Starting Out - 101 Series

101 Guide - Testing for Diabetes

Reviewed by

Shifa Fathima

Diabetes is often known as the Silent Killer since it is often symptomless and only starts showing when the condition has already progressed to a large extent. Another reason is that it does not manifest as a single illness, but instead affects a lot of your body systems leading to several other disorders and comorbidities. This critical nature of diabetes is what makes it necessary to be able to diagnose the condition early so that its onset can be delayed or prevented altogether. Hence, the key to staying healthy is to get screened for diabetes or tested at regular intervals and always stay one step ahead of the condition. Lets start by first seeing who should get tested.

Who should get tested?

        1. Based on Early Warning Signs & Symptoms (One or more of the below)

  • Extreme thirst
  • Excessive hunger
  • Frequent urination
  • Tiredness
  • Blurred Vision
  • Delayed healing of cuts or wounds

        2. Based on Risk Factors & Red Flags (Any of the below)

  • Age >40 years
  • Being Obese or Overweight with excessive fat in and around the abdomen (Belly Fat)
  • Waist Size more than 40 inches in Men and 35 inches in Women
  • Family history of Diabetes
  • History of Cardiovascular conditions
  • Women diagnosed with Gestational Diabetes or Polycystic Ovarian Syndrome (PCOS)

Why should you get tested?

  • Diabetes cannot be cured, but it can be reversed and managed if detected early. If it is diagnosed at a later stage or poorly managed, it can lead to further complications of diabetes mellitus like cardiovascular disease, retinopathy, diabetic foot, pregnancy complications, kidney diseases and neuropathy.
  • Testing for individuals with Diabetes helps to plan, manage and maintain blood glucose levels below a specific limit to avoid damage to other vital organs. If it is left untreated, the high sugar levels in the blood can lead to serious consequences where even medications may not be effective.
  • Testing is crucial even for individuals with Prediabetes, since there is a chance to reverse this health condition or delay its progression to diabetes if diagnosed in time.
  • Being diagnosed with diabetes can have a strong emotional impact on you and your family. Positive thinking and learning about your condition will lead to lifestyle changes that are imperative for diabetes management
  • Having awareness about your blood glucose levels and measures to control them will not only help you in managing your diabetes effectively, but also to lead a long, healthy and disease-free life.

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What are the Tests Available?

Now that you know why testing is so important, let's take a look at the different tests available for diagnosing diabetes.

1. Fasting Blood Sugar (FBS) Test

In this test, blood samples are collected, usually in the morning after fasting overnight. Following an overnight fast, a blood sample will be collected. Fasting blood sugar normal range is less than 100 mg/dL (5.6 mmol/L). Prediabetes is defined as fasting blood sugar levels ranging from 100 to 125 mg/dL (5.6 to 6.9 mmol/L). You have diabetes if your blood sugar level is 126 mg/dL (7 mmol/L) or greater on two independent tests.

2. Post-Prandial Blood Sugar (PPBS) Test

Post-Prandial blood glucose levels are measured 2 hours after eating a meal. The postprandial test is usually performed two hours after eating a meal. The time for the same starts with the beginning of the meal. Blood sugar levels in healthy people normally return to normal within 2 hours, but in people with diabetes, they may stay elevated. As a result, it acts as a last test for people who may have diabetes, as well as if the person with diabetes is able to control his blood sugar levels. The normal blood sugar level for this test is 100–140 mg/dl.

3. Glycated Hemoglobin (A1C) Test

A1C measures the glucose amount carried in the hemoglobin accumulated over 3 months. This blood test is taken independent of when you have eaten. It measures the amount of glucose stuck to the hemoglobin (part of your red blood cells), which accumulates over approximately 3 months. This non-fasting blood test determines your average blood sugar level over the previous two to three months. It calculates the amount of blood sugar bound to hemoglobin. Diabetes is diagnosed when your A1C result is 6.5 percent or above on two different tests. Prediabetes is indicated by an A1 resultC between 5.7 and 6.4 percent. A value of less than 5.7 is deemed normal.

4. Oral Glucose Tolerance (OGT) Test

This test involves multiple sampling at various intervals. First sampling is done after overnight fasting to determine fasting blood glucose level. The person ingests sugar syrup or liquid, and the blood samples are collected at 1-hour, 2-hour, and 3-hour intervals. The OGTT is primarily used to diagnose gestational diabetes. The person must fast for 8 hours before doing the OGTT, following which a fasting plasma glucose level is measured and an oral glucose solution is administered.

Following that, blood samples may be obtained up to four times at varied intervals to assess blood glucose levels. OGTTs are often conducted in the morning since glucose levels typically decline during the afternoon. The standard OGTT fasting range for prediabetes is 100–125 mg/dL, 126 mg/dL or more for diabetes, and greater than 92 mg/dL for gestational diabetes. The typical range for OGTT findings after 2 hours is between 140 and 199 mg/dL for pre diabetes, 200 mg/dL or above for diabetes, and greater than 153 mg/dL for gestational diabetes.

Blood Sugar values across categories, for HbA1c, Fasting, Post-Prandial and Glucose Tolerance are as shown in the table below.

Bottom Line

Taking timely precautions is key to prevent type 2 diabetes. Diabetes that comes with age, family history, or genetics cannot be prevented but can be controlled effectively by self-management and expert advice. So having gone through the Who, Why and What of diabetes testing, if you fall under any of the risk factors or notice relative signs or symptoms dont hesitate to consult your healthcare provider immediately and get tested for diabetes.


1. Can I test for Diabetes at home?

A finger prick test using a home testing kit may reveal elevated blood sugar levels but will not diagnose diabetes. Blood tests that assess blood glucose (sugar) levels are the only method to determine whether you or a loved one has diabetes. Only a fully qualified doctor can give a diabetes diagnosis. 

2. How to prevent Diabetes?

If you are someone who’s at risk for developing diabetes, there are certain things you can do to be able to avoid or postpone developing it. The majority of what you need to accomplish involves adopting a healthy lifestyle. Keeping your weight in check, getting regular exercise and getting enough sleep, eating healthy and avoiding smoking and drinking are just some of the things that can be done to ensure prevention. 

3. Can I test for diabetes at home without blood?

Diabetes cannot be diagnosed just by using diabetes home test. People who get unexpected results will need further testing by a doctor. Fasting tests, oral glucose tolerance tests, HbA1c testing, or a combination of these approaches may be performed by the doctor. Another method for testing your blood sugar is the Freestyle Libre system. While this approach has several similar characteristics with a Continuous Glucose Monitor and a meter, it differs in one important way: it does not involve pricking or blood. With the Freestyle Libre, you'll still have a little sensor put under your skin. It differs from a CGM in that it does not provide continuous readings. When you wish to check your blood sugar level, you'll use a reader to scan the sensor rather than pricking your finger like you would with a meter.

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