Key messages

• Xpert MTB/RIF Ultra is a rapid test that probably reduces the time taken to diagnose tuberculosis (TB) and the time from diagnosis to starting treatment.

• Using Xpert MTB/RIF Ultra does not reduce deaths from any cause occurring within 18 months.

• The studies in this review did not measure whether rapid tests improve recovery from TB (cure).

What is tuberculosis?

Tuberculosis (TB) is a serious bacterial infection that primarily affects the lungs. TB causes symptoms such as cough, fever, and weight loss. It can also spread to other parts of the body. Children, especially under-fives, are more vulnerable and may develop mild to severe forms of the disease. TB affects many people each year, and is largely curable, though there is a risk of death if standard treatments do not work. Drug-resistant TB is a type of TB that is harder to treat because it does not respond to common medicines.

Why are rapid tests being used?

Traditional diagnostic methods for TB, such as smear microscopy and culture, use the examination of samples under a microscope (an optical instrument that uses a lens to magnify the bacteria) or grow bacteria in a laboratory. A newer type of test known as a molecular test (or 'nucleic acid amplification test') magnifies genetic material in a sample of bodily fluid (e.g. phelgm (saliva)) many times to detect if TB bacteria are present. Some of the molecular tests, such as Xpert MTB/RIF Ultra, can also detect resistance to rifampicin, which is a widely used TB medicine. The molecular tests have been proposed to detect TB more quickly and accurately. This may help patients receive appropriate treatment more quickly.

There are various types of rapid molecular TB tests, which differ in how they are performed and where they are used. Some are conducted in laboratories, whereas others are used in clinics or at the point of care. The World Health Organization (WHO) has categorised the tests into three classes, which they have called laboratory-based automated tests (e.g. Xpert MTB/RIF Ultra, Truenat MTB-RIF Dx, and Truenat MTB Plus), manual laboratory tests (e.g. TB-LAMP), and moderately complex automated tests (e.g. FluoroType XDR-TB). Although health workers generally decide which test to use, patients in private clinics may be able to choose from the test options available.

What did we want to find out?

We wanted to find out whether rapid TB tests affect health outcomes, including death, recovery (cure), discontinuation of treatment, and time taken to diagnose TB and to start treatment.

What did we do?

We searched for evidence from studies known as 'clinical trials' that compared rapid TB tests with traditional methods of testing for TB, like smear microscopy and culture. We summarised the findings and made a judgement about the reliability of the results, based on how the studies were designed and the number of people who took part.

What were the main results of the review?

We identified two clinical trials from three reports published between 2021 and 2024. The two trials involved 11,228 adults being tested for TB. Most participants were from Uganda (a low-income country), and a smaller number were from South Africa (an upper-middle-income country). No information was available on cure rates.

Although our review focused on rapid TB tests in general, all available evidence came from two trials that both evaluated the Xpert MTB/RIF Ultra test. This test did not reduce deaths from any cause at six months or18 months. However, it probably sped up the process of diagnosing TB and starting treatment when compared to traditional testing methods. People tested with Xpert MTB/RIF Ultra were more likely to stop treatment than those tested with smear microscopy. The studies did not measure whether the rapid TB tests improved recovery.

What were the limitations of the evidence?

We found evidence only for the Xpert MTB/RIF Ultra test and not for any other rapid TB test. None of the studies reported how these tests affected patient recovery. All the included studies focused on adults, so it is unclear whether the findings apply to children and adolescents. The studies also used different statistical methods to report time to diagnosis and treatment, making it difficult to compare their results. We rated our confidence in the evidence as moderate because the largest trial did not clearly describe how it measured or planned to analyse the time taken to diagnose TB and the time taken to start treatment.

How up to date is this evidence?

The evidence is based on searches of medical literature run up to 21 January 2025.