A significant number of children and young adults with diabetes may not be getting the routine tests recommended for managing the disease, according to a study out Monday.

Researchers found that of more than 1,500 young people with either type 1 or type 2 diabetes, about one-third had not undergone eye exams or had tests of long-term blood sugar control as recommended by the American Diabetes Association (ADA).

According to ADA guidelines—the main ones doctors follow for managing diabetes—children and young adults with the disease should have a hemoglobin A1C test at least twice a year (or three times if they are on insulin).

The blood test gives a snapshot of a person's blood sugar control over the past few months, and is considered key in managing diabetes long term. In this study, 32 percent of kids and young adults were not getting the test as often as the ADA advises.

A similar number, 34 percent, were not getting eye exams as recommended; the ADA says those should be done once a year in everyone with type 2 diabetes, and in anyone who has had type 1 diabetes for at least five years and is at least 10 years old.

Diabetes can damage the blood vessels of the eyes, even in young people, and regular eye exams are considered key to spotting and treating those problems early.

ADA recommendations are the most widely used guidelines for treating diabetes, said Beth Waitzfelder, an investigator at the Kaiser Permanente Center for Health Research in Honolulu who led new study.

It's not clear why some young people were not getting all the suggested tests. But the research offers some clues, according to Waitzfelder.

In general, she told Reuters Health in an email, older teenagers and young adults were less likely than younger kids to be compliant.

That may be because they're not as vigilant with their diabetes care as their parents were, Waitzfelder speculated. Or it could be lack of insurance, or a change in doctors, she said.

Children from low-income families were also less likely to get all the recommended tests. Those whose families made upwards of $75,000 a year were about 65 percent more likely to have had the tests as those whose families made less than $25,000.

That was with insurance coverage taken into account. "Even among individuals with diabetes who have insurance," Waitzfelder said, "we know that the co-payments for healthcare services, medications and diabetes supplies can be difficult for some families to manage."

The results, reported in the journal Pediatrics, are based on surveys of 1,514 U.S. children, teenagers and young adults.

Most—85 percent—had type 1 diabetes, which is caused by an abnormal immune system attack on the pancreas cells that make the blood-sugar-regulating hormone insulin. The rest had type 2 diabetes, in which the body's ability to use insulin to control blood sugar is impaired.

The group was doing fairly well when it came to certain ADA-recommended tests. Nearly all—95 percent—got regular blood pressure checks, while 88 percent had had their cholesterol checked at least once (or once a year if they were 18 or older).

When it came to tests of kidney function, 83 percent were getting them as often as the ADA recommends. Diabetes can eventually lead to kidney disease, so yearly urine tests are suggested—starting at age 10 for children who've had type 1 diabetes for at least five years.

"It is important for parents and youth with diabetes to be aware of these guidelines," Waitzfelder said.

She suggested that they learn more about the recommendations from the ADA or other groups, like the Juvenile Diabetes Research Foundation International. Then they can bring any questions to their doctors.

In this study, children and young adults who were seeing an endocrinologist, doctors whose specialty includes diabetes care, were more likely to have received all the recommended tests compared with their counterparts seeing a "generalist" doctor.

So it's possible, Waitzfelder said, that generalists are less aware of the ADA guidelines than endocrinologists are.