WASHINGTON — Many of the plastic identity bracelets that hospital patients wear will soon have an added bit of information embossed on them — a bar code containing information designed to make sure patients don’t get the wrong drug or dosage by mistake.

Federal officials said Wednesday that the additional information, which makes it possible to match individuals to their prescribed medications by computerized scanners, has the potential to cut in half the 7,000 hospital deaths attributed to medical error every year.

The move to computerized error prevention systems in hospitals received a major boost when Health and Human Services Secretary Tommy Thompson unveiled a regulation that requires drug makers and suppliers of blood to add the codes to most of their products within two years.

"The pharmaceutical industry wants it, hospitals want it, doctors want it — all we needed was the catalyst to put all it together," Thompson said Wednesday. "By giving providers a way to check drugs and dosages quickly, we create the opportunity to reduce the risk of medication errors significantly."

Despite their interest, hospitals have been reluctant to spend the money needed to set up computerized facility-wide scanning systems because few drugs now come in individual blister packs with the bar coding. The new rule is designed to jump start the nationwide adoption of bar-coding in hospitals and to eventually move drug makers and hospitals to a system where most patients will receive their drugs in a single-dose blister pack with a tiny bar code that matches the code on their bracelet.