What are examples of tests for diabetes and how is it diagnosed?
- Diabetes is diagnosed with blood tests
- The simplest is called a fasting blood sugar or FBS
- Two FBS tests are taken during two different occasions to make the diagnosis of type 2 diabetes
- The oral glucose tolerance test or OGTT is also a blood test
- It takes a little more time (two hours), but only one test is usually required to confirm a diagnosis
- A1C blood tests are taken to track the changes on blood sugar over the previous 3 months
- The A1C is less effective in some racial groups than in Non-Hispanic Whites
- For example, the A1C is less reliable among Phillipino and several Asian racial groups
- For the American Indian or Alaska Native who has mixed blood parentage, the A1C also may be less reliable in you
What is a fasting blood sugar (FBS) test?
- This means that a sample of the blood is drawn usually in the morning–after not eating or drinking (except water) for 8-12 hours.
- The concentration of glucose or sugar in the blood is examined
- FBS results:
- Normal =less than 99 mg/dl
- Pre diabetes=100-125 mg/dl
- Diabetes=126 mg/dl or higher
- Two FBS tests taken over two different time periods are required to confirm a diagnosis of Type 2 diabetes
What is mg/dl?
- mg/dl means "milligram per deciliter"
- It is used to measure blood sugar (glucose) concentration
- This measurement may also be written as mg%.
What is oral glucose tolerance test (OGTT)?
- An OGTT is usually a 2-hour oral glucose tolerance test
- The person has a fasting blood sugar (FBS) test
- Then they are then given a concentrated sugar drink
- Exactly 2 hours after the sugar drink, another blood test sample is drawn to check the level / concentration of sugar (glucose) present in the blood
- This test is only needed once but requires that you remain close to the clinic for two hours
- OGTT measures fasting blood sugar before and after a person drinks a solution containing concentrated glucose (sugar),.
- OGTT results mean pre-diabetes if:
- FBS is 100-126 mg/dl or less.
- And the second test is 140-199 mg/dl two hours after the glucose drink.
- OGTT results mean diabetes is 200+ mg/dl after 2 hours
What is an A1C test (also called hemoglobin A1C (HbA1C), glycated hemoglobin, or glycohemoglobin test)?
- Hemoglobin is in the red blood cells (carries oxygen to every cell in the body)
- Sugar in the blood attaches to hemoglobin and creates hemoglobin A1C
- The more sugar in the blood, the higher percentage of cells with hemoglobin A1C
- Red blood cells live for about 3 months
- The sugar you have eaten over the past three months is attached to those cells
- So, an A1C test is a blood test that reflects your average blood glucose levels over the past 3 months