Moody's Investors Service said Tuesday it put the debt of medical equipment maker Beckman Coulter Inc. on review for a possible upgrade after news that the company will be purchased by rival equipment maker Danaher Corp.

The ratings agency also put a "Baa3" rating on Beckman Coulter's $1.4 billion in debt. The outlook for Beckman's debt had been negative prior the outlook review.

The purchase by Danaher has been approved by both companies' boards of directors and is expected to close during the first half of the year subject to customary shareholder and regulatory approvals.

Danaher said Monday it would buy Beckman Coulter for about $5.87 billion, making Beckman part of Danaher's life sciences and diagnostics business.

Moody's said its review of Beckman's debt will focus mainly on the execution of the buyout, final terms of the deal and the treatment of Beckman's debt in Danaher's capital structure, including any guarantees or support mechanisms.

Danaher is currently rated A2 and is under review for possible downgrade, according to Moody's.

Shares of Beckman rose 8 cents to $82.74 during afternoon trading.