Bayer Diabetes Care, a division of Germany's Bayer AG ( BAY), has acquired Metrika, a privately-held company based in Sunnyvale, Calif., that makes a diabetes-monitoring system.

Financial details weren't disclosed. Metrika markets the A1CNow+, a meter-based system that has single-use, disposable test cartridges. A1CNow+ is a pager-sized device that people with diabetes can use to monitor HbA1c, the standard measure of blood-sugar control.

HbA1c is also known as glycated hemoglobin. The A1CNow+ provides access to HbA1c results in five minutes.

Bayer's American depositary shares fell 48 cents, or 1.1%, to $45.15 in U.S. trading Thursday.