Blood Tests in Diabetes – Methods & Results

Blood Tests in Diabetes – Methods & Results

Is there an easy way to know whether you are Diabetic? Most of us are aware of the fact that Diabetes can be detected by simple blood tests. But, which tests to do? Which test is the most accurate and affordable one? Is Fasting Blood Glucose (FBG) always a mandatory test? What are the ideal conditions to be satisfied before performing these tests? These are some of the usual questions that we Doctors face at the hospital. If you think you are Diabetic or want to make sure that you are not a Diabetes patient, you should know the basics about the blood tests or exams. This is very important because Diabetes is usually an asymptomatic disease to start with and blood tests are the only way to detect Diabetes at an early stage. If you want to know the various blood test options for detecting Diabetes and want to do it the proper way, you have reached the right page. I hope you are already aware of the term Diabetes. No doubt, you must have heard about it already. Read this article to Learn the basics of Diabetes.

Fasting Blood Glucose (FBG)

One of the most widely used blood test to diagnose Diabetes, the only problem with this test is that it requires 8 to 12 hours of fasting. Blood is usually drawn in the morning before having breakfast. The person may drink water before the test. No other liquids or food should be taken before the scheduled time of blood test.

70 to 99 mg/dl or 3.9 to 5.5 mmol/l : Normal fasting glucose level
100 to 125 mg/dl or 5.6 to 6.9 mmol/l : Pre-Diabetes
Higher than 126 mg/dl or > 7.0 mmol/l : Diabetes

Pros : Cheap and affordable compared to the A1c test, only one sample required, accurate
Cons : Fasting should be proper

NOTE : This test can also be done with a glucometer which you can be easily carried in your pocket.

Must Read : Tips to Consider before Buying Glucose Meters &

                        Top 5 Glucose Meters in India

A1c Test (HbA1C)

This test measures the average amount of glucose in blood over the last 3 months. Also called as the Glycated Haemoglobin (Glycohaemoglobin) or Haemoglobin A1c (Hb A1c) test. Glucose in blood is bound to a certain fraction of Haemoglobin (the oxygen carrying protein in red blood cell) which is proportional to the concentration of glucose in blood. Using this principle, we can find the amount of glucose bound to the red blood cells. The average life of red blood cells is 3 months and thus we can find the glucose concentration of the individual for the last 3 months by employing this method.

Less than 5.7% (39 mmol/mol) : Normal
5.7% to 6.4% (39-46 mmol/mol) : Pre-diabetes
6.5% (47 mmol/mol) or higher : Diabetes

Pros : Repeated blood samples are not required for 3 months, it is a once in 3 month test or a half yearly test. No fasting is required as blood sample can be taken at any time of the day.
Cons : The test is a bit costly compared to the other blood tests. This test cannot be used in certain cases like pregnancy, after blood transfusions, known kidney or liver disease patients and in patients with bleeding disorders. Another important thing to note is to do this test from Standardised Laboratories only, otherwise the result cannot be used for diagnosis of Diabetes.

2 Hour Oral Glucose Tolerance Test (OGTT)

The patient is advised to drink a 75 gram glucose solution. Blood samples are taken after 2 hours of drinking the glucose solution and they are examined.

Less than 140 mg/dL (7.8 mmol/L) : Normal glucose tolerance level
From 140 to 199 mg/dL (7.8 to 11.1 mmol/L) : Impaired glucose tolerance
200 mg/dL (11.1 mmol/L) or higher on more than one occasion : Diabetes

Pros : No fasting required. Affordable test. This test is preferred in pregnant women
Cons : Patient has to wait 2 hours after drinking the solution to give the blood sample.

NOTE: You can do this blood test at your home! That’s another good reason why you should own a [easyazon_link keywords=”Glucose meter” locale=”IN” tag=”btdwords-21″]Glucometer[/easyazon_link] in case you’re diabetic. To read the reviews of some of the popular glucose meters, click here.

When are these Tests indicated?

The tests for Diabetes can be done in the following situations :-

  • When a person has the symptoms and signs of Diabetes
  • For regular blood sugar monitoring in an already diabetic patient. The other good tests which should be considered in this group includes the Kidney Function Tests, Lipid Profile Tests etc.
  • As screening tests to detect Diabetes in apparently normal individuals
  • To screen pregnant women for Gestational Diabetes Mellitus (diabetes detected first time in pregnancy)
  • At the Emergency Department

Don’t think twice before doing these simple tests. It just takes a drop of your blood for the diagnosis and when the test result comes negative, the peace of mind is worth more than anything. I hope you liked this article and don’t forget to share it with your friends.



Image Credit – Oskar Annermarken

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