UMass Memorial Medical Center in Worcester, which has been restructuring operations to improve its finances, said Tuesday it has signed an agreement to sell the hospital’s clinical outreach laboratory business to Quest Diagnostic for an undisclosed price.

The medical center, part of UMass Memorial Health Care — the largest health care system in Central Massachusetts — said the sale was the first step toward an alliance in which UMass Memorial could take a financial stake in a new venture that would operate a state-of-the-art lab in Massachusetts.