The Food and Drug Administration said Wednesday that Abbott Laboratories is recalling up to 359 million testing strips used by diabetics because they can give falsely low blood sugar readings.

The testing strips are used to help diabetes patients check their blood sugar levels. But the FDA says the products being recalled by Abbott can give inaccurately low measurements. As a result, patients may try to raise their blood sugar levels unnecessarily or fail to detect dangerously high blood sugar levels.

The FDA said the problems are caused by a defect that limits the amount of blood absorbed by each strip.

North Chicago-based Abbott is recalling 359 lots marketed under a half-dozen brand names, including: Precision Xceed Pro, Precision Xtra, Medisense Optium, Optium, OptiumEZ and ReliOn Ultima.

Abbott said ReliOn Ultima test strips are used with the ReliOn Ultima blood glucose monitoring system and that system is not being recalled.

Abbott said it will replace the affected test strips at no charge.

Shares of Abbott fell 10 cents to $47.90 in afternoon trading.