood draws and TST reading times, which were slightly shorter than optimal.

"Low positive predictive value (PPV) is a well-known issue with the TST, and risk stratification is recommended to guide interpretation of the test," concluded Dr. Mancuso. "Our study suggests that risk stratification may also increase the PPV and reduce the number of false positives with the IGRAs. In accordance with the CDC's recommendation, people at minimal risk of TB infection should not be targeted for LTBI testing, regardless of which test is used."

About the American Journal of Respiratory Research and Critical Care Medicine:

With an impact factor of 10.191, the AJRRCM is a peer-reviewed journal published by the American Thoracic Society. It aims to publish the most innovative science and the highest quality reviews, practice guidelines and statements in the pulmonary, critical care and sleep-related fields.

Founded in 1905, the American Thoracic Society is the world's leading medical association dedicated to advancing pulmonary, critical care and sleep medicine. The Society's 15,000 members prevent and fight respiratory disease around the globe through research, education, patient care and advocacy.

Nathaniel Dunford | EurekAlert!
Further information:
http://www.thoracic.org

More articles from Health and Medicine:

nachricht Study tracks inner workings of the brain with new biosensor
16.08.2018 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht Foods of the future
15.08.2018 | Georg-August-Universität Göttingen

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Smallest transistor worldwide switches current with a single atom in solid electrolyte

17.08.2018 | Physics and Astronomy

Robots as Tools and Partners in Rehabilitation

17.08.2018 | Information Technology

Climate Impact Research in Hannover: Small Plants against Large Waves

17.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>