Researchers have developed a blood test that can rapidly tell whether someone is suffering from tuberculosis. Investigators hope the test can lead to quicker treatment, making a dent in the worldwide TB epidemic.
One-third of the world's population is infected with a silent form of tuberculosis, according to the World Health Organization. A person can live for years infected with latent TB and show no symptoms.
But each year, 10 million people develop active TB, which causes severe symptoms — such as coughing, weight loss, fever and night sweats — and kills about 2 million of those people. Prompt diagnosis and treatment is critical for containing the highly contagious disease and saving lives.
The new blood test promises to provide that speedy diagnosis. Investigators say it can tell within hours whether someone is infected with mycobacterium, the pathogen that causes tuberculosis.
Currently, TB diagnosis is done with a sputum test. The objective is to grow the bacterium in culture from expelled mucus.
Arizona State University bioengineering professor Tony Hu, who helped develop the new test, said the sputum test takes too long.
"That technology needs four to eight weeks to get the final result," he said. But for the blood test, it's "only 2½ hours."
Called Nanodisk-MS, the rapid TB test takes advantage of nanotechnology to detect minute levels of peptides in the blood. Peptides are amino acid fragments of proteins that TB bacteria release only during active infections.
The highly sensitive blood test, described in the journal Proceedings of the National Academy of Sciences, can also measure the severity of the infection.
Nanomedicine such as this, Hu said, could also be used to monitor patients who are being treated with antibiotics to see how well they are responding or whether the antibiotic cocktail is the right one. He called it a form of personalized medicine that "can really save lives."
Hu said the test needed further validation in clinical trials, but that he hoped it would become part of the arsenal in the global war on tuberculosis.