How Can Prediabetes and Diabetes Be Identified?
Diabetes can be diagnosed using the following tests:
After you have not eaten for at least eight hours, your blood glucose is measured
using a fasting plasma glucose test. This test is used to identify diabetes or
prediabetes.
An oral glucose tolerance test checks your blood sugar levels two hours after
consuming a glucose-containing beverage and after you have gone at least eight
hours without eating. This test can be used to diagnose diabetes or prediabetes.
Your doctor analyses your blood sugar in a random plasma glucose test,
regardless of when you last had food. This test is used to diagnose diabetes, not
prediabetes, in conjunction with a symptom assessment.
It is possible to detect or confirm prediabetes or diabetes with a haemoglobin A1c
(HbA1c) test without fasting.
In the event that a test result indicates that you have diabetes or prediabetes, your doctor will
repeat the oral glucose tolerance test or the fasting plasma glucose test on a different day to
confirm the results.
A further test that can assist identify type 1 diabetes and rule out other forms is the zinc
transporter 8 autoantibody test.
FPG (Fasting Plasma Glucose) Test
The best time to take this test is in the morning. Table 1 presents the findings and their
interpretation. If your fasting glucose level is between 100 and 125 mg/dL, you have impaired
fasting glucose (IFG), a type of prediabetes that increases your risk of developing type 2 diabetes
but does not yet have it. If you repeat the test on a different day and your result is 126 mg/dL or
higher, you have diabetes.
Oral Glucose Tolerance Test (OGTT)
Although the OGTT is less easy to administer, studies have shown that it is more sensitive than
the FPG test for identifying prediabetes. You must fast for at least eight hours prior to the OGTT.
Before and two hours after consuming a beverage that contains 75 grammes of glucose dissolved
in water, your plasma glucose level is tested. Table 2 displays the results and their implications.
You have impaired glucose tolerance, or IGT, a type of prediabetes in which you are at risk of
developing type 2 diabetes but do not yet have it, if your blood sugar level is between 140 and
199 mg/dL two hours after consuming the liquid. You have diabetes if your 2-hour glucose level
is 200 mg/dL or higher, as determined by repeating the test on a different day.
The OGTT is also used to diagnose gestational diabetes. Throughout the test, blood sugar levels
are measured four times. You have gestational diabetes if your blood sugar levels are higher than
usual at least twice during the test.
The glucose challenge test
This test is a condensed form of the OGTT and is also known as the 1-hour glucose tolerance
test. Compared to other tests, this shorter one is more accurate in predicting type 2 diabetes.
You are diagnosed with intermediate hyperglycemia if, one hour after consuming 75 grams of
glucose dissolved in water, your blood glucose level is at or above 155 mg/dL. You have type 2
diabetes if your blood glucose levels are 209 mg/dL or above.
Random Plasma Glucose Test
If you have diabetes and have a random blood glucose level of 200 mg/dL or above, you may
also have the following symptoms:
An increase in urination
Unaccounted-for weight loss
Increased thirst
Fatigue, impaired eyesight, increased appetite, and non-healing wounds are other symptoms. To
confirm the diagnosis of diabetes, your doctor will use the FPG or the OGTT to measure your
blood glucose level on a different day.
Haemoglobin A1c Test (HbA1c)
This test determines the proportion of glucose-coated haemoglobin, the oxygen-carrying protein
in your blood. In order to do this test, your doctor will take a blood sample from your arm using
a needle. For analysis, the blood sample is sent to a laboratory. Your doctor can see a snapshot of
your blood glucose control over a number of months with your HbA1c reading.
A HbA1c between 5.7% and 6.4% indicates prediabetes, which can be rectified with lifestyle
modifications. Diabetes is defined as having a HbA1c of 6.5% or above.
Type 2 diabetes is the only one that can be diagnosed by HbA1c testing; type 1 or gestational
diabetes cannot.
Criteria for Diagnosing Diabetes
Your doctor uses these values as a guide while gathering information to confirm a diabetes
diagnosis:
The criteria for diagnosing prediabetes
Test Results
HbA1c 5.7-6.4%
Fasting blood glucose 100-125 mg/dL
2-hour OGTT blood glucose 140-199 mg/dL
Diagnostic Standards for Diabetes
Test Results
HbA1c 6.5% or higher
Fasting blood glucose 126 mg/dL or higher
2-hour OGTT blood glucose 200 mg/dL or higher
Type 1 Diabetes Diagnosis
In order to determine whether you have type 1 diabetes, your doctor might wish to do additional
tests after confirming a diabetes diagnosis. Children and those without additional diabetes risk
factors who are diagnosed with the disease should pay particular attention to this.
Autoantibody test. A zinc transporter 8 autoantibody (ZnT8Ab) test might be recommended by
your physician. Obtaining a quick and precise diagnosis that can result in fast treatment is the
aim of this blood test.
Insulin in blood test: C-peptide test. This test aids in determining the amount of insulin
produced by your pancreas. Insulin and C-peptide are released into your bloodstream
simultaneously by your pancreas in equal proportions. Although C-peptide remains in your blood
longer than insulin, it has no effect on blood glucose levels. For this test, your physician will
draw a tiny amount of blood and send it to a laboratory.
Ketones. To check for ketones, your doctor can use a paper test strip to test your pee. Your body
produces ketones, which are acids, when it uses fat as fuel rather than glucose. Type 1 diabetes
may be indicated by this.
Highlights
A number of assays, such as the haemoglobin A1c test, random plasma glucose test, oral glucose
tolerance test, and fasting plasma glucose test, can be used to confirm a diagnosis of diabetes.
Your doctor can use these tests to determine whether you have diabetes or are at risk of getting it
(prediabetes).
FAQs about Diagnosing Diabetes
How diabetes is diagnosed?
Blood tests can be used by your doctor to identify diabetes. To be certain of the diagnosis, they
might wish to do many types. Your doctor may perform further blood tests to check for
autoantibodies or check your urine for ketones if they believe you may have type 1 diabetes.
How do I accept a diabetes diagnosis?
You may experience a range of emotions after finding out you have diabetes. Recognize that
more than 38 million Americans suffer from diabetes. Numerous organizations and support
groups are available to aid with diet control, emotional well-being, and lifestyle advice to help
you live a healthy life with diabetes.