New research suggests a shocking number of Americans have diabetes but have never been diagnosed.

About 8 million people are believed to have undiagnosed diabetes in the U.S., and among those who have been diagnosed only one-quarter met important health goals, a news release reported.

Among these crucial health goals were managing blood sugar, blood pressure, and cholesterol levels.

"Out of 28.4 million people with diabetes, more than a quarter don't know [it]," said study author Dr. Mohammed Ali, an assistant professor of public health at Emory University School of Medicine in Atlanta. "About 80 percent of those people are linked to a health care provider, and two-thirds are seeing them twice a year or more. So, through whatever means, they aren't being identified with diabetes."

The majority of cases seen in the study were Type 2 diabetes, which causes the body to use the hormone insulin inefficiently. Symptoms of this condition can include: "fatigue, blurred vision, slow-healing cuts and scrapes, and the need to urinate more often." Despite increased awareness of the condition, diabetes is still a major cause of death and disability in the U.S.

To make their findings the researchers used a concept called "cascade of care," which is a way of looking at how people living with a certain condition are cared for and what kind of treatments they receive. The team looked at a survey of 30,000 adults and determined nearly three out of every 10 people in the U.S. with diabetes do not receive a proper diagnosis.

In those who were diagnosed, only 64 percent met their blood sugar goals, and 66 percent had controlled blood pressure; a mere 57 percent of diabetes patients met their goal of keeping "bad" cholesterol levels down.

The results also suggest 84.5 of those who remain undiagnosed report they had visited a regular health care provider, and 66.5 reported at least two visits in the past year.

"The fact that they go to the doctor rings alarm bells. We're missing out on a whole lot of opportunities," Ali said. "The answer isn't simple, but we need to identify where the gaps are. Is it high demand on physicians? Is it a system-wide problem? There are a lot of things that could be going on. It probably won't be just one specific thing." 

The findins were published in a recent edition of the Annals of Internal Medicine.