At first, KDHE tested only for PKU, an inability to metabolize an amino acid. Now, Kansas newborns - there were 39,353 in 2003, the last year for which figures are available - are tested for three additional congenital (existing at birth) diseases and for hearing.

Some blood is collected from the baby's heel and put on filter paper that is sent to KDHE's laboratory, says Wichita pediatrician Philip Cherven, director of pediatric education and associate director of the Via Christi Family Practice Residency Program.

If screening test results are abnormal, the baby's doctor is called and more tests are performed. If they're normal, they're mailed to the doctor, who probably doesn't routinely report them to parents. You can ask about them during a checkup.

Each state determines what to test for. Physician Howard Rodenberg, director of KDHE's Division of Health, said a group that specializes in neonatal metabolic screening will visit Kansas later this summer to make recommendations on whether the state's program is adequate or should be expanded.

If changes are recommended, they would go to the next legislative session for approval and funding, he said.

A parent who wants more testing can seek out a commercial lab; a handful nationwide will perform additional tests, for $25 to $90.

The diseases that Kansas tests for are easily treatable and the most common, Cherven and Rodenberg said. Here's a look at what they are:

_PKU

Phenylketonuria, or PKU, is an inability to metabolize phenylalanine, one of the amino acids. Amino acids are found in proteins, and phenylalanine is in most protein foods, especially milk (including breast milk), cheese and meats.

If phenylalanine isn't metabolized, or broken up, it can build up in the blood, leading to mental retardation.

PKU affects an estimated 1 in every 10,000 to 15,000 babies. It is more common in Caucasians and Native Americans.

It's tested for because giving a PKU baby a diet low in phenylalanine can prevent the brain damage and retardation.

In some cases, the diet can be discontinued once the child is about 12, though some experts say it should be followed for life. A woman with PKU who plans to get pregnant should follow the diet, so it doesn't affect her baby's brain.

_Hypothyroidism

Hypothyroidism means a baby doesn't produce enough thyroxine, a hormone, because he doesn't have a thyroid gland or because it doesn't work properly.

The thyroid hormone controls the body's metabolic rate, and without it, everything slows down. Congenital hypothyroidism can lead to poor growth and mental retardation.

Hypothyroidism occurs in about 1 of every 4,000 births. It is more common in girls and in Hispanic populations.

The treatment is simple: The baby is given the thyroid hormone. It must be taken through life.

_Galactosemia

Galactosemia is another metabolic disorder, in which the baby can't metabolize galactose, a milk sugar.

If galactose builds up in the blood, it can be toxic to the kidneys and liver and can damage the eye. It stunts growth and causes brain damage.

Galactosemia occurs in about 1 of every 50,000 newborns.

The disease is not the same as lactose intolerance, because of the permanent damage that can result. A baby with galactosemia must avoid all milk, including breast milk, and dairy products for life.

_Hemoglobinopathies

Hemoglobinopathies means the presence of abnormal hemoglobin. Hemoglobin is the part of the red blood cells that allows them to carry oxygen to different parts of the body.

The most common abnormality is sickle cell disease. It's a disease that affects African Americans almost exclusively.

Sickle cell disease can't be cured, but if a baby tests positive for it, prophylactic antibiotics can be begun. They help prevent infections; children with sickle cell anemia are more likely to develop pneumococcal pneumonia and other infections if they aren't given antibiotics. The children usually get two doses of penicillin a day until they're 5 or 6 years old.

_Hearing

For a few years now, babies have gotten a hearing test before they leave the hospital.

A small probe is placed in the baby's ear, and sounds are generated to stimulate the cochlea, part of the inner ear. In response, the ear itself generates a very low intensity sound, called the otoacoustic emission, that can be measured. If there is an emission, the infant "passes" the hearing screen. Sometimes, babies "fail" the first screen because their ear canal hasn't cleared but pass a subsequent screening.

If additional tests show a problem, a baby might be fitted with hearing aids and started on speech therapy, to help with speech development.

About 1 in 1,000 babies has some form of congenital hearing loss.

There are no national newborn screening standards. Each state decides what to test for, based on costs, evidence about a condition (its prevalence, its seriousness and whether it can be treated) and other factors.

About half the states screen for 10 or fewer genetic disorders. Kansas screens for four diseases and hearing.

In contrast, Mississippi screens for 40 disorders, more than any other state.

By Karen Shideler