Blood sugar tests
What are blood sugar tests?
This test is used to measure the level of glucose in the blood. Glucose is the main form of energy that the body needs to function and it is maintained within a narrow range by the body. Unfortunately elevated glucose level of diabetes is a silent disease that can cause extensive damage if left untreated. Timely testing helps to catch the disease early and to keep it well-controlled.
Why blood sugar test is conducted?
This is an important investigation as both high and low blood glucose levels have serious repercussions for health and normal functioning.
- It is carried out to confirm the existence of diabetes.
- Another important reason is to check whether diabetes is being properly managed.
- People at high risk may have this test from time to time to check for pre-diabetes.
- To check for drop in blood sugar levels, as a dramatic drop can be life threatening.
Who should go for blood sugar test?
These tests are generally advised in the following situations:
- Women who are pregnant are advised to have this test to check for gestational diabetes, or diabetes that develops only during pregnancy.
- People above the age of 40 who are at a risk for developing diabetes.
- Those persons whose one or both parents suffer from diabetes.
- Persons who experience an increase in urination and thirst along with sudden weight loss for no apparent reason.
- People with delayed recovery from wounds, boils or sores on legs.
Procedure for blood sugar test
There are several methods to conduct blood sugar tests.
- Fasting blood sugar (FBS): This test is carried out first thing in the morning before eating anything as it should be done after an 8 hour fast. Normally, this test is used to diagnose diabetes.
- Postprandial glucose test (PC): This test is conducted 2 hours after having a meal. A slight increase in blood sugar after a meal is normal which should have come within normal levels after 2 hours.
- Glucose tolerance test or continuous testing: This is a diagnostic test and is conducted after consuming glucose. You will have the first test after fasting for 8 hours which will be followed by a number of tests after every 30 minutes. This test lasts for about 2 hours. Some labs only take the baseline and one sample after 2 hours.
- Random glucose test: This is conducted at any time of the day. For a person who does not suffer from diabetes, it should be within the normal range.
- Glycohemoglobin A1c/ HbA1c: This measures the amount of glucose that has binded with red blood cells and can help to know whether your diabetes has been managed properly or not over the last couple of months. The result of this test gives a long term picture and is used to guide further treatment.
- Home Testing: People with known diabetes are advised to test for blood sugar levels at home with a glucometer for better management.
Interpretation of results
Diabetes is best managed with a combination of diet, exercise and medication. Thus regular testing forms the basis of the treatment to be followed, as frequent fluctuations in blood sugar levels causes long term damage to various organs within the body.
The normal ranges are as follows:
- Fasting blood sugar: 70 - 100 milligrams per deciliter (mg/dL). If it is between 100- 125 mg/dL then it indicates a stage of prediabetes.
- Postprandial glucose test: should be less than 180 mg/dL. An elevated blood sugar level indicates the presence of diabetes.
- Glucose tolerance test or continuous testing: 110 mg/dL for the baseline test. Less than 140 mg/dL after the 2 hour test.
- Random glucose test: levels below 125 mg/dL.
- Glycohemoglobin A1c: less than 5.7 % is considered to be normal.
Written by: Nandita tripati
Date last updated: January 09, 2015