What Are Tests for Prediabetes?

Prediabetes is a condition characterized by mildly elevated blood sugar. If left untreated, prediabetes can increase the risk of developing type 2 diabetes. About 96 million American adults have prediabetes.

Often, there are no clear warning signs or symptoms of prediabetes. So screening is important if you’re at risk. Fortunately, prediabetes usually can be reversed with lifestyle modifications, including monitoring blood sugar levels, diet changes, and exercise. 

This article will discuss the risk factors for prediabetes and the screening tests that uncover this serious condition, as well as ways to reverse its course.

Prediabetes bloodwork

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What Is Prediabetes?

Prediabetes is an early warning sign that you may be headed towards full-blown type 2 diabetes. Prediabetes means you have a higher than normal blood sugar (glucose), but not high enough to be considered a type 2 diabetic.

Causes and Risk Factors

The bodies of people who are diabetics either can't make enough insulin or can’t use the insulin they do make as well as they should. The reasons for this remain a mystery, but excess weight and a lack of physical activity appear to be major contributors. Genetics and poor eating habits are suspects, too.

Without treatment, it's likely that you will develop type 2 diabetes. In fact, studies show that if you are diagnosed with prediabetes, you have up to a 50% chance of developing diabetes over the next five to 10 years.

The risk factors for diabetes include:

  • Elevated waist-to-hip ratio (an indicator of obesity, as indicated by a waist circumference over 32 inches for women and 40 inches for men)
  • Living a sedentary lifestyle
  • Having a family history of diabetes, especially a parent, brother, or sister with the disease
  • Having a history of diabetes during pregnancy, also known as gestational diabetes, or giving birth to a baby who weighed more than 9 pounds
  • Having polycystic ovary syndrome (PCOS)

Insulin Takes Center Stage

In prediabetes, your cells become resistant (or less sensitive) to insulin, making it more difficult for sugar to be moved from the blood to your cells.


Technically, prediabetes is not diabetes, so it often goes undiagnosed. Still, an estimated 96 million adults have prediabetes in the U.S. This is roughly 38% of all adults in America.

Men are slightly more likely to have prediabetes than women. The prevalence of prediabetes is similar among all racial/ethnic groups.

Medical History

Prediabetes is more likely in those who struggle to maintain a healthy weight, do not participate in routine exercise, or have a personal history of gestational or family history of type 2 diabetes. Prediabetes, like diabetes, may also be associated with other medical conditions, such as high blood pressure, heart disease, and high cholesterol.

If your healthcare provider suspects that you have prediabetes, they may ask questions about your family and medical history, including:

  • Does anyone in your family have a history of type 2 diabetes or heart disease?
  • Have you ever had gestational diabetes?
  • What medicines are you taking?
  • Have you been diagnosed with high blood pressure (hypertension), high cholesterol, or both?
  • Have you experienced irregular menstrual cycles or been diagnosed with polycystic ovary syndrome?

Family History

If you have a first-degree relative with diabetes (such as your mother, father, sister, or brother), you are more likely to get diabetes yourself. You are also more likely to have prediabetes. 

Learning about your family health history is an important step in identifying your risk of developing diabetes and may prompt you to get screened for prediabetes. However, a family history of prediabetes does not mean that you will experience the same fate. Many people prevent or delay prediabetes and type 2 diabetes by eating healthier, being physically active, and maintaining a healthy weight.

One way to make sure you stay on track is to elicit the help of a diabetes care team. Discussing your family history of diabetes with a healthcare professional can help you formulate a plan to prevent or delay diabetes, as well as reverse prediabetes if you have it.

Diagnosis: Blood Tests for Prediabetes

Prediabetes is an intermediate stage before full-blown type 2 diabetes that needs to be identified and addressed immediately. Any of the following results will confirm a diagnosis of prediabetes:

  • Hemoglobin A1C: An A1C blood test determines your average blood sugar levels over a three-month period. If your A1C levels are between 5.7% and 6.4%, you have a diagnosis of prediabetes.
  • Fasting plasma glucose: This blood test measures your blood sugar levels after not having anything to eat or drink (except water) for at least eight hours before the test. A fasting blood sugar level from 100 to 125 mg/dL denotes impaired fasting glucose and is therefore considered prediabetes.
  • Oral glucose tolerance test (OGTT): The OGTT is a two-hour test that checks your blood sugar levels before and two hours after you drink a special sweet drink. Levels between 140–199 mg/dL signal impaired glucose tolerance and prediabetes.

