The U.S. Food and Drug Administration is notifying health care providers and patients of a problem with blood glucose meters made by Abbott Diabetes Care, Alameda, California.

The meters can unintentionally be switched from one unit of measurement to another, resulting in an inaccurate blood glucose interpretation by the user. Users in the United States should make sure that their meter reading is displayed as mg/dL because an inaccurate reading can lead to taking the wrong dose of insulin or dietary changes, resulting in higher levels of sugar in the blood or hyperglycemia. Hyperglycemia can be a serious and even life-threatening condition and several cases of hyperglycemia have been reported to FDA.

The meters are designed to report blood glucose levels in two different measurements which are the US standard - milligrams per deciliter or mg/dL, and the foreign standard, millimoles per liter or mmol/L-and can be accidentally switched from one measurement to the other. The switch may occur when a user is setting the time and date for the meter. There also have been reports of the measurement being switched after a meter was dropped or after replacement of the battery. Abbott has not confirmed these additional causes of failure.

A FDA release states that Abbott is not instructing users to return their blood glucose meters. The firm issued a press release on October 14, 2005, and has undertaken a worldwide correction and notification to all healthcare professionals and users, when known, about the measurement switching problem. All Abbott glucose meters currently being shipped for distribution are locked with the correct unit of measurement.

The affected glucose meters made by Abbott that are sold in the United States include FreeStyle, FreeStyle Flash, FreeStyle Tracker, Precision Xtra, MediSense, Sof-Tact, Precision Sof-Tact, MediSense, Optium, and private label brands ReliOn Ultima, Rite Aid, and Kroger blood glucose meters. Precision Sof-Tact meters, which were inadvertently omitted from Abbott’s press release, also are subject to this action. These products are distributed primarily through retail and mail order pharmacies and physicians' offices.

Affected glucose meters sold outside of the United States are Xceed, Liberty, Boots, Xtra Classic, Easy, and SofTrac.