A federal judge has granted class action status to a lawsuit accusing Abbott Laboratories Inc. of cheating older workers out of retirement benefits when it spun off its hospital equipment business in 2004.

Last week’s ruling by U.S. District Judge Robert W. Gettleman allows the suit to cover all Abbott employees shifted to newly created Hospira Inc. between Aug. 22, 2003 — the date the spinoff was announced — and April 30, 2004. Also included are Hospira employees who were eligible to retire from Abbott when their jobs were eliminated.