WESTBROOK – Idexx Laboratories Inc., which makes diagnostic products for veterinarians and tests for livestock and poultry, posted a 15 percent increase in third-quarter earnings and raised its outlook for its full-year profits.

For the quarter, Idexx said earnings totaled $42.8 million, or 76 cents a share, compared with $38.5 million, or 66 cents a share, a year ago. Revenues rose to $315.5 million from $301.0 million a year ago.

In its companion animal group, or pets groups, revenues rose to $262.4 million from $248.1 million a year ago. It attributed the growth to gains in its reference laboratory diagnostic and consulting services business and its instrument and consumables business. It also benefitted from the acquisition of new customers due to geographic expansion.

Revenues in its water business rose to $22.2 million from $21.6 million. Revenues in its livestock and poultry diagnostics unit fell to $18.9 million from $20.7 million due to lower sales volume of certain bovine tests amid lower testing levels from some government programs in Europe.

For the full-year 2012, Idexx expects revenues to be about $1.30 billion, compared with previous guidance of $1.30 billion to $1.31 billion. Earnings per share are expected to be in the range of $3.08 to $3.11, an increase from its previous guidance of $3.05 to $3.10. It cited favorable changes in foreign currency exchange rates.

For 2013, Idexx expects revenues to be in the range of $1.405 billion to $1.425 billion. Earnings are expected to be in the range of $3.37 a share to $3.47 a share.

Shares of Idexx lost $1.37, or 1.38 percent, to $97.59 in morning trading on Nasdaq.