Field Testing or LRN Laboratories - Why Not Both?

A true dilemma occurs when a choice must be made between two approximately equal and perhaps unappealing alternatives. The phrase “being between a rock and hard place” is a well known example of having two choices, neither of them very desirable.

Presumptive screening in the field vs. more definitive testing in a laboratory represents the “rock” and the “hard place” in many discussions about the identification of biological agents. Proponents of field-level detectors of biological agents – for example, District Chief Armando Bevelacqua of the City of Orlando Fire Department – are firm believers in the value of field screening. “There is an expectation that public-safety [agencies], especially the fire department,” Bevelacqua points out, “… [are] capable of handling suspicious powder calls.  We are looked at by the general public as all-around problem solvers.”

That public expectation, it seems obvious, includes a belief that the problem solvers mentioned possess both: (a) the training and expertise needed to determine if a threat is credible; and (b) the ability to use reliable field-detection instrumentation to make tactical-level decisions – very quickly. The tactical-level decisions just mentioned encompass such matters as returning a facility to normal operations after a hoax, offering peace of mind to persons who believe they have been “exposed” to a suspicious powder, and/or returning students to their rooms after a white-powder scare.

Reliable field testing,” Bevelacqua emphasizes, “gives you the ability to make informed decisions about the credibility of a potential situation or substance.” But it is the need for reliable results that most concerns those who believe that field testing produces questionable results.

A Major Decline in False Positives

In any discussion about the reliability of field tests, the first questions usually raised are about the possibility of false positive results. False positives occur when a device signals that a particular agent is present when it is not, thereby creating a situation that shakes the confidence of the on-scene user and leads to numerous problems for emergency managers and other officials who must make decisions based on the results of field tests. Here it should be noted that, as recently as seven or eight years ago, field tests were in fact highly prone to false positive readings. Since then, however, the rate of false positives has dropped dramatically, in large part because of the maturing of the overall market. As a result, in the last few years the entire field-testing marketplace has improved significantly in terms of reliable performance.

It is still true, of course, that some manufacturers continue to make unsubstantiated claims about the performance levels of their products, but not all technologies are suspect. There are, in fact, some very reliable and validated instruments available to the first-responder market. When those instruments are used by trained responders, the results obtained in the field will also be reliable.

Among the most rapid and reliable field-testing devices are those that use PCR (polymerase chain reaction) technology to make their assessments. Those assessments are extremely specific because the PCR technology identifies the DNA of the test sample – an obvious benefit to first responders.  Once limited to use only in the laboratory, more user-friendly PCR devices are now making their way into the first-responder market. [Sponsored Link]

These devices are similar in concept to laboratory testing methods – with the added advantages that they are portable, capable of withstanding the rigors of field use, and relatively easy to operate.   

Experts in the hazardous materials response field agree that the laboratory testing of biological agents is still the “gold standard” in the detection field, but the highly respected Laboratory Response Network (LRN – established in 1999 by the U.S. Centers for Disease Control and Prevention (CDC) – is not a 24/7 operation. Even in most major metropolitan areas, the LRN – which links federal, state, and local labs together in a truly national network – is not as quickly available as most local fire and police departments, and there are times when that unavailability becomes unacceptable.

The Gold Standard vs. Intangible Skills

One can easily imagine a situation in which a suspicious powder is found inside a busy shopping mall, in a large city, at the height of the Christmas shopping season. The entire mall might have to be evacuated, and thousands of dollars an hour in probable sales would be lost during the period when the mall is closed. Without a trained and properly equipped first-responder corps that can be on the scene on very short notice, the facility is at the mercy of the LRN, and could be closed for several hours, or even days, because there would be no reliable way to make a relatively quick decision about the nature of the suspicious substance.  

In that scenario, one of the major benefits provided by field screening would be that immediate information would be available about the substance in question. That information may not be quite as ironclad as the information obtained from culturing the sample in a lab, and/or using other high-end testing methodologies, but there is growing empirical evidence suggesting that, when trained responders use highly reliable instruments to make informed decisions, the usual result is a high percentage of accuracy. Keeping in mind the fact that there is a significant difference between analyzing a substance and analyzing a threat, it seems that the principal difference, therefore, between relying on the LRN and relying on the first-responder community is the intangible skill of assessing the incident (threat) as a whole, not just the substance itself.

Local responders are in that respect somewhat like “a triage center for the laboratories,” Bevelacqua says. “If the threat looks … credible, and the sample tests positive in the field – or we’re not sure about the results – the labs are going to get the sample anyway. That’s the way the process works.   All we do is weed out the [potential threats] … that are clear-cut hoaxes.”  

Viewed in that context, it seems that there is perhaps no real dilemma when deciding about the merits of testing a substance in the field instead of in an LRN laboratory – each method of testing serves a separate and distinct purpose. In other words, rather than seeing field testing for biological agents as a competitor to the LRN, or vice versa, the logical, and more practical, view should be of a cooperative situation, with each alternative having its own appeal as well as its own place in the overall identification process.

Rob Schnepp

Rob Schnepp is division chief of special operations (ret.) for Alameda County (CA) Fire Department. His incident response career spans 30 years as a special operations fire chief, incident commander, consultant, and published author. He commanded numerous large-scale emergencies for the Alameda County (CA) Fire Department, protecting 500 square miles and two national laboratories in the East Bay of the San Francisco Bay Area. He twice planned and directed Red Command at Urban Shield, the largest Homeland Security exercise in the United States. He served on the curriculum development team and instructed Special Operations Program Management at the U.S. Fire Administration’s National Fire Academy. He is the author of “Hazardous Materials: Awareness and Operations.” He has developed risk assessment, incident management, and incident command training for Fortune 500 companies, foreign governments, and U.S. national laboratories.



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