Revolution in TB diagnostics: GeneXpert technology and the role of Partners In Health

In the fight against tuberculosis (TB), rapid and accurate diagnosis is essential. It facilitates timely initiation of treatment, reduces transmission and prevents resistance. Therefore, Cepheid, a subsidiary of Danaher Corporation, developed the GeneXpert system in 2005.

In 2010, the TB-specific version, called Xpert MTB/RIF, was launched. This test was evaluated and recommended by the World Health Organization (WHO). According to the WHO, the development of Xpert MTB/RIF was a “major step” in the diagnosis and detection of resistance.

Since 2012, Partners In Health (PIH) has implemented this technology, starting in Lesotho. Currently, GeneXpert machines are available in eight PIH branches: Haiti, Peru, Malawi, Rwanda, Liberia, Sierra Leone and Kazakhstan, expanding its global reach.

In Peru, the adoption of this diagnostic method has been a significant advance. This molecular system makes it possible to detect TB and its resistance to antibiotics quickly, favoring early and effective treatment for affected patients.

Socios En Salud, through the Global Fund’s TB-HIV Country Project, has donated 12 GeneXpert kits to the public health system in the last year. In addition, it has managed the acquisition of 17 sets of equipment for reference laboratories and health centers in Metropolitan Lima.

However, the efforts do not end here. As we will see below, there is still work to be done globally to make this technology available to the most disadvantaged communities.

How does GeneXpert work and what diseases does it apply to?

PIH specialists define the GeneXpert as a PCR (polymerase chain reaction) machine that operates as a closed system, designed to perform automated cartridge-based testing, a technique considered the quality standard in many diagnostic laboratories.

This technology allows testing to be performed within a few hours: a disease-specific cartridge is simply inserted into the machine, and the machine detects and amplifies the genetic sequences of the virus or bacteria present in the sample (DNA or RNA). In this way, it quickly confirms whether or not a person has the disease.

Unlike traditional PCR tests, which require a specialized laboratory, highly trained personnel and controlled conditions, the use of the GeneXpert simplifies the entire process and allows testing directly at the patient’s site, such as an office or clinic.

In simpler terms: Without the GeneXpert machine, the detection process would take weeks or even months in national reference laboratories for tuberculosis.

In addition, this molecular diagnostic technology platform used to detect specific pathogens in biological samples is often applied in more diseases, such as HIV, hepatitis, respiratory infections, sexually transmitted diseases (STDs), among others.

Without the GeneXpert machine, the detection process would take weeks or even months in national TB reference laboratories.

GeneXpert alone is not enough

Of course, having the GeneXpert machine alone is not enough to access faster TB diagnostics. Actively searching for TB is one of the most effective actions in the fight against this disease, ensuring that people with symptoms receive the proper diagnosis and necessary treatment in time.

One of the initiatives developed by Socios En Salud is the TB Mobile, made up of two campers, known as the “blue trucks.” They are equipped with a digital radiography machine, a laptop with CAD4TB software, and materials for interventions. These vehicles travel through streets, squares, parks and markets, prioritizing areas with high TB burden and can attend more than 210 people per day.

If any abnormality is identified in the X-ray, a sputum sample is requested to perform the GeneXpert molecular test. This system has a sensitivity of over 80% and can detect rifampicin resistance, thus allowing the appropriate treatment scheme to be determined from the outset.

For its part, the Mochila TB is another innovative technological tool promoted by Socios En Salud that combines digital radiology, artificial intelligence and molecular biology. Unlike conventional X-ray machines, it emits less radiation and is easily transportable and can be assembled in different areas. It has the capacity to treat approximately 80 people per day.

Training of healthcare personnel is also crucial to maximize the effectiveness of these technologies. Community agents play a vital role by conducting home visits and organizing awareness campaigns, breaking the stigma associated with TB and encouraging early detection.

PIH advocates for cheaper GeneXpert

While GeneXpert tests have revolutionized the diagnosis of infectious diseases such as tuberculosis (TB), HIV and hepatitis C, their high cost prevents many people in low- and middle-income countries, such as Peru, from accessing them.

Thus Partners In Health, together with MSF Access Campaign, Treatment Action Group (TAG) and more than 150 civil organizations, have joined together in a campaign called “Time For $5” that seeks to change this reality. This global mobilization and advocacy effort demands that Cepheid and Danaher reduce the price of all GeneXpert tests to $5, allowing for broader access.

In September 2023, Danaher announced a 20% reduction in the price of the standard TB test. Although the cost decreased from $9.98 to $7.97, the reduction is still far from the $5 demanded.

In addition, Danaher committed to an annual third-party assessment of the cost of GeneXpert tests. This audit is crucial to ensure transparent and fair pricing, but details on its implementation have not yet been provided.

In advocacy for cheaper GeneXpert, PIH and its allies in this crusade released a technical report in September of this year highlighting the need for the audit to be conducted in a timely and rigorous manner. This is vital to expanding access to life-saving diagnostics around the world.

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