Molecular tests for TB
Global rollout of rapid molecular tests for tuberculosis over the last 12 years

Date:
April 26, 2022
Source:
Liverpool School of Tropical Medicine
Summary:
A potential game-changer in the tuberculosis epidemic was how
the tuberculosis community viewed rapid molecular tests for
tuberculosis and tuberculosis drug resistance. This was 12 years
ago, with the launch of Xpert MTB/RIF, which gives results in
less than two hours, simultaneously diagnosing tuberculosis and
testing if the bacteria have rifampicin resistance, a type of
drug-resistant tuberculosis. Multidrug-resistant tuberculosis is
caused by resistance to at least both rifampicin and isoniazid,
the two most effective first-line drugs used to treat tuberculosis.



FULL STORY ==========================================================================
A potential game-changer in the tuberculosis epidemic was how the
tuberculosis community viewed rapid molecular tests for tuberculosis and tuberculosis drug resistance. This was 12 years ago, with the launch of
Xpert MTB/RIF, which gives results in less than two hours, simultaneously diagnosing tuberculosis and testing if the bacteria have rifampicin
resistance, a type of drug- resistant tuberculosis. Multidrug-resistant tuberculosis is caused by resistance to at least both rifampicin
and isoniazid, the two most effective first-line drugs used to treat tuberculosis.


==========================================================================
Yet, diagnostic tests only have an impact on health if they are put to use
in a correct and timely manner. To ensure diagnostics are accessible and utilized, we need to understand the views of recipients and providers
who have used these tests, and a new qualitative evidence synthesis
review published by the Cochrane Infectious Diseases Group (CIDG) pulls together all relevant research to date on Xpert MTB/RIF and similar
tests. The authors also wanted to understand the implications of the
review findings on effective implementation and health equity.

Rapid molecular tests have been shown to be accurate in diagnosing
tuberculosis and rifampicin resistance and are recommended by the World
Health Organization as the initial test in people with presumptive tuberculosis, replacing sputum microscopy, a test from the 19th
century. These tests have many benefits, including the fact that they
do not require well-equipped laboratories and skilled personnel, and
can be carried out in community health settings, nearer to where people
live. This is particularly relevant in low- and middle-income countries, settings with a high burden of tuberculosis.

Examining the evidence from 32 included studies, the review author
team identified aspects of these tests that users valued most and
challenges to realizing those values. People with tuberculosis valued an accurate diagnosis (knowing what is wrong with me), avoiding delays, and keeping diagnostic- associated cost low. Similarly, healthcare providers
valued test accuracy and confidence in results (which helps in starting treatment), rapid results, and keeping cost to people seeking a diagnosis
low. In addition, providers valued diversity of sample types (for example, gastric aspirate specimens and stool in children) and ability to detect
drug resistance early. Laboratory professionals appreciated the improved
ease of use compared to microscopy and increased staff satisfaction.

Reported challenges included reluctance to test for tuberculosis owing to stigma or cost concerns; health system inefficiencies such as poor quality
of specimens, difficulty in transporting specimens, lack of sufficient
staff or equipment, increased workload for providers, inefficiencies
in integrating the test into clinic routines and clinicians relying
too much on the test result at expense of their own experience with
diagnosing tuberculosis; as well as implementation processes hampered
by insufficient data about real-life situations, lack of inclusion of
all relevant stakeholders (local decision- makers, providers or people
seeking a diagnosis), and conflicts of interest between donors and people implementing the tests.

"The findings reveal a fundamental paradox between supporting
technological innovations but not in parallel investing in
health system infrastructure strengthening. The view that these
low-complexity diagnostics are a solution to overcome deficiencies
in laboratory infrastructure and lack of skilled professional is
misleading. Implementation of new diagnostic technologies, like those considered in this review, will need to tackle the challenges identified
in this review including weak infrastructure and systems, and insufficient
data on ground level realities prior and during implementation, as well
as problems of conflicts of interest in order to ensure quality care and equitable use of resources." stated Nora Engel, lead author of the review.

The review authors called for future research to examine the implications
of repurposing diagnostic infrastructure and equipment for COVID-19 and
the issue of competition for diagnostic resources more generally.


========================================================================== Story Source: Materials provided by
Liverpool_School_of_Tropical_Medicine. Note: Content may be edited for
style and length.


========================================================================== Journal Reference:
1. Nora Engel, Eleanor A Ochodo, Perpetua Wanjiku Karanja, Bey-Marrie'
Schmidt, Ricky Janssen, Karen R Steingart, Sandy Oliver. Rapid
molecular tests for tuberculosis and tuberculosis drug resistance:
a qualitative evidence synthesis of recipient and provider
views. Cochrane Database of Systematic Reviews, 2022; 2022 (4)
DOI: 10.1002/14651858.CD014877.pub2 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220426153634.htm

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