Signs of Diabetes: What the Symptoms Mean

Talk to your doctor if you have any of these concerns.

Fatigue is one of many potential symptoms seen in a diabetes patient.

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Many of the same symptoms can be seen in people with type 1, type 2, and gestational diabetes; however, people with type 1 diabetes tend to have more severe and more sudden-onset symptoms. Conversely, some people with type 2 symptoms may have few or no signs of diabetes, particularly in the early stages of the disease.

  • Frequent urination
  • Increased thirst
  • Increased hunger
  • Fatigue
  • Blurry vision
  • Slow-healing cuts or bruises
  • Increased infections, particularly skin, vaginal, or gum infections
  • Dry skin

Patients with type 1 diabetes may additionally experience weight loss, despite having an increased appetite and eating more.

Patients with type 2 diabetes may develop a velvety darkening of the skin on the back of their necks and in their armpits, called acanthosis nigrans. Type 2 diabetics may also experience numbness or tingling in their hands or feet.

If you are experiencing any of the classic signs of diabetes, your doctor or healthcare provider will order a diabetes test. However, since some people with type 2 diabetes do not experience any signs of diabetes initially, the American Diabetes Association (ADA) has recommended that all people over the age of 45 have their blood glucose level tested every three years.

Testing Info

The ADA also recommends that any person who has a body mass index (BMI) of 25 and at least one additional risk factor (family history, low HDL cholesterol, high triglycerides, smoking, African-American/Asian-American/Native American/Hispanic ethnicity, sedentary lifestyle, polycystic ovarian disease, history of gestational diabetes, high blood pressure, etc.) be screened. Tests typically used:

A1C Test: When glucose is in the blood, it attaches to the oxygen-carrying substance, hemoglobin, forming what scientists call “glycated hemoglobin.” The percentage of glycated hemoglobin or percentage of hemoglobin with blood glucose attached can be measure by the A1C test and that amount reflects your average blood glucose over the past two to three months.

The higher your blood glucose levels have been, the higher your A1C will be. An A1C less than 5.7 percent is normal. An A1C between 5.7 and 6.4 percent likely means you will be diagnosed with pre-diabetes, a disease of insulin resistance resulting in blood glucose levels that are elevated but not high enough to be considered diabetes. An A1C of 6.5% or higher means you have diabetes.

Random Plasma Glucose Test: This is a blood/plasma test administered any time of the day , regardless of when you last ate, measuring your level of glucose. Diabetes is diagnosed with any random blood glucose result of 200 milligrams per deciliter (mg/dl) or higher.

Fasting Plasma Glucose Test (FPGT): Just as the name applies, this is a blood/plasma test administered when you have been fasting (for at least 8 hours), measuring your level of glucose. A fasting blood glucose test less than 100mg/dl is considered normal. A fasting blood glucose level between 100 and 125mg/dl is considered to be prediabetes. A fasting blood glucose level of 126 mg/dl or higher means you have diabetes.

Oral Glucose Tolerance Test (OGTT): This test involves fasting for eight hours after which your blood glucose level is measured. You then drink a special solution containing 75 grams of glucose and your blood glucose level is measured again two hours later. This test can be used for all forms of diabetes and has been shown to be more sensitive than the FPGT; however, it is more time consuming and, thus, less convenient. This is the primary test obstetricians use for testing pregnant women for gestational diabetes and is typically administered between the 24th and 28th week of pregnancy. In some cases, an obstetrician will first administer a glucose challenge test where the mother will drink a glucose solution and have her glucose level checked one hour later. If it is abnormal, she will then be scheduled for an OGTT.

A two-hour blood glucose level less than 140mg/dl is normal. An individual is diagnosed with prediabetes if their two-hour blood glucose level is between 140 and 199 mg/dl. Diabetes is diagnosed when the two-hour blood glucose level is 200 mg/dl or higher.


Originally published May 2016.


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Helen Boehm Johnson, MD

Helen Boehm Johnson, MD, is a medical writer who brings the experience of a residency-trained physician to her writing. She has written Massachusetts General Hospital’s Combating Memory Loss report (2019, 2020, … Read More

View all posts by Helen Boehm Johnson, MD

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