Blood test is useful to diagnose pre diabetes, diabetes type 1, diabetes type 2 and gestational diabetes. Diabetes test is easier, faster, and less expensive to perform.
Normally used diabetes testing
Diabetic testing is testing for glucose or sugar level in blood or plasma, commonly used tests are fasting plasma glucose test, oral glucose tolerance test, and random plasma glucose test.
Fasting plasma glucose (FPG) test - this test is to measure blood’s plasma-glucose after fasting for at least 8 hours, thus the name fasting plasma glucose test. This test is useful to detect all types of diabetes.
Oral glucose tolerance test (OGTT) - which measures blood glucose after 8 hours of fasting and 2 hours after the person drinks a glucose-containing beverage. This test is effective to diagnose all types of diabetes.
Random plasma glucose test - also called a casual plasma glucose test, because there is no fasting required or worry about what we have eaten. This test, along with an assessment of symptoms, is used to diagnose diabetes but not pre-diabetes. However, once random plasma glucose test confirms diabetes needs to be reconfirming by FPG or OGTT.
If the test result indicates that a person has diabetes, then should be re-confirming with a second test on a different day.
The fasting plasma glucose (FPG) test or fasting blood sugar test, which measure blood sugar or glucose levels and is useful in diabetes diagnosis. It is a simple, relatively reliable, and inexpensive test for diabetes diagnosis.
What is fasting blood sugar test?
Fasting triggers a glucagon hormone, when there is no longer enough glucose in blood for energy. The pancreas produces glucagon hormone, and it instructs the liver to convert stored glycogen to glucose and release it into the bloodstream for energy requirements.
Once liver releases glucose into the bloodstream, normal body immediately releases insulin to prevent hyperglycemia (high blood glucose). However, for diabetics, there is no longer enough insulin secretion or improper use of available insulin, thus fasting blood-glucose level stays high.
For FPG test, you require to have been fasting for at least 12 to 14 hours (must not to eat or drink anything except water for 12 to 14 hours). Because of this prolong fasting; the test is convenient to have in the morning.
Blood glucose levels: FPG test can be mention with different measurement units; they are:
milligrams per deciliter (mg/dl), is the unit to measure that shows ‘x’ milligrams of glucose in the blood plasma per deciliter of blood, Blood glucose level in mg/dl is the unit used in United States.
millimoles per liter (mmol/L), is the unit of measure that shows 'x' mmol concentration of glucose in the blood plasma per liter of blood. In most part of the world (except United States) uses this unit for blood-glucose test results.
Normal blood-glucose levels
Blood glucose level of 0 mg/dl to 99 mg/dl is considered as normal range.
Blood glucose level of 3.89 to 5.5 mmol/L is considered as normal range
Pre-diabetes blood-glucose levels
Blood glucose level of 100 mg/dl to126 mg/dl suggests pre diabetes
Blood glucose level of 5.56 to 7 mmol/L suggests pre diabetes
Pre-diabetes is called by impaired fasting glucose, indicating an increased risk of developing type 2 diabetes.
Blood glucose level of higher than 126 mg/dl confirmed as diabetes.
Blood glucose level of higher than 7 mmol/L confirmed as diabetes.
Hypoglycemia blood glucose levels
Blood glucose levels lower than 70 mg/dl is considered as hypoglycemia.
Blood glucose levels lower than 3.89 mmol/L is considered as hypoglycemia.
Even if the results are within the normal range, additional testing may be ordered to determine if a person has additional risk factors for diabetes, such as high body mass index (BMI), or if exhibits other symptoms of diabetes.
Also if the test result confirms diabetes at the border line level, then doctor may order another test on another day to reconfirm diabetes.
The oral glucose tolerance test measures the body’s ability in glucose metabolism and clearing excess glucose in a bloodstream.
Oral glucose tolerance test
The oral glucose tolerance test (OGTT), can also be called as glucose tolerance test or sugar tolerance test. It is used to measures the body’s ability in glucose metabolism and clearing excess glucose in the bloodstream. The test is useful in the diagnosis of diabetes, gestational diabetes and pre diabetes.
Importance of the OGTT
OGTT is better able to diagnose high blood-glucose after a glucose challenge than the fasting blood-glucose test. Doctor may recommend OGTT, if he/she suspects diabetes in cases where patients fasting, blood-glucose level is normal, but have other symptoms of diabetes or overweight.
An OGTT is most commonly preferred to check for diabetes that happens during pregnancy (gestational diabetes).
Oral glucose-tolerance test procedure
OGTT test needs at least 8 to 12 hours of fasting. In addition, another test after the patient drink a glucose-rich beverage, typically a drink containing 75 grams of carbohydrates (other different levels of glucose consumption are also possible, but the result may be analyzed accordingly). Blood will be drawn and tested after one hour and two hours after having a glucose beverage.
What is the Oral glucose tolerance?
Oral glucose tolerance means the body ability to tolerance against the consumption of a certain amount of glucose. That is how effective the body is in breaks down (metabolizes) blood glucose.
OGTT provides details about how quickly glucose is absorbed into the bloodstream for use by body cells as energy. The rate of glucose clearance depends on the amount of glucose consumed. After fasting, the normal blood-glucose rate is 60 to 100 mg/dl.
Normal, pre-diabetes, diabetes OGTT blood glucose level
For 75 grams of glucose consumption; the normal, pre-diabetes, diabetes blood-glucose levels are as below.
Normal: 139 mg/dl or 7.72 mmol/l and below
Pre-diabetes: 140 to 199 mg/dl or 7.77 to 11 mmol/l
Diabetes: 200 mg/dl or 11.1 mmol/l and above
Oral glucose tolerance test is useful to diagnose diabetes, as well as provides additional information about the body’s ability to metabolize blood glucose. Higher OGTT values are likely to reflect diet, lifestyle problems and problems of insulin functioning.