By Tim Butters
Published Wednesday, December 31, 2008
| From the January 2009 Issue of FireRescue
Even before the events of Sept. 11 2001 the possibility of a chemical biological radiological nuclear or explosive (CBRNE) incident has been a concern of federal state and local public safety agencies and private industry. The response to known CBRNE agents is complicated enough for first responders. However responding to an unknown substance suspected of being a biothreat agent creates an entirely new set of challenges.
The early use of commercially available detection devices to conduct field analysis of unknown “white powder” substances proved problematic: In a number of instances these detection devices indicated that an unknown material contained B. anthracis (anthrax) spores or other biological agents which was later disproven after the sample was sent to a Laboratory Response Network (LRN) for analysis. As a result of the inaccurate information command officers unnecessarily quarantined isolated and decontaminated people.
Note: The problems associated with field detection are not only related to the analytical capabilities of the devices themselves but are also due to improper or nonexistent testing protocols and procedures or inadequately trained personnel.
Identifying the Need
The overall need to rapidly and reliably identify unknown substances in the field has been a topic of intense discussion by a wide range of stakeholders including emergency responders federal government agencies public health industry and academia.
Most stakeholders believe that currently available field test kits for identification of anthrax and biological agents aren’t sufficiently accurate. An FBI/Centers for Disease Control evaluation of five kits in 2003 confirmed these beliefs.1 However in more extensive testing by the Association of Analytical Communities (AOAC) for DHS in 2004 one kit did pass accuracy tests and was certified 2 demonstrating that accurate field testing is possible. In addition many first responders consider such kits a valuable and necessary asset because the public expects fire departments to be able to identify powders and such testing often helps maintain calm.
Handheld assays (HHAs) for the detection of unknown substances were originally made available to first responders in 1991 after the Gulf War. These “embedded flow” devices had problems and provided questionable results. The next generation of HHAs use “lateral flow” technology similar to over-the-counter pregnancy test strips. They often result in high number of “false positives ” as well as yield false negatives on positive samples.
Considering that the response to and treatment of human exposures to biological substances are typically not as acute as that of a chemical exposure as well as the costs associated with response and heightened public anxiety the benefits of using HHAs for unknown substance identification are limited until their accuracy is improved.
Additionally bio-detection systems are increasingly being installed in mail-handling facilities mass-transit facilities critical infrastructures entertainment venues and other complexes. But such systems are often unsupported by clear policies for on-site response actions by building occupants and emergency responders when these devices detect a potential agent. Local emergency responders may not be aware such systems have been installed. Working out response issues prior to bringing detection systems online is critical. Note: The Postal Service the Department of State and the Department of Defense have worked closely with responders in those areas where detection systems are installed.
Currently there’s no recognized system to identify reliable biothreat detection systems nor do any federal agencies certify or approve these devices.
The lack of a national standard has prompted a project led by the U.S. Department of Homeland Security (DHS) for the evaluation and validation of threat-agent detection systems. DHS selected the AOAC and Midwest Research Institute to establish a scientifically based set of standards processes that will be made publicly available. These standards would used for HHAs as well as substance identification that regularly takes place in a laboratory using polymerase chain reaction.
The first phase of the project involved bringing together a group of stakeholders representing government industry emergency responders public health and academia. This group referred to as the Stakeholder Panel on Agent Detection Assays (SPADA) is tasked with defining the performance criteria test methods for validation and types of materials required for testing that a given device would need to meet. AOAC is responsible for ensuring the criteria and methods developed by SPADA are in compliance with AOAC standards which are the recognized industry standards for analytical methodology.
In September DHS held a town hall meeting in Rockville Md. inviting emergency responders and others not only to discuss what SPADA had accomplished thus far but also to help provide DHS and the federal government with strategic direction for the project. Senior policy officials from DHS the FBI the Transportation Security Administration the Food and Drug Administration the Environmental Protection Agency and the White House Office of Science and Technology Policy also participated.
The meeting resulted in approval of the following five “articles” or recommendations intended to provide DHS and the new administration with strategic direction to achieve the development of a comprehensive threat-agent detection program:
1. Develop performance standards for CBRNE detection devices and technologies used by emergency responders and others.
2. Establish a program (in collaboration with other agencies standards-making organizations and industry) to qualify detection technologies and devices by an independent third party and make this program available as a recommended practice. Once this program is in place all detection devices must be qualified prior to their purchase by grantees and federally regulated venues.
3. Develop guidelines for training proficiency testing and certification of operators of qualified detection technologies.
4. Develop recommended standard operating procedures for bio-detection systems which should include the appropriate use and operation of qualified detection technologies as well as interpretation and response by the end user.
5. Develop strategic guidance on standards for CBRNE detector technologies for use by relevant critical infrastructure sectors key resources and others.
These recommendations will be part of a white paper that will include specific proposals of how to implement the approved articles and a recommended strategy for the future direction of the program that meets the needs of emergency responders law enforcement public health officials government stakeholders and private sector developers of detection technology.
What the Future Holds
As new bio-detection devices and systems are developed and introduced for field detection and agent identification the need for an accurate robust methodology for assessing their reliability is critical. Although the near-term goal of this effort is to develop a mechanism to address the current issues associated with threats and detection systems the program must be able to accommodate evolving threat agents and necessary technologies required to address those new threats as well.
1 “Preliminary Findings on the Evaluation of Hand-Held Immunoassays for Bacillus anthracis and Yersinia pestis.” Downloaded from: http://www.fbi.gov/hq/lab/fsc/backissu/jan2003/fsru.htm
2 B. Harper & M. Robinson. “Method Modification (2004.08) to Field Testing of Visible Powders on a Variety of Nonporous Environmental Surfaces: Field Study.” Journal of AOAC International Vol. 89 No. 6 2006.
What Is PCR?
PCR stands for polymerase chain reaction a technique widely used in molecular biology microbiology genetics diagnostics clinical laboratories forensic science environmental science and many other applications. It’s a laboratory procedure that employs a number of steps to isolate amplify and replicate DNA from an unknown substance. Because DNA has a unique structure or signature the unknown substance can then be identified based on the DNA.
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