Japanese medical equipment firm Terumo Corp said on Monday it plans to buy U.S. medical device company CaridianBCT from Sweden's Gambro AB for $2.6 billion, in a move that will make it the world's biggest equipment-maker for blood banks.

Colorado-based CaridianBCT specializes in making equipment used in blood banks and other disposable medical devices. It had total sales of $524 million in the year that ended in December.

Terumo, which currently ranks No.5 in the global blood banking business, said the acquisition would help it achieve 70 billion yen ($850 million) in annual sales in the sector.

Terumo said it plans to use cash available and bank loans to complete the deal, which it plans to close by May.

Terumo's shares closed down 1.75 percent at 4,495 yen before the announcement, while the Nikkei 225 average lost 1.8 percent.

(Reporting by Mariko Katsumura; Editing by Joseph Radford)