What forms of tests are available for Diabetes control?

A. Fasting Blood Sugar

This is a common test because it is easy to perform. After fasting overnight, you have your blood drawn at an early morning doctor/s visit and tested to see if your blood sugar is in the normal range.

Normal result: 70 – 99 milligrams per decilitre (mg/dL) or less than 5.5.mmol/L

B. Urine Glucose Test

The glucose urine test measures the amount of sugar (glucose) in a urine sample. The presence of glucose in the urine is called glucosuria.

C. Two-hour Postprandial Test

This blood test is done two hours after you have eaten.

Normal result: 70 – 145 mg/dL (less than 7.9 mmol/L)

D. Oral Glucose Tolerance Test

A glucose tolerance test (OGTT) is the administration of glucose to determine how quickly it is cleared from the blood. The test is usually used to test for diabetes, insulin resistance, and sometimes, reactive hypoglycemia. With an oral glucose tolerance test, the person fasts overnight (at least 8 but not more than 16 hours). First, the fasting plasma glucose is tested. After this test, the person receives 75 grams of glucose (100 grams for pregnant women). Usually, the glucose is in a sweet-tasting liquid that the person drinks. Blood samples are taken up to four times to measure the blood glucose.

What does the glucose tolerance test measure?

The classic oral glucose tolerance test measures blood glucose levels five times over a period of three hours. Some physicians simply get a baseline blood sample followed by a sample two hours after drinking the glucose solution. In a person without diabetes, the glucose levels rise and then fall quickly. In someone with diabetes, glucose levels rise higher than normal and fail to come back down as fast.

People with glucose levels between normal and diabetic have impaired glucose tolerance (IGT). People with IGT do not have diabetes.

How are the results of the glucose tolerance test evaluated?

Glucose tolerance tests may lead to one of the following diagnosis:

Normal response: A person is said to have a normal response when the 2-hour glucose level is less than 140 mg/dl.

Impaired glucose tolerance: A person is said to have IGT when the fasting plasma glucose is less than 126 mg/dl and the 2-hour glucose level is between 140 and 199 mg/dl.

Diabetes: A person has diabetes when two diagnostic tests done on different days show that the blood glucose level is high

E. Intravenous Glucose Tolerance Test (IGTT)

For the intravenous glucose tolerance test, glucose is injected into your vein for 3 minutes. Blood insulin levels are measured before the injection, and again at 1 and 3 minutes after the injection.

F. Glycosylated Haemoglobin Test (HbA1C)

The Haemoglobin A1c test, also called HbA1c, glycated haemoglobin test or glycohemoglobin, is an important blood test used to determine how well your diabetes is being controlled. Haemoglobin A1c provides an average of your blood sugar control over a six to twelve week period and is used in conjunction with home blood sugar monitoring to make adjustments in your diabetes medicines.

Haemoglobin is a substance within red blood cells that carries oxygen throughout your body. When your diabetes is not controlled (meaning that your blood sugar is too high), sugar builds up in your blood and combines with your haemoglobin, becoming ‘glycated’. Therefore, the average amount of sugar in your blood can be determined by measuring a haemoglobin A1c level. If your glucose levels have been high over recent weeks, your haemoglobin A1c test will be higher. The amount of haemoglobin A1c will reflect the last several weeks of blood sugar levels, typically encompassing a period of 120 days.

What’s a Normal Haemoglobin A1c test?

For people without diabetes, the normal range for the haemoglobin A1c test is between 4% and 6%. As studies have repeatedly shown that out-of-control diabetes results in complications from the disease, the goal for people with diabetes is an haemoglobin A1c less than 7%. The higher the haemoglobin A1c, the higher the risks of developing complications related to diabetes.

People with diabetes should have this test every three months to determine whether their blood sugars have reached the target level of control. Those who have their diabetes under good control may be able to wait longer between the blood tests but experts recommend checking at least two times a year.

Patients with diseases affecting haemoglobin such as anaemia may get abnormal results with this test. Other abnormalities that can affect the results of the haemoglobin A1c include supplements such as Vitamins C and E, and high cholesterol levels. Kidney disease and liver disease may also affect the result of the haemoglobin A1c test.

G. Self-Monitoring Blood Glucose Test (SMBG)

To do SMBG, a tiny drop of blood is taken and a glucose meter is used to measure your blood glucose level.