A new test could dramatically improve the speed and accuracy of diagnosing tuberculosis (TB), allowing health care providers to report test results in minutes.
Findings from the first human clinical trial show the test can determine if a patient has tuberculosis with 86 percent sensitivity and 73 percent specificity.
The test 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 are combined with the reactive substance, a portable tabletop device, the TB REaD, is then used to detect any fluorescence and deliver the diagnosis in as little as 10 minutes.
“It’s simple. Take a sputum sample, treat it with the solution, and put it inside the reader,” says Jeffrey Cirillo, a professor at the Texas A&M University Health Science Center College of Medicine. “A camera inside looks for a reaction between the sample and solution that produces light. No light, no infection.”
Smear microscopy, the most widely used test in the world, has a significantly lower ability to detect TB, ranging between 50 to 60 percent 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.
EASY, INEXPENSIVE, AND QUICK
Currently, there is no diagnostic tool comparable to this 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 cost upwards of $20,000.
The target price tag on Cirillo’s test is less than $1,000 for the reader and less than $5 per test.
Additionally, 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.
POTENTIAL TO ERADICATE TB
The device significantly undercuts current diagnostic methods, which is important given the staggering statistic that if left untreated—a common scenario in many countries—a person with active TB has only a 50 percent chance of survival, Cirillo says.
“Interrupting disease transmission will require early and accurate detection paired with appropriate treatment,” Cirillo says. “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 test 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, Cirillo’s detection platform—Reporter Enzyme Fluorescence—could be applied to many other respiratory diseases and infectious agents.
Cirillo worked in collaboration with GBDbio, a Texas A&M spinoff, and researchers at Stanford University. The Wellcome Trust supports the project.
《Fluorogenic Probes with Substitutions at the 2 and 7 Positions of Cephalosporin are Highly BlaC-Specific for Rapid Mycobacterium tuberculosis Detection》, Published on Journal 《Angewandte Chemie International Edition》in July 2014.