Could You Have Undiagnosed Diabetes?

Table of Contents
View All
Table of Contents

The Centers for Disease Control and Prevention (CDC) states that 8.5 million people (23% of adults in the United States with diabetes), are walking around undiagnosed. Receiving a diabetes diagnosis can be scary, but early detection and treatment can help prevent complications, and when treated properly, people with diabetes can live long and healthy lives.

Learning how to identify diabetes symptoms and understanding your risk for the disease can help you to distinguish between different types of diabetes, diagnosis, and treatment.

People walking around the city

Marco Bottigelli / Getty Images

Symptoms of Undiagnosed Diabetes

There are many different types of diabetes, but most undiagnosed diabetes cases are likely to be type 2 diabetes, which accounts for 90% to 95% of all diabetes.

The American Diabetes Association (ADA) notes that type 2 diabetes often goes undiagnosed for many years because hyperglycemia (high blood sugar) develops gradually and, during early stages, is frequently not severe enough to be recognized by classic diabetes symptoms.

Prediabetes (or impaired glucose tolerance), the precursor to type 2 diabetes, can take years to develop and be present without symptoms. If there are symptoms, they may be ignored or mistaken.

Type 1 diabetes is an autoimmune disease where the body mistakenly attacks the beta cells of the pancreas, ultimately leading to absolute insulin deficiency. Insulin is the hormone responsible for letting glucose enter the cells so that it can be utilized for energy.

In children, type 1 diabetes symptoms can come on more suddenly, while in adults the symptoms may not present as routinely. Type 1 diabetes in children is often characterized by rapid weight loss, excessive thirst, and urination.

A person with type 1 diabetes who is not treated can develop a very serious condition called diabetic ketoacidosis (DKA). Oftentimes, newly diagnosed type 1 diabetes occurs when a person is experiencing DKA. The ADA states that approximately half of children diagnosed with type 1 diabetes are in DKA.

In adults, the onset of type 1 diabetes can be more variable. They may not present with the classic symptoms seen in children and can experience temporary remission from the need for insulin. While the diagnosis is not always so straightforward, over time it becomes more clear.

People who are pregnant and have not previously had diabetes will usually be screened for gestational diabetes during the second trimester of pregnancy, around 24-28 weeks gestation. Most of the time, people who are diagnosed with gestational diabetes do not have symptoms.

The ADA advises that women who are planning a pregnancy get screened for diabetes if they have risk factors and suggests testing all pregnancy-planners for undiagnosed diabetes. Further, the ADA advises testing pregnant women before 15 weeks if they have risk factors and recommends testing for undiagnosed diabetes at the first prenatal visit, if they have not been screened preconception.

If you have a family history of gestational diabetes, you are at increased risk of developing it. Other risk factors include gestational age, weight, activity level, diet, previous pregnancies, and smoking, to name a few. 

Early screening will help to determine if you are at risk of diabetes. Early diagnosis and treatment can help to slow the progression of the disease and reduce the risk of complications. It is especially important to be aware of symptoms that can be caused by diabetes. These include:

Frequent Urination (Polyuria)

Frequent thirst and frequent urination go hand in hand. When your blood sugars are above normal, the kidneys draw in water from your tissues to dilute the glucose so it can be excreted via the urine.

In addition, your cells will push fluid into the bloodstream to flush out the sugar. During filtering, the kidneys do not reabsorb the fluid and instead excrete it via the urine. The more you urinate, the thirstier you will become.

In children with type 1 diabetes, enuresis (involuntary urination, especially in children at night) can occur in the form of bedwetting. In severe instances, such as diabetic ketoacidosis, people with type 1 diabetes can become severely dehydrated.

Excessive Thirst (Polydipsia)

When blood sugar levels are high, the body compensates by trying to get rid of the excess sugar through the urine. The loss of water and electrolytes increases feelings of thirst and leads to increased fluid intake.

This type of thirst is often referred to as unquenchable. This can become problematic, especially if you choose sugary beverages, such as juice, lemonade, and sweetened iced tea to help quench your thirst. Due to the sugar and carbohydrate content of these beverages, blood sugars can become even more elevated.

Extreme Hunger (Polyphagia)

Excess or extreme hunger is caused by the body’s inability to use sugar as fuel. Normally insulin takes sugar from the blood to the cells to use as fuel or energy. When blood sugars are elevated, sugar remains in the blood instead of being used for energy. This can result in feelings of hunger.

Extreme Fatigue

Having elevated blood sugars can also make you very tired. This is because the food you are eating is not being used as fuel. This can be a result of lack of insulin, insulin resistance, or a combination of both. Fatigue can be a symptom in both type 1 and type 2 diabetes.

