New TB Test Offers Quicker Diagnosis
Simple device could cost less than $1,000
A new test for tuberculosis (TB) could dramatically improve the speed and accuracy of diagnosis for one of the world’s deadliest diseases, enabling health care providers to report results to patients within minutes, according to a study published in Angewandte Chemie.
Jeffrey Cirillo, PhD, a professor at the Texas A&M Health Science Center College of Medicine, in collaboration with investigators at Stanford University, has developed a new chemical compound that identifies the bacteria that cause TB with a level of sensitivity that currently takes months to produce.
Results from the first human clinical trial have shown that the test can determine whether a patient has TB with 86% sensitivity and 73% specificity. Smear microscopy, the most widely used test in the world, has a significantly lower ability to detect TB, ranging between 50% and 60% sensitivity.
Although preventable, TB claims three lives every minute, making it the second leading cause of mortality from an infectious disease in the world. Spread through the air when an individual with active TB infection coughs or sneezes, reports show that if left untreated, a person with active TB infects an average of 10 to 15 people each year, leaving a great need for faster, more reliable testing.
Using a fluorescent substrate, the new device targets BlaC (an enzyme produced by the bacteria that cause TB) as an indicator of the bacteria’s presence. Until now, it has not been possible to target a specific TB enzyme for diagnosis.
Once sputum samples have been combined with the reactive substance, a battery-powered, portable tabletop device, the TB REaD, is used to detect fluorescence and to deliver the diagnosis in as little as 10 minutes.
“It’s simple,” Cirillo said. “Take a sputum sample; treat it with the solution; and put it inside the reader. A camera inside looks for a reaction between the sample and solution that produces light. No light, no infection.”
Currently, no diagnostic tool is comparable to the new device, and while others exist, they take several months to produce the same level of sensitivity and come with a high price tag. The latest FDA-approved model costs more than $20,000. In contrast, the target price tag on Cirillo’s test is less than $1,000 for the reader and less than $5 per test.
In addition, the one-step test will require little technical expertise or resources; should take less than 30 minutes to carry out; and is easily transportable, making it an ideal candidate for field diagnosis in developing countries, according to Cirillo.
“Interrupting disease transmission will require early and accurate detection paired with appropriate treatment,” he said. “Our new, rapid point-of-care TB test dramatically reduces the current delays in diagnosis with incredible accuracy, accelerating appropriate treatment and reducing the death rate of the highly infectious disease. We’re looking at a low-cost, easy-to-use test that has the potential to eradicate TB.”
The TB REaD device is currently in the later stages of clinical trials, with plans to go to market in the next 18 months. Although the first applications will be in TB, the device could be applied to many other respiratory diseases and infectious agents, Cirillo says.
Source: Texas A&M Health Science Center; July 3, 2014.