Johnson & Johnson said today that it’s been offered $4.15 billion by The Carlyle Group for its Ortho-Clinical Diagnostics business, a year after J&J began reviewing strategic options for the blood-testing unit as part of a routine pruning of its extensive family of businesses.

J&J, based in New Brunswick, New Jersey, has until March 31 to decide whether to accept the offer. Johnson & Johnson executives plan to discuss the offer Tuesday, when the health giant and consumer products company reports fourth-quarter results. The company said today that it will consult with works councils and trade unions representing the unit’s employees before making a decision.

The Ortho-Clinical business serves hospitals, testing laboratories and blood banks.

One division supplies equipment and chemicals to screen donated blood for HIV, hepatitis C and other serious diseases, and for typing donated blood to ensure patients get safe, compatible blood transfusions. The other division makes technology for advanced testing of blood to diagnose a range of health conditions and to monitor the effects of medication.

Established in 1937, Ortho Clinical Diagnostics is based in Raritan, New Jersey, and has factories in Rochester, New York; Pompano Beach, Florida, and Pencoed, Wales. It has more than 4,500 employees and operates in more than 30 countries worldwide.

Last January, CEO Alex Gorsky said J&J was looking at strategic options for Ortho-Clinical Diagnostics, which doesn’t meet the company’s long-held strategy of focusing on businesses that rank first or second in their markets.

In 2012, J&J reported just $530 million in revenue for its diagnostics division, down 4 per cent from 2011.

Carlyle Group is a private equity and buyout firm based in Washington, DC. If the sale goes through, Carlyle is expected to try to expand the business through increased marketing and creation of new products. Carlyle manages more than $185 billion worth of assets worldwide, according to its website.