In 1983, an estimated 17 million to 22 million animals were used nationally in medical, scientific and educational laboratories for research and testing.

And while the use of lab animals is unlikely to be phased out entirely in the near future, more humane treatment of test animals is possible as is reducing the number used, said a recently released report by the congessional Office of Technology Assessment.

The study pointed out that internationally, researchers are increasingly being required to demonstrate that no less painful alternatives exist before they get the go-ahead to use animals.

Researchers can reduce the pain and distress of animals by administering painkillers and tranquilizers more liberally, the report suggested. In some cases, animal use can be reduced by substituting analysis of epidemiological data or using chemical systems that mimic biological functions.

In many life sciences and medical school classes, computers that simulate biology are already replacing traditional dissections. Chicken embryos or in vitro tests could be used as a substitute for rabbit eyes in many toxicity tests, the report said.

Rats and mice by far account for the majority of animals used in tests -- probably more than 15 million annually -- although the study said current reporting requirements make hard data impossible to collect.