Scientists continue to pursue better methods of detecting anthrax.

An initiative conducted by AOAC International and funded by the departments of Defense and Homeland Security has approved two biodefense methods for the detection of Bacillus anthracis, or anthrax.

AOAC researchers are set to begin field-testing the first, a rapid screening hand-held assay intended to be used by first responders for the presumptive detection of anthrax.

In static tests, the RAMP Anthrax Test Cartridge was found to be reliable in detecting anthrax spores at levels of one million or more in visible powders.

In tests conducted at the U.S. Army Dugway Proving Grounds in Utah, the RAMP was demonstrated to reliably detect B. anthracis isolates representing a wide variety of geographic sources and physical variants. The specificity also was demonstrated in evaluations to confirm that the device would not cross-react with non-anthrax bacteria.

To judge the accuracy of the data, AOAC enlisted 12 laboratories nationwide to assess the RAMP's performance using identical samples. Little variation was seen in the data produced by the laboratories, according to AOAC.

The field-testing studies, still in the planning stage, will determine if field use affects the analytical performance of the assay.

The second method, a laboratory-only scheme called the MIDI Sherlock Microbial Identification System was subjected to a number of tests to assess its ability to distinguish between B. anthracis and several related strains. Eleven laboratories reported an overall acceptable sensitivity for B. anthracis identification of 96.3%.