Fast, cheap and convenient environmental toxic tests developed byUC Davis researchers just became more accurate and less expensive, thanks to David M. Rocke, a statistician in the UC Davis Graduate School of Management. Rocke and his colleagues gave the test protocols a mathematical boost with a model that figures out how to minimize analytical errors. The biologically based tests, based on the Enzyme-Linked Immunosorbent Assay (ELISA), detect chemicals using antibodies sensitive to certain compounds (working on the same principle as an at-home pregnancy test). Even without the new mathematical model, ELISA environmental tests are much cheaper than previous methods. For example, Rocke estimates, if a government agency had a $10,000 budget to monitor toxics in the Sacramento River, it might buy 100 gas chromatography tests or 10,000 ELISAs of equivalent precision. (UC Davis professor Bruce D. Hammock, head of the campus's multimillion-dollar Superfund research program, has been a leading researcher in adapting the popular medical technique for use in measuring environmental toxins, such as pesticides in rivers.) However, Superfund researchers at UC Davis saw even greater potential for the ELISA method. On each ELISA test plate, up to one-third of the space is given to control samples, leaving less room for environmental samples. Rocke's model eliminates the need for some of the control samples, thus squeezing more environmental samples on each plate for the same cost without sacrificing accuracy. The model extends beyond the environmental use to such ELISA settings as AIDS testing, Rocke says, and beyond the ELISA test to other methods. Rocke will talk about his work Wednesday, April 8, 9:20 a.m. at the Moscone Center L.