Unexplained Weight Loss

Unexplained and often rapid weight loss is a common symptom in type 1 diabetes, particularly in children. If you notice that your child is wetting the bed, drinking and eating more, and losing weight, this cluster of symptoms is very common in type 1 diabetes.

If type 2 diabetes has gone undetected for a long period of time, weight loss can also be a symptom.

Blurred Vision

Diabetic retinopathy can occur long before a diabetes diagnosis is determined. Diabetic retinopathy occurs when the small vessels in the eyes become damaged from excess sugar. This can impact vision, causing blurred vision, which may come and go.

For this reason, the ADA recommends that all people diagnosed with type 2 diabetes have an initial comprehensive eye exam shortly after diagnosis.

Numbness and Tingling in the Feet or Hands

When elevated blood sugar affects the nerves in the hands and feet, it can lead to peripheral neuropathy. The ADA states that about half of people with diabetes have neuropathy and that it is more common in those who have had the disease for many years.

Other Symptoms

Additionally, there are other less common symptoms. Keep in mind that these symptoms are not experienced by everyone, but that they can signal the disease and are worth being aware of:

  • Dry mouth (a sign of dehydration that can result from increased urination)
  • Irritability
  • Dry, itchy skin
  • Skin tags
  • Wounds and cuts that are slow to heal
  • Frequent infections, such as yeast infections or infections in the oral cavity
  • Acanthosis nigricans, which are dark, “velvety” patches of skin on the armpits, groin, neck folds, and over the joints of the fingers and toes (an indicator of high insulin seen most often in Black people and in people with prediabetes or type 2 diabetes)
  • Erectile dysfunction (after years of high blood sugar)

Complications of Undiagnosed Diabetes

Having undiagnosed diabetes means that your body is not metabolizing sugar properly, which leads to elevated levels of sugar in the blood.

Elevated blood sugar can also cause acute conditions, such as diabetic ketoacidosis (more common in people with type 1 diabetes) or hyperglycemic hyperosmolar nonketotic syndrome (more common in people with type 2 diabetes). Both conditions are emergency situations and should be treated right away in a hospital.

When blood sugars are elevated for an extended period of time without being treated, long-term complications will occur. An excess of sugar can affect the small and large vessels in the body, which can cause problems in organs all over the body. Some of these complications include:

  • Retinopathy
  • Nephropathy (diabetic kidney disease)
  • Neuropathy
  • Hyperlipidemia (high levels of fat particles in the blood)
  • Hypertension (high blood pressure)
  • Metabolic syndrome
  • Heart disease
  • Periodontal disease
  • Peripheral vascular disease

These complications can reduce the quality of life.

Multiple conditions often go in hand in hand or contribute to one another. But, with detection and screening, people can receive adequate treatment and reduce the risk of these complications.

People with gestational diabetes can have healthy pregnancies. However, without proper diagnosis and intervention, gestational diabetes can lead to serious conditions, such as birth defects, having an extra-large baby (macrosomia), preeclampsia (high blood pressure), C-section, stillbirth, and hypoglycemia (in the baby).

If you have an increased risk of gestational diabetes or have had gestational diabetes in previous pregnancies, your healthcare provider may test for it during the first visit after confirmed pregnancy. Otherwise, gestational diabetes is usually screened for around 24-28 weeks of gestation.

The ADA offers a 60-second risk assessment screening you can use. Keep in mind that this risk assessment is specifically for prediabetes and type 2 diabetes.

If you have a family history of gestational diabetes, type 1 diabetes, or another form of diabetes and are wondering if you have an increased risk of diabetes, you should discuss your concerns with your primary healthcare professional.

Diagnosing Diabetes

The American Diabetes Association recommends routine screenings for type 2 diabetes for everyone every three years after age 35, and more frequently if symptoms develop or risks change (e.g., weight gain). Routine screenings may be recommended by your healthcare provider if you're under 35 but have certain high-risk factors, like being overweight or obese, a family history of diabetes, heart disease, high blood pressure, a history of gestational diabetes, and/or a sedentary lifestyle.

When a person is in a hyperglycemic crisis or is experiencing classic symptoms of hyperglycemia, a diagnosis of diabetes can be made using a random glucose that is greater than or equal to 200 mg/dL (1.1 mmol/L).

Otherwise, a diagnosis requires two abnormal test results from the same sample or two separate test samples. Diagnostic tests include hemoglobin A1C, fasting plasma glucose, and the two-hour prandial glucose during a 75-gram oral glucose tolerance test. These tests can also be used to assess prediabetes.

