Health care workers will be free to run experimental tests on blood and other samples taken from people who have fallen sick as a result of a bioterrorist attack, bird flu outbreak, detonation of a dirty bomb or any other life-threatening public health emergency, according to the rule issued by the Food and Drug Administration.

In all other cases, the use of an experimental test still requires the informed consent of a patient, as well as the review and approval of an outside panel.

"To be candid, I hope it is a hypothetical problem. I hope we spent a lot of time creating a rule we never have to invoke,'' said Dr. Steve Gutman, director of the FDA's in-vitro diagnostics office.

Determining what constitutes a life-threatening public health emergency would be left up to the laboratories doing the testing. That creates the potential for conflicts of interest and other abuses, critics said.

"I don't like a rule like this because its most likely use is likely to be a form of abuse. The emergency exception it creates will be stretched to encompass non-emergency situations,'' said Jim Harper, director of information policy studies at the Cato Institute.

The FDA said it published the rule to ensure the ability to identify quickly whatever chemical, biological, radiological or nuclear agent is involved in a terrorist attack or natural outbreak of disease. Doing so could save the lives of those being tested as well as of others exposed, the FDA said.

"Baloney,'' said Dr. Deborah Peel, chairwoman of the Patient Privacy Rights Foundation, a watchdog group. "This sounds like they're taking for themselves the right to test individuals every time they declare a public health emergency. There is no way getting consent would delay testing.''

The FDA said that obtaining informed consent in those cases would be impracticable or unfeasible.

The rule lays out a scenario where a laboratory discovers what appears to be an unusual bug in a sample taken from a patient before a public health emergency was even suspected. With the apparent bug in the lab but the patient gone, going back for permission to use a confirmatory but experimental test - often the only type of test available - would introduce "unacceptable delays,'' the FDA said.

"They're basically overriding state informed-consent laws,'' said Sue Blevins, president of the Institute for Health Freedom. Blevins said her group advocates for informed consent but that in emergencies it could be sought after the fact.

"If they don't have the time to get it, at least inform them retroactively what's been done, so people can keep track of what information has been collected from them,'' Blevins said.

The rule took effect Wednesday but remains subject to public comment until Aug. 7. The FDA said it published the rule without first seeking comments because it would hinder the response to an outbreak of bird flu or other public health emergency.

"Nobody said two airplanes would fly into the World Trade Center, did they? We wouldn't have written the rule unless we thought it was a possibility,'' Gutman said.

The FDA said the lack of such an exemption impeded the public health response to the Severe Acute Respiratory Syndrome, or SARS, epidemic of 2003.

On the Net:

Food and Drug Administration rule: http://www.fda.gov/OHRMS/DOCKETS/98fr/E6-8790.htm