Gull Laboratories, a Salt Lake-based manufacture of medical diagnostic test kits marketed worldwide, has started listing its stock on the national over-the-counter market.

Shares will be on the NASDAQ listing under the symbol "GULL.""Gull sought listing on NASDAQ to better provide market makers, brokers and others ready access to pertinent stock information," said Gull president and founder Myron Wentz.

The company reported six month sales of more than $2.1 million, a 31 percent increase over the first half of last year, and anticipates $4.4 million total sales in 1988.