Hemoglobin A1C

Everyone has some sugar attached to their hemoglobin, but people with elevated blood sugars have more. The hemoglobin A1C test measures the percentage of your blood cells that have sugar attached to them.

This test can examine your average blood sugar over the course of three months and can be measured using a venous blood draw or a finger stick if your healthcare provider has a point-of-care A1c machine onsite.

A1C should be measured using standards certified by the National Glycohemoglobin Standardization Program (NGSP) and standardized to the Diabetes Control and Complications Trial (DCCT) assay.

There are certain instances when an A1C test may not be valid. These include for people with sickle cell anemia (in which a fructosamine test is warranted), pregnancy (second and third trimesters and the postpartum period), glucose-6-phosphate dehydrogenase deficiency, HIV, and hemodialysis, to name a few.

Reference Range for Hemoglobin A1C
Normal below 5.7%
Prediabetes 5.7% to 6.4%
Diabetes 6.5% or above

Fasting Plasma Glucose

A fasting plasma glucose (FBG) or a fasting blood sugar (FBS) test is defined as a blood glucose test taken after you have not eaten for a minimum of eight hours. This is an easy and inexpensive way of measuring blood sugar.

Blood is drawn from your vein to retrieve a sample. Measurements are based on mg/dL. Remember that if you have eaten within eight hours of the test, the test will not be valid.

Reference Range for Fasting Plasma Glucose
Normal less than 100 mg/dl
Prediabetes 100 mg/dl to 125 mg/dl
Diabetes 126 mg/dl or higher

Glucose Challenge

The glucose challenge is part one of a two-step approach in diagnosing gestational diabetes in pregnancy. You do not need to fast for this test. You will ingest 50 grams (g) of a sugary drink during the test, and your blood will be drawn after one hour.

If your blood sugar is elevated (greater than 140 mg/dl), you will need to return for an oral glucose tolerance test. This glucose tolerance test will consist of ingesting 100 g of a glucose drink and having your blood sugar tested at one, two, and three hours.

You will need to fast for the second test. If two or more values on the 100-g test meet or exceed the thresholds below, a gestational diabetes diagnosis is made:

Reference Range for Three-Hour Oral Glucose Tolerance Test for Gestational Diabetes
Normal Abnormal
Fasting less than 95 mg/dl 95 mg/dl or greater
1 hour   less than 180 mg/dl 180 mg/dl or greater
2 hour   less than 155 mg/dl 155 mg/dl or greater
3 hour   less than 140 mg/dl 140 mg/dl or greater

Oral Glucose Tolerance Test

An oral glucose tolerance test with 75 g of glucose can measure your glucose tolerance to a standard glucose load. This is a two-hour test where you will drink a sugary beverage and your blood sugar will be measured at the two-hour mark. You need to fast for this test.

This test tells the healthcare provider how your body processes sugar. You’ll often hear of impaired glucose tolerance (IGT) in people with prediabetes when blood sugars are high, but not quite high enough to diagnose diabetes. This is common in people who have insulin resistance.

An oral glucose tolerance test using 75 g is also a one-step approach to diagnosing gestational diabetes. During this test, a pregnant person has their fasting blood sugar tested and then tested again at hours one and two.

Abnormal results include a fasting blood sugar of 92 mg/dl or more, one-hour 180 mg/dl or more, and two-hour 153 mg/dl or more.

Reference Range for Oral Glucose Tolerance Test (Non-Pregnant)
Normal less than 140 mg/dl
Prediabetes 140 mg/dl to 199 mg/dl
Diabetes 200 mg/dl or higher

Random Glucose Test

This test can be used to diagnose diabetes when you have severe symptoms. If your blood sugar is greater than 200 mg/dl and you have symptoms, a diabetes diagnosis is made.


A C-peptide test is used to measure pancreatic insulin function. This determines whether a person’s pancreas is secreting sufficient insulin and is used as a tool in diagnosing type 1 diabetes.

Glutamic Acid Decarboxylase (GAD)

GAD is an important enzyme that helps your pancreas to function properly. When the body makes GAD autoantibodies, it can disrupt the the ability of the pancreas to do its job. A GAD, GADA, or anti-GAD test may be ordered to determine what type of diabetes you have.

The presence of GAD autoantibodies usually means that your immune system is attacking itself and can lead to a type 1 diabetes diagnosis or a LADA diagnosis.

