Employers may need to dig deep into regional medical procedure pricing as they strive to hold down health plan costs.

A study of regional cost variances for female-specific procedures by Castlight Health found huge variances for such common procedures as mammograms, preventative primary gynecological exams, and OB/GYN follow up  visits.

In the case of mammograms, the ranges were highest in the major metropolitan area of New York ($130-$1,900), Dallas-Forth Worth ($50-$1,050), and Los Angeles ($86-$954).

Metro areas in Florida also reported wide price ranges, as did San Francisco, Philadelphia, and Detroit.

Even smaller markets reported surprising differences. The Visalia-Tulare-Porterville SMSA had a range of $77 to $307, and prices ranged from $97 to $214 in Dayton,  OH.

Read: Annual family health costs hit nearly $25K

But employers in 74 markets can take heart from the study: In those markets, there was essentially a single price for a mammogram.

Some of those markets were a bit on the high side—Janesville-Beloit, WI, for instance, reported a mammogram charge of $507,  Eau Claire, WI, $486, and Jackson,  MS,  $446.

But from a planning standpoint, knowing the cost is far better than learning that it can vary widely—after getting the bill.

The mammogram data was extracted and reported by Kaiser Health News.