New tuberculosis blood test approach could boost early diagnosis

A new blood-based testing approach could help improve early diagnosis of tuberculosis.

Tuberculosis (TB) remains one of the world’s deadliest infections. Earlier diagnosis could reduce the risk of severe lung damage and limit the spread of the disease.

Dr Hannah Schiff is leading research into whether protein signals in the blood can reveal TB before patients become seriously ill.

Dr Schiff is a Senior Clinical Lecturer in Respiratory Medicine at the University of Southampton. She is part of the NIHR Southampton Biomedical Research Centre.

‘Particularly challenging’

“Mycobacterium tuberculosis is an ancient organism that we’ve never eradicated,” says Dr Schiff. “What makes it particularly challenging is that whether it causes disease depends as much on the person as it does on the bacterium.”

Often associated with low‑ and middle‑income countries, TB is now an increasing concern in the UK. England records more than 5,000 cases each year and is at risk of losing its low‑incidence status.

The disease spreads through microscopic droplets released when someone with active TB coughs. This is typically during prolonged contact. However, infection doesn’t always lead to illness.

An estimated one-third of the global population carries latent TB. This is a dormant form in which the bacteria lie ‘asleep’ in the body. It causes no symptoms and often remains undetected for decades.

“The immune system can contain the infection for a long time,” explains Dr Schiff. “But later in life – through ageing or immune suppression – it can reactivate and cause disease.”

When that happens, TB can cause extensive damage to the lungs, including scarring and cavitation. Even after successful treatment, many patients are left with permanently reduced lung function. 

Closing the diagnostic gap 

TB is curable, but timing is critical.

“Even in countries with strong health systems, it can take months from symptom onset to diagnosis,” says Dr Schiff. “During that time, the disease continues to spread and lung damage progresses.”

Currently, diagnosis relies largely on sputum (phlegm) samples. These are examined under a microscope, cultured or tested for bacterial DNA. These methods can be slow, poorly sensitive and costly, with lung damage progressing during the wait for results.

Closing this diagnostic gap is the central aim of Dr Schiff’s research.

“If we can diagnose TB earlier, especially in people who don’t yet know they’re sick, we can protect their health and the health of everyone around them.”

Detecting TB in blood 

Dr Schiff’s work explores whether TB leaves detectable traces in the blood long before severe symptoms develop. 

Her research focuses on protein biomarkers. These are molecular signals released into the bloodstream in those with the disease.

“My PhD looked at what happens in the blood during TB,” she says. “The cavitation caused by the disease is thought to release proteins into the blood, and we wanted to know if we could detect them.”

Using large patient datasets, her research has identified combinations of blood proteins. These can distinguish TB not only from healthy individuals, but also from other lung infections.

Dr Schiff is now working with collaborators in Southampton and Liverpool to validating these findings. She is using advanced protein array technology, which allows many biomarkers to be tested at once.

The ultimate goal is to develop rapid, point‑of‑care tests that could be used in clinics, hospitals and low‑resource settings worldwide.

“TB has never been eradicated,” says Dr Schiff, “but if we can detect it earlier and more accurately, we have a real chance to change how the disease is controlled.”