WRAL

NC Health Official Says Low Accuracy Rate Of Anthrax Field Tests Is Troubling

The deputy Director of North Carolina's Public Health lab, John Sheats, says the accuracy rate for the field tests Haz-Mat teams across the state are using is troubling.

"They lack precision and they lack accuracy," he says. "That's why we recommend that you do lab work."

Sheats says that some of the better tests have a 30 percent false positive rate and that some of the ones that are not quite as good have a 50-50 positivity rates.

He says about the only time a field test is really reliable is when the spore count of the substance tested is very high -- 10,000 spores or more -- and that is rare.

"Ten thousand spores could fit on the head of a pen," he says. "There are anthrax spores in the environment, but widely dispersed, so it would be uncommon to come in contact with 10,000 spores."

Some authorities have been using field tests results to decide whether to evacuate a building or quarantine a person. But Sheats says that is as far as serious decisions should go.

"You really shouldn't use it to administer patient prophylactic or manage care of a patient," he says.

The Department of Health and Human Services says the state has received about 250 substances for testing over the past couple of weeks. Approximately a dozen of those had tested positive for some type of biological bacteria in the field. More thorough testing proved none of cases involved anthrax.

-- Anonymous, November 04, 2001