VA Research Reveals Routine Blood Tests Could Someday Predict Diabetes

Jul 20, 2019 | Diabetes Detection, Prediabetes


A large Veterans Affairs research study, including several VA systems, reveals that levels of glucose could be used to predict which patients will develop diabetes.

With the results appearing in the July 19, 2019 issue of PLOS ONE, the findings could lead ultimately to earlier treatment options and better outcomes.

The Study

The American Diabetes Association recommends testing for diabetes using a few different methods: a fasting glucose level, an oral glucose tolerance test (which requires fasting and ingestion of a glucose load), a HgbA1c level (a measure of average blood glucose levels over the previous two to three months), or a random plasma glucose when accompanied by symptoms caused by high glucose levels. Random plasma glucose of 200 mg/dL (milligrams per deciliter) or higher is usually the threshold for a diagnosis of diabetes. It can be done at any time and does not require fasting or withholding meals.

These tests are frequently included in routine labwork patients undergo during or after outpatient medical appointments. However, since many patients are not fasting when they get their blood drawn, routine blood tests with random glucose levels below 200 mg/dL have not previously been deemed useful for diabetes screening.

VA researchers examined data on these routine blood tests to see whether random plasma glucose levels could in fact predict which patients would develop diabetes in the future. They studied data on more than 900,000 VA patients who were not already diagnosed with diabetes. All patients had at least three random plasma glucose tests during a single year. Most of these tests were likely obtained “opportunistically”–that is, during regular doctor visits not specifically related to diabetes screening.

Over a five-year follow-up, about 10% of the total study group developed diabetes. Elevated random plasma glucose levels, though not meeting the diagnostic threshold for diabetes, accurately predicted the development of diabetes within the following five years. Patients with at least two random plasma glucose measurements of 115 mg/dL or higher within a 12-month period were highly likely to be diagnosed with diabetes within a few years. Glucose levels of 130 mg/dL or higher were even more predictive of diabetes.

As expected, demographics and risk factors are known to be related to diabetes also predicted the development of the disease. Demographic factors included age, sex, and race. Other risk factors that predicted diabetes included a high body mass index (BMI), smoking, and high cholesterol. However, random plasma glucose tests were stronger predictors of diabetes than demographics or other risk factors, alone or combined.


A major health crisis in the United States, yet still over 7 million Americans with diabetes go undiagnosed reports the Centers for Disease Control and Prevention. Early diagnosis allows the use of lifestyle changes or medications that could help prevent or delay the progression from prediabetes to diabetes and help keen diabetes from worsening. Delaying the diagnosis of diabetes-related complications could develop before treatment starts.

Lead Research/Investigator

Dr. Mary Rhee, lead author, physician, Atlanta VA Health Care System, and Emory University


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