Babies and toddlers who arrive at the ER with an unexplained fever often receive no kind of diagnostic test to get at the source of the high temperature, a new study finds.

Whether that’s a bad or good thing is not clear, according to the researchers.

But in some cases, the study found, ER doctors prescribe antibiotics without testing to confirm whether or not the child has a bacterial infection. And that could potentially lead to antibiotic overuse.

Babies and children younger than three often develop fevers that have no obvious cause. And it’s estimated that fevers account for up to one-quarter of young children’s ER visits.

Fevers in very young infants are considered a sign of a potentially dangerous bacterial infection.

But doctors have long debated how to best manage unexplained fevers in children between the ages of three months and three years, according to Dr. Alan E. Simon, a researcher at the National Center for Health Statistics who led the new study.

Since babies these days get the pneumococcal and Hib (Haemophilus influenza type B) vaccines, the odds of a serious bacterial infection, such as a blood infection, are low. So, at least some experts say, a blood test would usually be unnecessary in a vaccinated child with a fever.

On the other hand, a urine test for the much more common cause of fevers - urinary tract infections (UTI) - might be in order.

But until now, no studies had looked at what’s actually going on in U.S. ERs.

For their study, Simon’s team examined records from a national sample of ERs for 2006 to 2008.

They found that in cases where a child ages three months to three years had a fever with no obvious cause, doctors ordered no diagnostic test 59 percent of the time.

Even among girls with a fever higher than 102.2 degrees Fahrenheit - a group considered at higher risk for UTIs - urine tests were ordered only 40 percent of the time.

Overall, urine tests were done in 17 percent of cases, while blood tests were done in about 20 percent.

That raises the possibility that urine tests were underused, at least in girls, while blood tests were overused, Simon’s team writes.

But, Simon told Reuters Health, it’s not possible to tell for sure.

“Clinical judgment always comes into it,” he explained.

And what guidelines exist are not universal, or necessarily hard-and-fast.

The American Academy of Pediatrics, for instance, used to recommend that all children ages two months to two years with an unexplained fever get a urine test. But its latest guidelines, set this year, leave more room for case-by-case decisions.

Some other experts, meanwhile, recommend that urine tests be done whenever a girl or uncircumcised boy younger than two years, or a circumcised boy younger than six months, has a fever with no known cause (because they are at increased risk of a UTI).

As for treatment, Simon’s team found that ER doctors prescribed antibiotics about a quarter of the time. That included 20 percent of fevers where no diagnostic test was done to confirm a bacterial infection.

That’s consistent, Simon said, with past studies that have pointed to antibiotic overuse - such as antibiotic prescriptions for colds, against which the drugs are useless because colds are caused by viruses and antibiotics work only against bacteria.

But he said it’s not clear how often, in this study, the antibiotics were needless. “We don’t know why people were prescribing them, or what they were prescribing them for,” Simon said.

The researchers did find that children seen in ERs in more-affluent zip codes were more likely to get diagnostic tests than kids in poorer neighborhoods.

“We have no idea why that is,” Simon said. It could be the hospitals, he noted, or something about the patients or families who arrive at the ER.

For parents, Simon said, there’s no universal advice to be given on whether your feverish child should get a urine test, blood test or any other test. “There are particulars of each case that would sway any one practitioner’s decision,” he said.

The broader question, according to Simon, is whether more testing, or less testing, would actually improve children’s care. “We don’t know yet if changes in current practice would lead to better outcomes,” he said.

SOURCE: Pediatrics, online November 21, 2011.