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What is a diabetes test? A simple answer.

Have you got a diabetes test booked and don’t know what to expect? Don’t worry, we’re about to answer: what is a diabetes test?

what is a diabetes test?

What is a diabetes test?

First off, there are a couple of ways to test whether you may have diabetes or prediabetes (which means you’re at risk of developing Type 2 diabetes). Some of these tests are also used by people with diabetes to track how well they’re managing their blood sugar levels over time. 

Often, you may need to have a test repeated, or to have more than one type of test for your doctor to be sure that you have diabetes. So don’t worry if this happens to you. There are a number of things that can affect your blood sugar levels, so it’s better to double check than to make any decisions from one result.

Here, we’ll go through the main types of diabetes tests, what you should expect, and what they can tell you about your blood sugar. These tests can tell you what kind of diabetes you have: Type 1, Type 2, or gestational diabetes, or even prediabetes.

If you want to test if you’re at risk of Type 2 diabetes, watch this 1 minute video.

1.     Fingerstick test

This is a simple and quick test that you may have already had as part of a general check-up at your doctor or clinic. Your finger is pricked and a small sample of blood is tested by a machine (called a glucometer) to measure your blood sugar levels at that moment. 

Did you know? In South Africa, blood sugar levels are measured in mmol/l, and for a random finger prick test a result of more than 10 mmol/l suggests you may have diabetes. Typical blood sugar levels are between 4 and 7 mmol/l. If your result falls between 7 and 10 mmol/l you could have prediabetes.

If your doctor suggests you don’t eat for eight hours before the finger prick test, this is called a fasted fingerstick test, and a result of 7 mmol/l or more suggests you may have Type 2 diabetes.

Fingerstick tests are also used by people with diabetes to monitor their blood sugar levels throughout the day. Here’s the goal for normal blood sugar if you have diabetes.

2.     Oral glucose test

The oral glucose test is an early warning test for Type 2 diabetes and gestational diabetes. This test takes a bit longer than the fingerstick test and you would usually have it first thing in the morning, after not eating for eight hours.

First, the nurse takes a blood sample and uses this as the baseline, or starting point, for your blood sugar levels. Next, you drink a sugary solution and then have more blood samples taken to measure the level of sugar in your blood over a few hours. This shows how the insulin in your body handles sugar: does it process it as expected, or does it struggle to deal with the sugar you’ve just drunk?

If there is some insulin resistance,  high levels of sugar stay in your blood. (Here’s a simple explanation of insulin resistance). If there are higher than expected levels of sugar in your blood after a certain time, this could show possible diabetes.

The results you get are similar to the fingerstick test. When testing for Type 2 diabetes, after two hours normal blood glucose levels are 7.8 mmol/l. Results between 7.8 and 11 mmol/l could indicate pre-diabetes, and 11.1 mmol/l and higher could mean you have diabetes.

Mayo Clinic

For gestational diabetes, levels higher than 7.8 mmol/l after one hour means you should take a three-hour test. But if after one hour your blood sugar levels are more than 10.6 mmol/l it is likely you have gestational diabetes. Here’s all you need to know about gestational diabetes.

The oral glucose tolerance test is also something you may have to repeat at another time, to take into account other factors that could affect your blood sugar readings on the day.

3.     HbA1C (Haemoglobin A1C) blood test

Unlike the previous tests which take a snapshot of a few minutes or hours, the HbA1c is a clever test that gives you a picture of what your blood sugar levels look like over time.

Haemoglobin is a protein in your red blood cells and HbA1C is formed when glucose sticks to the haemoglobin. The more excess blood sugar, the more HbA1C is formed. Because your red blood cells live for around three to four months, they keep a diary of what’s been going on with your blood sugar levels for some time. This makes the HbA1C test a very useful one for confirming suspected diabetes.

The HbA1c  involves having blood taken, but there’s no need to fast beforehand. The results are a percentage, and below 5.7% is considered normal, while 6.5% and higher in more than one test could indicate diabetes, according to Medi-Clinic.

As well as diagnosing diabetes, the HbA1C is another important test for people with Type 1 and Type 2 diabetes. With diabetes, balance is everything: the goal is 7% or below for your HbA1c, although that is hard for many people.

It’s important to have one every three to six months – here are 10 fast facts about the HbA1c. Find out how continuous glucose monitoring can add more information to your HbA1C results, if you already have diabetes.

The numbers might seem overwhelming at first, and it might feel frustrating to retake tests you’ve already done. But try to be patient: with diabetes the more you know the better. Don’t forget to  join the Diabetic South Africans community for tips, advice and encouragement from people who are on the diabetes journey with you. You’re not alone in this!

What to read next?

How to reverse Type 2 diabetes: There is a ‘recipe’ for how to reverse Type 2 diabetes, and we’ve outlined it step-by-step here.

Type 2 diabetes risk factors: Spend 1 minute watching this video and you’ll know if you’re at risk of developing Type 2 diabetes.

What is normal blood sugar? Here are the numbers to aim for if you have diabetes – and what normal blood sugar looks like.

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Sweet Life is a registered NPO/PBO (220-984) with a single goal: to improve diabetes in South Africa. We are funded by sponsorships and donations from aligned companies and organisations who believe in our work. We only share information that we believe benefits our community. While some of this information is linked to specific brands, it is not an official endorsement of that brand. We believe in empowering people with diabetes to make the best decisions they can, to live a healthy, happy life with diabetes.