Blood Test Screens for Acute Tuberculosis in Asia

An innovative tuberculosis (TB) screening strategy detects antibodies in the blood that are only found when a person is fighting off active Mycobacterium tuberculosis infection.

In conventional screening, laboratory scientists must identify the bacterium in a sputum sample observed under a microscope, but rarely pick up more than 50% of active cases of pulmonary TB.

Scientists at the University of California, Davis (CA, USA) working with colleagues in Pakistan, used a combination of multiplex microbead immunoassays and computational tools for data analysis to study active TB patients. Multiplex analyses were performed on samples from apparently healthy individuals without active TB from the same community as the TB patients to establish the assay baselines for all analytes. Over 3,000 data points were collected from 135 patients and 37 controls.

Preliminary studies have shown that the antibody test can detect active TB in about four out of every five cases picked up by the sputum microscopy test. It can also detect four out of five active cases that the sputum test misses. Therefore, overall, it can identify about 80% of active cases compared with 50% for the sputum test. The initial cost of the antibody testing machines are higher than current assays, but the technology allows for so many more people to be tested, that the cost per patient would be about the same when used on a large scale.

The antibody test was designed to be compatible with an existing "high throughput" screening system so that it could be put to practical use quickly. The screening instrument, developed by Luminex Corporation (Austin, TX, USA) is already used in other clinical laboratory screening settings. The TB screening system can analyze about 100 TB patient samples in two hours.

Imran H. Khan, the senior author of the study, said, “The fast turnaround time of the new antibody diagnostic test, in combination with high number of patients who can be tested, should enable millions of more TB patients to be screened. As a result, effective treatment can be provided in a more timely fashion to reduce the spread of this deadly disease." The study was published in the August 2013 edition of the journal Clinical and Vaccine Immunology.

Related Links:
University of California Davis
Luminex Corporation