Diabetes Diagnosis, Which Blood Tests to be done?

August 10, 2021September 12, 2022 Helal Medical

Diabetes is a disease where blood sugar (glucose) levels are higher than normal ranges. Many test are available for Diabetes Diagnosis, and monitoring diabetic patients. In this article, I discuss the most popular tests used to diagnose diabetes. Here , I discuss some important points related to Blood Tests used for Diabetes Diagnosis, including:

The 4 basic Blood Tests for Diabetes Diagnosis
What test to start with for for Diabetes Diagnosis
About Diabetes types.

There are 4 basic Blood Tests for Diabetes Diagnosis:

Random plasma (blood) glucose
Fasting blood glucose (FBG) , also called Fasting Blood Sugar (FBS).
Oral glucose tolerance test (OGTT)
Hemoglobin A1c (A1c) test.

What test to start with for for Diabetes Diagnosis

If you experience symptoms suggesting diabetes or you may have family history and you want to check-up. So, what Blood test to start with? Basically, the test you choose depends on you condition, whether you have symptoms or no symptoms, as following:

You have no symptoms , but you want to do the test for check-up or as one of the requirements for any purpose. Therefore, start doing Random blood glucose test. Random means you go for the test any time during that day. It does nor require Fasting like FBS test. The result must not exceed 140 to 180 mg/ml.
On the other side, you have symptoms suggestive of diabetes. Then FBS and PPBS blood tests are recommended. FBS test requires fasting for 8 to 10 hours. PPBS test is done 2 hours after taking your regular meal.

Diabetes in a glance

Type 1 Diabetes
It is not a common type of Diabetes, where the body does not produce insulin. It occurs usually in children and young adults.

Type 2 Diabetes
The body does not produce enough insulin or can not use insulin. It is the most common type, about 90% of diabetes are Type 2.

Gestational diabetes
It occurs with pregnancy, usually with no symptoms,

Diabetes Diagnosis, Which Blood Tests to be done?

Laboratory Tests used for Diabetes Diagnosis

Before starting to discuss the tests used for diabetes , you need to know whether you are in need to do those tests.

You should be tested if you experience any symptoms of diabetes.
if you dnt have symptoms, but have some risk factors , like family history.
Also it is recommended to make it part for any routine check-up, specially if you are 45 years or older, or overweight.
You are already diabetic, so you need to do the tests to monitor and manage the illness.
Also it is done routinely for during pregnancy.

Fasting and PPBS Tests

Fasting and Post-Prandial Blood Sugar , are the most commonly used tests for Diabetes Diagnosis. 2 blood samples are collected. The first sample is collected while the patient is fasting (for 8-10 hours) to do the FBS test. Then the patient is instructed to eat his regular meal. Then, we collect the second blood sample to do the PPBS test 2 hours after meal.

Fasting blood sugar test (FBS), is done usually at morning after being fasting for 8-10 hours. Normal levels: 80 mg/dl to 120 mg/dl.

Post Prandial Sugar Level Level
Nondiabetic – Normal
Prediabetic state – Normal, no symptoms
Diabetic State

Level
Below 140 mg/dL (7.8 mmol/L)
140-180 mg/dL (7.8- 10.0 mmol/L)
Above 180 mg/dL (10.0 mmol/L)

When do you need to do Fasting and PPBS Tests ?
It may be requested for routine check-up. Also, it is recommended if you have one or more of the following symptoms:
– You get tired after little effort.
– Sudden weight loss without known reason.
– Delayed healing of your wounds.
– Frequent urination.
– Feelin of thirst.
– Vision problems.
– You experience tingling sensation in hands or feet.

Oral glucose tolerance test (OGTT)

It is a blood test done to examine how your body will deal with ingested glucose. Patient must be fasting for 8-10 hours. It is done using a blood sample. The test takes about 3-4 hours. It is used to diagnose Type 2 diabetes and Gestational diabetes.

Interpretation of result of (OGTT)

*Fasting blood Glucose Levels:
– 100 mg/dl or below is considered normal.
– Results between 100 and 125 mg/dl (of FBG) is considered prediabetes.
– Result more than 126 mg/dl is diabetes.
*After one hour, 180 mg/dl or more is diabetic.
*After two hours, 140 to 180 mg/dl is a prediabetic state. While more than 180 mg/dl indicates the presence of diabetes.

Hemoglobin A1c (HbA1c) test

HbA1c test measures the average amount of blood glucose attached to hemoglobin during the past three months. Three-month is the life span of red blood cell. So, It is a measure of blood glucose over the past 12 weeks. While other tests (FBG and PPBG) measure the glucose level at the moment of testing.