ATLANTA (AP) _ Using names rather than codes is a more reliable way to count cases of HIV, the government said Thursday.

Instead of listing patients by name, health officials in Maryland and Texas came up with a system in 1994 that uses a code to identify them. The code is a 12-digit number that uses the person's Social Security number, date of birth and other digits to represent gender and race.

But the Centers for Disease Control and Prevention said a three-year evaluation of the two systems found that the codes often were incomplete, making it difficult to link them to real people.

Since 1981, states have kept track of AIDS cases by name, but because deaths and new cases of the disease have dropped off, the government is putting more emphasis on the need for thorough reporting of HIV cases.

At the start of the year, 31 states tracked HIV cases by name, along with their AIDS cases.

The CDC said reporting by name is an efficient and accurate way to monitor HIV cases. But the agency said it still supports anonymous testing as an important means of prevention.