Diabetes blood tests and what they mean
Doctors can diagnose diabetes through different blood tests including the A1C test, the fasting blood sugar test, an oral glucose tolerance test, and a random blood sugar test. If you’ve ever wondered what these different tests measure and what the results mean, then read on. First, here is more information about the different types of diabetes.
Types of diabetes
Type 1 Diabetes — this type of diabetes is caused by an autoimmune reaction in which the body attacks its own cells. This prevents the body from making insulin. Type 1 Diabetes is usually diagnosed in children, teenagers or young adults and requires them to take insulin daily, but there is no permanent cure.
Type 2 Diabetes — this type of diabetes develops gradually and is usually diagnosed in adults. For people with Type 2 diabetes, their cells do not respond well to insulin, even though the pancreas will try to produce more insulin to compensate. This means that the body cannot maintain normal blood sugar levels.
Gestational diabetes — this occurs in pregnant women who may have never had diabetes before. Risk factors for gestational diabetes include: being obese at the start of pregnancy, having had gestational diabetes in a past pregnancy, or having a family member with diabetes.
Prediabetes is a health condition that can develop into Type 2 diabetes. People with prediabetes have higher than normal blood sugar levels, but not high enough to be considered Type 2 diabetes.
Blood tests used to diagnose diabetes and what they mean
Doctors will use one or more blood tests to diagnose diabetes, and they may even repeat some tests as sometimes results can fluctuate. Here are the different types of tests used to diagnose diabetes.
A1C test
This blood test measures blood sugar levels for the last two to three months by measuring the percentage of blood sugar attached to hemoglobin in our blood. Hemoglobin is the protein in red blood cells that carries oxygen. When glucose travels in our blood, it attaches to hemoglobin and can be measured via the A1C test.
More glucose in blood means that there will be more glucose bonded to hemoglobin. Here is what the results mean for an A1C blood test:
Normal: below 5.7%
Prediabetes: 5.7 to 6.4%
Diabetes: 6.5% or higher
Fasting blood sugar test
This test measures blood sugar levels after an overnight fast or not eating 8 to 10 hours before the test. Eating or drinking before a fasting blood sugar test can result in inaccurate results. Here is what the results mean:
Normal: 99mg/dL or lower
Prediabetes: 100 to 125 mg/dL
Diabetes: 126 mg/dL or higher
Oral glucose tolerance test
This is another test that requires an overnight fast. A doctor will measure your fasting blood sugar levels, then have you drink a sugary liquid. Then the doctor will draw blood again to measure blood sugar levels a couple hours after the drink. Blood sugar is measured periodically over the next 2 or 3 hours. Here is what results mean after about 2 hours:
Normal: 140 mg/dL or lower
Prediabetes: 140 to 199 mg/dL
Diabetes: 200 mg/dL or higher
Random blood sugar test
This blood test can be done at any time — you don’t have to fast. However, a random blood test can only detect diabetes, not prediabetes. A level of 200 mg/dL or higher indicates diabetes.
Tests for Type 1 diabetes
There are some tests that can be used to diagnose Type 1 diabetes, but not Type 2. First, your blood might be tested for autoantibodies. Antibodies are proteins in blood that protect cells from foreign substances. Autoantibodies are antibodies that target the body’s own cells. Because Type 1 diabetes is caused by an autoimmune reaction, the presence of autoantibodies can indicate Type 1 diabetes.
Doctors may also test urine for ketones, which are substances produced when the body uses muscle and fat tissues for energy which occurs in people with Type 1 diabetes.
Testing for gestational diabetes
The test results above may not apply to gestational diabetes, which is usually diagnosed using blood tests 24 to 28 weeks into pregnancy. However, doctors may test for gestational diabetes earlier in pregnancy if a woman has risk factors for gestational diabetes.
In addition, remember that blood sugar levels fluctuate throughout the day, and other conditions can impact blood test results. For example, stress, iron-deficiency anemia, kidney failure, and liver disease can influence A1C test readings, which is why it’s important to do more than one test and do follow-up tests to diagnose diabetes.
Who should get tested for diabetes?
Anyone with symptoms or risk factors should get tested for diabetes. According to the National Institutes of Health (NIH), this includes: people age 45 or older; people 19 to 44 years old who are overweight, obese, or have other risk factors; and women who had gestational diabetes. You can also check out the NIH website to learn the risk factors of Type 2 diabetes.
If you’re interested in doing an online consultation and receiving treatment from our team of licensed medical providers, check out Alpha’s website. We’re here to support you by making health care convenient, accessible, and affordable for all.
