New diagnostic TB test expected to provide more efficient results
(7 May 2009: VIDYYA MEDICAL NEWS SERVICE) -- Dr. David Alland, chief of the Division of Infectious Disease at UMDNJ-New Jersey Medical School, has developed a diagnostic test for tuberculosis called Xpert® MTB/RIF that will enable clinicians to provide patient results quickly and efficiently. The test is currently available in Europe. Dr. Alland was the primary investigator of a grant from the National Institutes of Health that supported the research.
European clinicians will now have access to a rapid detection test that can simultaneously identify Mycobacterium tuberculosis (MTB) and resistance to rifampicin (RIF), a common first-line drug for treatment of the disease and a reliable surrogate marker of strains that are multidrug-resistant (MDR-TB). The test is currently available in Europe only. There are plans to unveil the test in the United States pending approvals by the U.S. Food and Drug Administration (FDA).
Dr. Alland, also assistant dean for clinical research at UMDNJ-New Jersey Medical School, believes the Xpert® device will transform TB diagnostics. “It brings the diagnostic laboratory to the patient’s bedside and provides results within hours,” said Dr. Alland. “We are very excited and hopeful that this test will dramatically improve tuberculosis detection and treatment.”
Health officials from Cepheid, the manufacturer of the device, believe the test will fill the need for accurate and rapid detection of tuberculosis, which is becoming increasingly acute. Currently, the most common testing method for TB is sputum microscopy, or the smear test, that has remained largely unchanged in its sophistication and sensitivity for more than 100 years. The smear test has been proven to detect only about half of all active TB cases and is not capable of identifying drug resistance. As a result, TB is under-diagnosed.
Patients who remain undetected are often co-mingled within general hospital populations, placing others at risk of infection. Due to their low accuracy, smear tests are followed up with culture tests, which offer more accurate results but take several weeks. To determine drug resistance, culture testing can take months to return a result.
Sputum microscopy, which often delivers poor sensitivity in patients suffering from tuberculosis, is almost completely ineffective in those who also have HIV co-infection. The weakened immune system of an HIV-positive person is particularly susceptible to infection, resulting in one-third of the 33 million HIV sufferers worldwide becoming infected with TB. Left untreated, 90 percent of these people will die within months of first contracting the disease, reinforcing the urgent need for an accurate and rapid test.
“We designed this test so that it could be used by someone with minimal training,” said Dr. Alland. “We're gratified to find that it requires less hands-on work than the acid fast smear, long a standard method to identify tuberculosis, but it is much more sensitive.”
Dr. Alland worked with Cepheid and the Foundation for Innovative New Diagnostics (FIND), with support from the National Institute of Allergy and Infectious Diseases (NIAID) in developing the test.
According to the World Health Organization (WHO), approximately two billion people are currently infected with MTB. An estimated nine million people develop active TB each year, and two million people lose their lives to the illness. This equates to one life every 20 seconds.
UMDNJ-New Jersey Medical School is the home of The Global Tuberculosis Institute. The institute plays a leading role in the international arena, providing expertise in program development, education, training and research. In 2005, the CDC charged the Institute with strengthening the public health response to TB in the northeastern U.S. With support from CDC, the Institute established the Northeastern Regional Training and Medical Consultation Center, which covers 16 states from Indiana to Maine and the cities of Philadelphia, Baltimore, New York and Detroit.
The University of Medicine and Dentistry of New Jersey (UMDNJ) is the nation's largest free-standing public health sciences university with more than 5,500 students attending the state's three medical schools, its only dental school, a graduate school of biomedical sciences, a school of health related professions, a school of nursing and its only school of public health, on five campuses. Annually, there are more than two million patient visits at UMDNJ facilities and faculty practices at campuses in Newark, New Brunswick/Piscataway, Scotch Plains, Camden and Stratford. UMDNJ operates University Hospital, a Level I Trauma Center in Newark, and University Behavioral HealthCare, a mental health and addiction services network.
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