Abbott's fourth-quarter results, 2018 profit forecast beat estimates

(Reuters) - Abbott Laboratories' fourth-quarter results and 2018 adjusted earnings forecast beat Wall Street estimates as the healthcare company gains from its recent purchase of rivals such as St.Jude Medical and Alere.

The company's shares rose 2.6 percent to $60.75 before the bell on Wednesday.

Sales from Abbott's medical device business - its largest division - grew 9.6 percent on an operational basis to $2.74 billion in the quarter ending Dec. 31.

The unit includes devices Abbott picked up from its $25 billion acquisition of St. Jude Medical that was completed last year.

Sales for its diagnostics unit jumped 6.7 percent and raked in $1.91 billion, bolstered by the completion of its $5.3 billion Alere buy in the quarter.

Sales in Abbott's nutrition unit, which had been under pressure due to challenges in China, rose marginally.

"Abbott did not disappoint and the fourth-quarter print was impressive across the board," Evercore ISI analyst Vijay Kumar said in a client note.

The Chicago, Illinois-based company, however, posted a net loss of $828 million, or 48 cents per share, mainly related to a $1.46 billion charge due to the recent U.S. tax overhaul.

Excluding items, Abbott reported a profit of 74 cents per share, a cent higher than the average analyst estimate, according to Thomson Reuters I/B/E/S.

Net sales rose 42.3 percent to $7.59 billion, beating revenue expectations of $7.39 billion.

The company forecast full-year adjusted profit of $2.80 to $2.90 per share. Analysts were expecting a profit of $2.49 per share.

(Reporting by Divya Grover in Bengaluru; Editing by Supriya Kurane and Arun Koyyur)