Hologic, Inc. announced preliminary revenue guidance for the first fiscal quarter ended December 30, 2017. The company expects to report total revenues of approximately $791 million, an increase of almost 8% compared to the prior year period, and a 7% increase in constant currency. These preliminary results compare to the company's prior guidance range of $775 to $790 million. The company expects its non-GAAP effective tax rate to be approximately 23% to 24% in fiscal 2018, lower than its prior guidance of approximately 31%. The company expects its GAAP effective tax rate to be negative for the year, largely based on the revaluation of its deferred taxes, but this analysis is ongoing.