* Q1 oper profit 953 mln euros vs Rtrs poll avg 921 mln
* Operating margin widens to 23.9 pct from 23.4 pct
* Confirms 2013, 2016 outlook
* Shares indicated 2.7 percent higher
FRANKFURT, May 6 (Reuters) - Germany's Linde, the world's No. 2 industrial gases producer, reported a better-than-expected 12.6 percent gain in quarterly operating profit, boosted by last year's acquisition of U.S.-based Lincare.
Operating profit for first quarter through March was 953 million euros ($1.25 billion), Linde said on Monday, exceeding an average analyst estimate of 921 million euros in a Reuters poll.
Lincare, a provider of oxygen and respiratory therapy services to patients in the home, contributed 397 million euros of Linde's first-quarter sales of 3.99 billion euros.
Shares of Linde were indicated to open 2.7 percent higher, making them the biggest gainer on Germany's blue-chip DAX index .
The bulk of Linde's customers are in the steel-making, oil refining and semiconductors industries but its gases are also used to help asthma patients breathe more easily and lift the balloons in the Macy's Thanksgiving Day Parade in New York City.
Linde's main gases business grew compared with its smaller and less profitable engineering business, helping to lift the group operating profit margin to 23.9 percent from 23.4 percent.
Linde said it was still aiming for an increase in sales this year and operating profit of at least 4 billion euros thanks to the expected earnings contribution from Lincare.
It echoed recent upbeat comments by rivals, such as France's Air Liquide and U.S.-based Praxair Inc, which are banking on robust demand for industrial gases over the coming months.
Analysts on average see Linde's 2013 operating profit at 3.99 billion and revenue rising to 17.05 billion euros from 15.83 billion in sales last year. Linde also said it still sees operating profit rising to at least 5 billion euros in 2016.