Insulin Assays

Some researchers believe that using insulin assays to diagnose diabetes and prediabetes may help to increase the ability to detect the disease and, as a result, allow for earlier intervention. Insulin assays can assess fasting insulin and postprandial (after meal) insulin.

However, this is not a common test used to diagnose diabetes and is most often used to determine low blood sugar, insulin resistance, and to diagnose an insulinoma.


For people with a genetic predisposition to type 1 diabetes, screening for autoantibodies is recommended in the setting of a research trial.

Some of these autoantibodies include islet cell autoantibodies and autoantibodies to insulin (IAA), glutamic acid decarboxylase (GAD, GAD65), protein tyrosine phosphatase (IA2 and IA2β), and zinc transporter protein (ZnT8A).

In some instances, these could be detected in the serum of people at risk for type 1 diabetes months or years before the onset of the disease. Identifying these autoantibodies and educating those at risk about symptoms may help diagnose and treat type 1 diabetes earlier. This typically takes place in the research setting.


Treatment of diabetes will depend on the type of diabetes that is diagnosed, age at diagnosis, the severity of hyperglycemia, and whether you have other health conditions.

For this article, we will talk about type 1, type 2, and gestational diabetes treatment. Other forms of diabetes, such as neonatal diabetes and maturity-onset diabetes mellitus of the young (MODY), are treated differently.

Type 1 Diabetes

Insulin deficiency in type 1 diabetes will require you to take insulin in the form of infusion or injection multiple times a day to keep blood sugars within normal range and prevent serious complications.

If you are diagnosed and in DKA, you will receive treatment in the hospital to correct high blood sugar and acidosis. You will receive volume repletion and prevention of hypokalemia (low potassium), in addition to intravenous insulin.

With advancements in technology, people with type 1 diabetes have many treatment options, including insulin pumps, closed-loop systems, and continuous glucose monitors that help to track, manage, and alert a person when their blood sugar is going up or down.

This does not mean that managing type 1 diabetes is easy, but newer technology can help to reduce the burden. The type of treatment you will be placed on will depend on your age, lifestyle, preferences, and understanding.

Insulin delivery and blood sugar monitoring are part of the treatment regimen. You will also have to understand how to count carbohydrates, where they come from, and how they impact your blood sugars.

Exercise can also play a role in blood sugar management. Understanding how your body responds to exercise and stress will be an important part of the treatment process.

Maintaining regular appointments with your endocrinologist and diabetes team will be important for assessing your health and making sure you are receiving continuous education for quality of life and to prevent complications.

For children who are newly diagnosed with type 1 diabetes, some experience a “honeymoon” period when the pancreas is still able to produce enough insulin to reduce (or even eliminate) insulin needs. The length of time this lasts is variable; it can last a week, months, or possibly years.

It is important to note that in type 1 diabetes, this is a temporary phase and eventually insulin therapy will need to be restarted or increased.

Type 2 Diabetes

The way type 2 diabetes will be treated will depend on the person. Individualized treatment plans should consider a person’s blood glucose at diagnosis, age, weight, lifestyle, culture, and other health conditions.

Type 2 diabetes treatment will require lifestyle intervention, including dietary and exercise education. Oftentimes, weight loss is indicated, and a modest weight reduction, around 10% of original body weight, can help improve blood sugars.

Depending on where a person’s blood sugars are at diagnosis, they may also need to include diabetes medications, such as oral medicines, non-insulin injectables, or insulin, in their treatment plan to get their blood sugars stabilized. When treating a person with diabetes, it is important to consider their lifestyle.

There are different classes of medications that are capable of lowering blood sugars. Some medications can also help people with diabetes lose weight and improve other areas of health, including cardiovascular health.

When blood sugars are very high at diagnosis, people with diabetes may be prescribed several medications to get their blood sugars under control. It is possible to reduce or omit medications if lifestyle interventions are successful.

For example, if an overweight person with type 2 diabetes is placed on medicine and then begins walking, changes their diet, and loses weight, they may be able to reduce or stop their medication.

Gestational Diabetes

If you have been diagnosed with gestational diabetes, you will likely be referred to a registered dietitian and certified diabetes care and education specialist for medical nutrition therapy and diabetes self-management education.

Most of the time, you’ll be able to get your blood sugars to your goal using a modified carbohydrate diet that is rich in fiber, protein, and healthy fat.

Sometimes diet is not enough, and you will need insulin to control your blood sugar. This does not mean that you have done anything wrong. Rather, your body needs some help to get your blood sugars down.

Tight blood sugar control will be important in protecting the health of you and your baby. Your medical team will educate you on blood sugar testing and blood glucose goals.

