Roger W. Truesdail started Truesdail Laboratories, Inc. in 1931. At the time he was a professor of chemistry at the Pomona College in Claremont. Initially his laboratory analyzed only yeast products, however within a few months Dr. Truesdail foresaw a need for an independent laboratory capable of performing a wide spectrum of tests. Consequently, he added other laboratories and moved them to downtown Los Angeles where they remained for 52 years.