Beth Israel Hospital (BIH) received a $2.5-million grant this month to help finance expansion of a Harvard medical laboratory, Dr. Mitchell T. Rabkin '51, general director of BIH, said yesterday.

The Charles A. Dana Foundation of Greenwich, Conn., awarded the grant to aid construction of a four-story addition to the Harvard-Thorndike Research Laboratory, the oldest clinical research laboratory in the country.

The expansion will cost about $12 million, and will not increase patient care costs, Rabkin said. He added that the new facility will benefit all departments active in laboratory research.

"I think it's quite a coup," Dr. Harold A. Dvorak, Mallinckrodt Professor of Pathology, said yesterday in reference to the $2.5 million grant. The 2500 square feet of research space his department will gain means probably two or three additional staff investigators at the assistant professor level, he added.

Two Long Years

Construction of the research facility, to be named after Dana, will begin this fall and last about two years, Rabkin said. BIH, a Harvard teaching hospital, promised to expand the Thorndike Lab in 1972, when the lab moved to BIH, he added.

The "very active research program" necessitated the expansion, Dr. William Silen, Johnson Professor of Surgery, said yesterday. "We've been constrained only by the lack of space and the heavy teaching load," he said, adding that he will hire at least three additional instructors in surgery.

Rabkin noted that hiring additional professionals depends on acquiring larger research grants. "By expanding, we're betting on the quality of the academic work of our staff," he added.

The Dana Building will be a four-story beige brick addition over the present four-story building, Martha L. Rothman, co-architect, said yesterday. Plans include minimal renovation of the existing building and addition of 87,000 gross square feet of space, she added.