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August 24, 2022 | Blood Tests

What Are The Blood Tests for Diabetes?

Woman doing finger prick for diabetes at home

When diabetes is mentioned, your brain probably quickly leaps to thinking about sugar and testing. You may think of a finger prick or the latest patches you may see on someone’s arm for diabetes testing, but do you know about the tests involved in diagnosing diabetes and diabetes management?

Diabetes overview

Diabetes is a chronic health condition that affects how your body turns food into energy1.  The three main types of diabetes include type 1 diabetes, type 2 diabetes, and gestational diabetes (which develops in some pregnant women). In addition to these three types of diabetes, there is also prediabetes. Prediabetes means that blood sugar levels are higher than normal but not high enough for a type 2 diabetes diagnosis. More than 96 million adults in the US have prediabetes, but roughly 8 in 10 of them don’t know they have it1.

How is diabetes diagnosed?

Diabetes is diagnosed using one or more of the following blood tests: A1C, fasting plasma glucose (FPG), and oral glucose tolerance test (OGTT)2.


The A1C test measures your average blood glucose for the past two to three months. The advantages of the A1C test are that you don’t have to fast or drink any special solutions before the blood draw.

Normal test results have an A1C of less than 5.7%, A1C test results ranging from 5.7% to 6.4% indicate prediabetes, and anything 6.5% or higher equals a diabetes diagnosis.

Fasting plasma glucose (FPG)

The FPG test checks your blood glucose levels after fasting. This test is typically done first thing in the morning, as you are required not to eat or drink anything (besides water) for at least eight hours before the test.

For the FPG test, normal results are less than 100mg/dL, test results ranging from 100mg/dL to 125mg/dL indicate prediabetes and diabetes is diagnosed when results are 126 mg/dL or higher.

Oral glucose tolerance test (OGTT)

The OGTT involves drinking a special sweet drink. This is a two-hour test that measures your blood glucose levels before consuming the special drink and two hours after you drink the beverage. The test shows your healthcare provider how your body processes sugar.

For the OGTT, normal test results are less than 140mg/dL, test results ranging from 140mg/dL to 199mg/DL indicate prediabetes, and diabetes is diagnosed when test results are 200mg/dL or higher.

Testing for gestational diabetes

Gestational diabetes is a type of diabetes that can develop during pregnancy in women who don’t already have diabetes. Gestational diabetes affects 2% to 10% of pregnancies every year3. Sometime between weeks 24 and 28 of pregnancy, women complete a test similar to the OGTT. The one hour glucose tolerance test requires women to drink a sugar mixture, wait an hour, and then get their blood drawn. This prenatal blood test is also commonly called a glucose screening test or the one-hour glucose challenge.

Diabetes management

Because diabetes is a chronic disease, there are steps that diabetics have to take to manage blood sugar levels. Depending on the type of diabetes a diabetic has, daily checks measuring blood sugar levels will vary4. The Centers for Disease Control and Prevention (CDC) says that the typical times to check blood sugar are first thing in the morning (before eating or drinking anything), before a meal, two hours after a meal, and at bedtime.

There are also the ABCs for diabetes that diabetics tend to follow for diabetes management4:

  • A: Get a regular A1C test
  • B: Try to keep blood pressure below 140/90mm Hg (or the target your healthcare provider sets)
  • C: Manage cholesterol levels
  • S: Stop smoking or don’t start

Managing diabetes can be time-consuming, especially when some diabetics need to get A1C tests done quarterly. Scarlet® makes it easy to stay on top of diabetes management because we come to you for blood draws.

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