Gestational diabetes usually goes away after the baby has been born. The ADA recommends that all people who had gestational diabetes be tested for prediabetes and diabetes at 4-12 weeks postpartum, using the 75-g oral glucose tolerance test and clinically appropriate non-pregnancy diagnostic criteria.

The ADA also recommends that all people with a history of gestational diabetes have lifelong screening for the development of diabetes or prediabetes every three years.

If you receive a diagnosis of prediabetes after gestation, lifestyle intervention will be recommended, including a healthy diet, exercise, stress management, and weight management (when indicated).

Other Forms of Diabetes

There are other forms of diabetes, such as neonatal diabetes, monogenic diabetes, steroid-induced diabetes, and type 2 diabetes in children. These types of diabetes may have different diagnostic and treatment regimens depending on age and whether you have any other health conditions.

A Word From Verywell

Part of the reason that millions of Americans have undiagnosed diabetes is that the condition can often be silent for many years with no symptoms. But non-invasive screening methods can be used to assess risk, and more people can be tested based on their risk factors.

The diagnostic tests are relatively easy and, if diagnosed, diabetes can be treated and managed. Although it might be scary to receive a diabetes diagnosis, early detection and treatment can reduce, prevent, and in certain instances reverse the complications of diabetes.

Do not be afraid to take control of your health. You can make long-lasting changes today.

18 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. American Diabetes Association. National diabetes statistics report.

  2. American Diabetes Association. 2. Classification and diagnosis of diabetes: Standards of medical care in diabetes—2022. Diabetes Care. 2022;45(Supplement 1):S17-S38. doi:10.2337/dc22-S002

  3. American Diabetes Association. 15. Management of diabetes in pregnancy: Standards of medical care in diabetes—2022. Diabetes Care. 2022;45(Supplement 1):S232–S243. doi:10.2337/dc22-S015

  4. Kleinberger JW, Maloney KA, Pollin TI. The genetic architecture of diabetes in pregnancy: implications for clinical practiceAm J Perinatol. 2016;33(13):1319-1326. doi:10.1055/s-0036-1592078

  5. Kharroubi AT, Darwish HM. Diabetes mellitus: the epidemic of the centuryWorld J Diabetes. 2015;6(6):850-867. doi:10.4239/wjd.v6.i6.850

  6. Solomon SD et al. Diabetic retinopathy: a position statement by the American Diabetes Association. Diabetes Care. 2017;40(3):412-418. doi:10.2337/dc16-2641

  7. American Diabetes Association. Understanding neuropathy and your diabetes.

  8. Ramachandran A. Know the signs and symptoms of diabetesIndian J Med Res. 2014;140(5):579-581.

  9. National Institute of Diabetes and Digestive and Kidney Diseases. How do doctors diagnose gestational diabetes?

  10. Garrison A. Screening, diagnosis, and management of gestational diabetes mellitus. Am Fam Physician. 2015;91(7):460-467. PMID: 25884746

  11. American Diabetes Association. Diagnosis.

  12. Towns R, Pietropaolo M. GAD65 autoantibodies and its role as biomarker of type 1 diabetes and latent autoimmune diabetes in adults (LADA)Drugs Future. 2011;36(11):847. doi:10.1358/dof.2011.036.11.1710754

  13. DiNicolantonio JJ, Bhutani J, OKeefe JH, Crofts C. Postprandial insulin assay as the earliest biomarker for diagnosing pre-diabetes, type 2 diabetes and increased cardiovascular risk. Open Heart. 2017;4(2):e000656. doi:10.1136/openhrt-2017-000656

  14. Lab Tests Online. Insulin.

  15. Westerberg DP. Diabetic ketoacidosis: evaluation and treatment. Am Fam Physician. 2013;87(5):337-346.

  16. Moole H, Moole V, Mamidipalli A, et al. Spontaneous complete remission of type 1 diabetes mellitus in an adult - review and case reportJ Community Hosp Intern Med Perspect. 2015;5(5):28709. doi:10.3402/jchimp.v5.28709

  17. American Diabetes Association. Type 1 diabetes.

    1. Grams J, Garvey WT. Weight loss and the prevention and treatment of type 2 diabetes using lifestyle therapy, pharmacotherapy, and bariatric surgery: mechanisms of actionCurr Obes Rep. 2015;4(2):287-302. doi:10.1007/s13679-015-0155-x

By Barbie Cervoni MS, RD, CDCES, CDN
Barbie Cervoni MS, RD, CDCES, CDN, is a registered dietitian and certified diabetes care and education specialist.