Diabetes Mellitus Tests to Establish the Diagnosis
Are you experiencing some of these symptoms of the 4Ps: Polyphagia (excessive hunger), Polydipsia (excessive thirst), Polyuria (frequent urination) or Pruritis (itching)? Or you easily get sleepy and tired? Or you have some close relatives, your father or mother, an uncle and so forth with diabetes? Well, you should be aware for having diabetes mellitus. However, to establish a sound diagnosis, you need to visit your physician who may as well send you for a blood test to look into your blood sugar levels…
There are several tests that need to be conducted to diagnose whether you have diabetes or not. Those tests include:
#1 – Fasting plasma glucose test (FPGT). This test will measure your blood sugar or glucose levels. You will be asked to fast for a minimum of 8 hours prior to taking your blood sample. This test is usually arranged so you can do the fasting in the evening and your blood sample to be taken in the morning. The result will show whether you have diabetes or in stage of pre-diabetes.
#2 – Oral glucose tolerance test (OGTT). This test is meant to measure your blood glucose levels in two stages. The first one is similar to the FPGT which is taking your blood sample after a fasting period of a minimum of 8 hours. After your blood take, you will be asked to drink a kind of syrup (sugar diluted in water). The second blood sample will be taken after 2 other hours of your drinking. This test will establish the diagnosis of diabetes or pre-diabetes.
#3 – Random plasma glucose test.Your blood glucose level can also be measured at any time, regardless the time you have been eating your last meal. This test, together with an evaluation of other symptoms, like the above 4Ps, is used to establish the diagnosis of diabetes but not pre-diabetes.
Positive results of those three tests should be confirmed by repeating the fasting plasma glucose test as well as the oral glucose tolerance test on another day.
Fasting Plasma Glucose (FPG) Test
This is the test of choice to diagnose diabetes since it is most convenience and reliable when taken in the morning. Test results can be read as follow:
- A fasting sugar level of 99 milligrams/dL or below means that your glucose level is normal
- A fasting sugar level of 100 – 125 milligrams/dL, concludes that you at a stage of pre-diabetes which is also called by impaired fasting glucose (IFG). It means that you are more likely to get type-2 diabetes in the future, but does not appear yet.
- A sugar level of 126 milligrams/dL and beyond, means that you have diabetes mellitus which however, should then be confirmed by a repeated same test on another day.
Oral Glucose Tolerance Test (OGTT)
Research has concluded that the OGTT seems to be more sensitive compared to the FPGT in diagnosing the stage of pre-diabetes. However, it is less convenient to manage. Test results can be read as follow:
- A blood sugar level after 2 hours of 139 milligrams/dL or below means that your glucose level is normal
- A blood sugar level between 140 – 199 milligrams/dL 2 hours after drinking the syrup, concludes that you are in a stage of pre-diabetes called impaired glucose tolerance or IGT, which means that you are more likely to develop type-2 diabetes in the future, but it does not appear yet.
- A 2-hour blood sugar level of higher than 200 milligrams/dL, means that you have diabetes mellitus which however, should then be confirmed by a repeated same test on another day.
To establish the diagnosis of Gestational diabetes, plasma glucose levels measured during the OGTT can be observed. But in this case, blood sugar levels will be checked 4 times during a test with an interval of one hour between two blood takes. If your blood sugar levels are above normal twice at the minimum during the test, you may be considered to have gestational diabetes.
The following scheme is showing the above-normal results for the OGTT for gestational diabetes cases:
- Fasting – 95 milligrams/dL or beyond
- After 1 hour – 180 milligrams/dL or beyond
- After 2 hours – 155 milligrams/dL or beyond
- After 3 hours – 140 millgrams/dL or beyond
Note: Some laboratories might use other standards for this test.
Random Plasma Glucose Test
A random plasma glucose level of 200 milligrams/dL or beyond, added by the following symptoms, can be concluded that you have diabetes:
- Polyuria or frequent urination
- Polydypsia or excessive thirst
- Polyphagia or excessive hunger
- Pruriitis or itching
- Unexplained weight loss
- Or other symptoms such as fatigue, blurred vision, and un-healing sores.
Based on those findings, your physician will examine your blood sugar level on another day using the FPGT or the OGTT to establish the diagnosis.