Prediabetes Screening: Testing and Next Steps

Prediabetes is associated with elevated blood sugar levels that are not yet high enough to meet a diagnosis of type 2 diabetes. Besides serving as a stepping stone to diabetes, prediabetes increases a person's chances of developing permanent damage to organs like their kidneys, heart, and eyes.

Screening for prediabetes is essential because detecting the condition early increases your chances of preventing the onset of diabetes and its related complications. This article will review the criteria for when an individual should screen for prediabetes. It will also discuss the three blood test options for detecting prediabetes.

Who Should Get Screened?

The American Diabetes Association (ADA) recommends screening for prediabetes in adults who have a body mass index (BMI) greater than or equal to 25 and exhibit one or more other risk factors.

In individuals without risk factors for prediabetes, the ADA recommends screening begin at age 35.

Risk factors for prediabetes include:

• Having a first-degree relative (e.g., a parent, child, or sibling) with diabetes
• Belonging to a racial or ethnic group that has a high prevalence of type 2 diabetes (e.g., Black, Latino, Native American, Asian American, or Pacific Islander)
• Living a sedentary lifestyle

Other risk factors include having a history of certain medical conditions, including:

• Heart disease
• High blood pressure (hypertension)
• Polycystic ovary syndrome (a condition associated with irregular menstrual cycles, excess hair growth, and infertility)
• High cholesterol

According to the ADA, screening for prediabetes is also recommended for adults with HIV or gestational diabetes (a form of diabetes that starts during pregnancy).

Additionally, children who meet the following criteria should get screened:

• Those who are at least 10 years old or have entered puberty
• Those who are overweight or have obesity
• Those have at least one other risk factor for type 2 diabetes
  

Genetics

Prediabetes has a genetic component, which explains why having a parent or sibling with diabetes is considered a risk factor.

Researchers have discovered at least 70 genes believed to be involved in the manifestation of type 2 diabetes. It's thought that mutations (changes in DNA) in these genes can lead to prediabetes by interfering with the production or function of insulin.

Lifestyle Risk Factors

In addition to the genetic component, unhealthy lifestyle factors also contribute significantly to the development of prediabetes.

These lifestyle factors include:

• Excess weight
• Diets high in red and processed meats, high-fat dairy, sugary drinks and snacks, and fast foods
• Physical inactivity
• Cigarette smoking
  

Symptoms

Regardless of your risk, getting tested for prediabetes is crucial if you are experiencing possible symptoms or signs of elevated blood sugar levels.

Some prediabetes symptoms include:

• Excessive thirst (polydipsia) and hunger (polyphagia)
• Frequent urination (polyuria)
• Unintended weight loss
• Unusual tiredness
• Slow-healing wounds or repeated skin or urinary tract infections
• Numbness or burning of the feet
• Blurry or decreased vision
• Presence of acanthosis nigricans (dark patches of velvety skin on the back of your neck, armpit, or groin)
• Erectile dysfunction
  

A1C Test

The A1C test, also called the hemoglobin A1C test, is one option for identifying prediabetes. This simple blood test measures the average amount of glucose stuck to hemoglobin A for the past three months.

Preparation

There is no special preparation for an A1C test. You do not need to fast.

Procedure

The A1C test is a blood test performed in a laboratory or your healthcare provider's office. It usually involves taking a blood sample from a vein in your arm with a needle. Sometimes, the test is measured with a fingerstick, although the results for that are not as accurate.

If the blood comes from a vein, you will have to take the following steps:

• Your technician or healthcare provider will ask you to sit in a chair and place your arm on an armrest.
• They will then identify a vein and clean the area with an alcohol wipe.
• They will then tie a large rubber band (tourniquet) around your upper arm to help fill the vein with blood.
• They will then place a small needle into your vein. You may feel a brief sting.
• Blood will flow through the needle into an attached tube labeled with your name and date of birth.
• They will then remove the band, followed by the needle.
• They will then apply gentle pressure followed by an adhesive bandage on the area where they drew the blood.
• They will then send the blood sample to a laboratory for testing.

If they perform the test via a finger prick, you will take the following steps instead:

• You will wash and dry your hands.
• The technician will make a small prick into your fingertip with a tiny, pointed lancet device.
• A small amount of blood (a drop or two) will flow into a tube or onto a specially designed test strip.
• The blood sample will go off to a laboratory for testing.

Results

If your A1C level is between 5.7% and 6.4%, your healthcare provider may diagnose prediabetes.

Fasting Plasma Glucose Test

The fasting plasma glucose (FPG) test is a one-step blood test, similar to the A1C test. It measures your blood sugar level when it should be at its lowest.

Preparation

Before this test, you will have to refrain from eating or drinking anything (except water) for at least eight hours.

Procedure

The FPG test takes place in a laboratory or your healthcare provider's office. Like the A1C test, the blood sample is obtained through a needle in a vein in your arm or via a finger prick.

Results

If your FPG level is from 100 to 125 milligrams per deciliter (mg/dL), it indicates prediabetes.

Oral Glucose Tolerance Test

The oral glucose tolerance test (OGTT) is a two-step blood test that measures how your body processes glucose in a fasting and non-fasting state. The OGTT involves checking your blood sugar levels before and two hours after drinking a sugary beverage.

Preparation

Before this test, you will have to abstain from eating or drinking anything except water for at least eight hours.

Procedure

The OGTT test takes place in a laboratory or in your healthcare provider's office. The blood samples are obtained through a needle in a vein in your arm or, less commonly, via a finger prick.

As a two-step blood test, you can expect the following:

• The technician or healthcare provider will obtain an initial blood sample.
• Afterward (and if you are an adult), you will receive a sweet 8-ounce solution to drink containing 75 grams of sugar. Also of note: The dose of sugar for children is based on their weight.
• After drinking the solution, you will wait in the reception area for two hours.
• When two hours are up, they will obtain from you a second blood sample.

Results

Glucose levels between 140 mg/dL and 199 mg/dL indicate prediabetes.

Next Steps

Your healthcare provider will recommend intensive lifestyle changes if you test positive for prediabetes.

These lifestyle changes typically include:

• Losing weight if you are overweight or obese
• Eating a high-fiber diet rich in vegetables, fruits, and whole grains
• Engaging in at least 150 minutes of regular physical activity per week
• Avoiding smoking

In addition to adopting healthy lifestyle habits, your provider may start you on metformin, a prescription medication that helps prevent or delay the development of type 2 diabetes.

Metformin lowers blood sugar levels by decreasing the gut absorption and liver production of glucose. It also improves your cells' sensitivity to insulin.

Summary

Prediabetes is a disease of high blood sugar levels. If left untreated, it can progress to type 2 diabetes and other serious conditions like kidney or heart disease. Unfortunately, many people with prediabetes do not have symptoms, which is why screening is essential.

The American Diabetes Association has set forth various criteria for getting screened. These criteria consider factors like your age, weight, family history, lifestyle, and associated medical conditions. Healthcare providers perform screenings using one of three blood tests—an A1C, fasting plasma glucose, or a two-hour oral glucose tolerance test.

A Word From Verywell

If you or a loved one was recently diagnosed with prediabetes, know that you are not alone. Prediabetes affects 96 million American adults and is projected to affect nearly 366 million individuals worldwide by 2030.

Though prediabetes is a common condition, its diagnosis requires a proactive, take-charge attitude on your part to reverse it. As you care for and work to reverse your prediabetes, be sure to identify unique barriers, stressors, and goals. You may also consider joining a support group, hiring a life coach, or seeing a counselor for further guidance and emotional support.