When to Get Tested

You can have prediabetes for years with no clear symptoms. The American Diabetes Association recommends regular screening for prediabetes starting at age 35. If you have a family history of diabetes, you may want to consider getting screened for diabetes sooner.

If you're feeling the following symptoms, you may want to get tested for diabetes:

  • Increased hunger
  • Increased thirst
  • Unexpected weight loss
  • Frequent urination
  • Sudden changes in vision
  • Extreme fatigue
  • Poor wound healing

Early diagnosis and treatment are key to halting the progression of prediabetes. The longer you wait, the greater the risk of serious complications, like heart or kidney disease or vision loss.

If left untreated, high blood sugars can damage organs throughout the body over time, underscoring the need to take immediate action if you have any concern that your symptoms might be caused by prediabetes or type 2 diabetes. 

Remember that prediabetes means your body is not producing enough insulin or the insulin does not work properly. Still, your high blood sugar levels have not yet begun to damage your organs, which is a major complication of type 2 diabetes.

Can You Reverse Prediabetes?

The first step in preventing the progression of prediabetes is to lead a healthy lifestyle. The sooner you implement lifestyle changes, the more you'll increase your chances of staving off diabetes.

Even prior to getting a formal diagnosis, it's important for any at-risk person to take a CDC risk assessment and adopt healthy lifestyle changes, including weight loss, regular and moderate-intensity exercise, and a balanced diet consisting of fruits and vegetables.


Prediabetes is an intermediate stage before type 2 diabetes that can be halted and reversed with early diagnosis and treatment. You can have prediabetes for a long time without showing symptoms, so it's imperative to calculate your risk using the CDC assessment tools.

If you suspect that you have prediabetes or type 2 diabetes, a healthcare provider can confirm the diagnosis via a number of low-cost blood tests.

Frequently Asked Questions

  • How common is prediabetes?

    Prediabetes is common in the United States and around the world. About 96 million American adults—more than one in three adults under age 65 and 50% of people over age 65—have prediabetes. Moreover, eight out of 10 people with the condition don’t even know they have it since prediabetes often has no symptoms. So prediabetics may be undercounted.

  • What are the symptoms of prediabetes?

    Often, the symptoms include:

    • Increased hunger
    • Increased thirst
    • Unexpected weight loss
    • Frequent urination
    • Sudden changes in vision
    • Extreme fatigue
    • Poor wound healing
  • Should you avoid certain foods if you're prediabetic?

    If you have prediabetes, you can halt and even reverse the disease by maintaining a healthy weight, exercising regularly, and eating nutritious foods. There is no one food to avoid, but limiting processed foods like cookies and candy, sugary drinks like soda and fruit juices, and junk food can go a long way in helping you stave off type 2 diabetes.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. Prevalence of prediabetes among adults.

  2. Centers for Disease Control and Prevention. National diabetes prevention program

  3. ElSayed NA, Aleppo G, Aroda VR, et al. 2. Classification and diagnosis of diabetes: Standards of care in diabetes—2023. Diabetes Care. 2023;46(Suppl 1):S19-S40. doi:10.2337/dc23-S002

  4. Zimmermann LJ, Thompson JA, Persell SD. Electronic health record identification of prediabetes and an assessment of unmet counselling needs. J Eval Clin Pract. 2012;18(4):861-865. doi:10.1111/j.1365-2753.2011.01703.x.

  5. Kaiser Permanente. Prediabetes: medical history and physical exam

  6. National Institute of Diabetes and Digestive and Kidney Diseases. Recommended tests for identifying prediabetes.

By Shamard Charles, MD, MPH
Shamard Charles, MD, MPH is a public health physician and journalist. He has held positions with major news networks like NBC reporting on health policy, public health initiatives, diversity in medicine, and new developments in health care research and medical treatments.