Hemoglobin A1c (HbA1c) Test for Diabetes

What is a Hemoglobin A1c (Average Blood Sugar) Test?

The Hemoglobin A1C Test  is also called HbA1c, glycated hemoglobin test, or glycoslated hemoglobin test is a common blood test used to diagnose type 1 and type 2 diabetes to determine how well your diabetes is being controlled. 

According to American Diabetes Association, the test result of A1c reflects your average blood sugar level for the past two to three months. Specifically, the A1C test measures what percentage of your hemoglobin (a protein in red blood cells that carries oxygen) is coated with sugar (glycated). The higher your A1C level, the poorer your blood sugar control and the higher your risk of diabetes complications. 

Why Hemoglobin A1c Test  is Done?

Based on the international committee of experts from the European Association for the Study of Diabetes, American Diabetes Association, and International Diabetes Federation stated that they recommends the A1C test as the primary test used to diagnose prediabetes, type 1 diabetes and type 2 diabetes.

A1C test can help you manage your diabetes:

• to determine if your treatment plan is working properly
• to confirm self-testing results or blood test results by the doctor.
• to show you how healthy choices can make a difference in diabetes.

How to Prepare A1c Test?

A1c Test is a quite simple blood test. You just eat and drink normally before the test.

Expect your the A1c test

During the test, the health care team practitioner simply takes a sample of blood by inserting a needle into a vein in your arm or pricking the tip of your finger with a small, pointed lancet. The blood sample is sent to a lab for analysis. You can return to your usual activities immediately.

The Results

After the blood analysis, the results conclude for someone who doesn't have diabetes, a normal A1C level can range from 4.5 to 6 percent. Someone who's had uncontrolled diabetes for a long time might have an A1C level above 8 percent.

When the A1C test is used to diagnose diabetes, an A1C level of 6.5 percent or higher on two separate tests indicates you have diabetes. A result between 5.7 and 6.4 percent is considered prediabetes, which indicates a high risk of developing diabetes.

For most people who have previously diagnosed diabetes, an A1C level of 7 percent or less is a common treatment target. Higher targets may be chosen in some individuals. If your A1C level is above your target, your doctor may recommend a change in your diabetes treatment plan. Remember, the higher your A1C level, the higher your risk of diabetes complications.

Here's how A1C level corresponds to average blood sugar level, in milligrams per deciliter (mg/dL) and millimoles per liter (mmol/L):

A1C level        Estimated average blood sugar level
5 percent        97 mg/dL (5.4 mmol/L)
6 percent        126 mg/dL (7 mmol/L)
7 percent        154 mg/dL (8.5 mmol/L)
8 percent        183 mg/dL (10.2 mmol/L)
9 percent        212 mg/dL (11.8 mmol/L)
10 percent        240 mg/dL (13.3 mmol/L)
11 percent        269 mg/dL (14.9 mmol/L)
12 percent        298 mg/dL (16.5 mmol/L)
13 percent        326 mg/dL (18.1 mmol/L)
14 percent        355 mg/dL (19.7 mmol/L)

What are the limitations?

Although the A1C test is an important tool, it can't replace daily self-testing of blood glucose for those who need it. A1C tests don't measure your day-to-day control. You can't adjust your insulin on the basis of your A1C tests. That's why your blood sugar checks and your log of results are so important to staying in effective control.

Source & References:

1. A1c Test - mayoclinic.com Retrieved last March 3, 2013
2. Living with Diabetes  - diabetes.org. Retrieved last March 3, 2013 
3. The Hemoglobin A1c (HbA1c) Test for Diabetes - webmd.com . Retrieved last March 3, 2013 
4. Image source: http://www.dlife.com/diabetes/export/pics/dLife_Images/A1C_Levels_p1.jpg. Retrieved last March 3, 2013

Read More

Type 1 Diabetes

Overview
Type 1 diabetes (also called juvenile-onset diabetes mellitus and insulin-dependent diabetes mellitus)  is occurs when the body's own immune system destroys the insulin- producing  beta cells of the pancreas. In this article, you'll learn the basics about type 1 diabetes, including symptoms and causes and complications.

Two forms of the Type 1 Diabetes

• Idiopathic type 1 - refers to rare forms of the disease with no known cause.
• Immune-mediated diabetes - an autoimmune disorder in which the body's immune system destroys, or attempts to destroy, the cells in the pancreas that produce insulin, Immune-mediated diabetes is the most common form of type 1 diabetes

Type 1 Diabetes and Insulin

Normally the hormone insulin is secreted by the pancreas in low amounts. When you eat a meal, sugar (glucose) from food stimulates the pancreas to release insulin. The amount that is released is proportional to the amount that is required by the size of that particular meal.

The main role of insulin is to help and move certain nutrients especially sugar or glucose  into the cells of the body's tissues. Cells use sugars and other nutrients from meals as a source of energy to function.

The amount of sugar in the blood decreases once it enters the cells. Normally that signals the beta cells in the pancreas to lower the amount of insulin secreted so that you don't develop low blood sugar levels (hypoglycemia). But the destruction of the beta cells that occurs with type 1 diabetes throws the entire process into disarray.

In people with type 1 diabetes, sugar isn't moved into the cells because insulin is not available. When sugar builds up in the blood instead of going into cells, the body's cells starve for nutrients and other systems in the body must provide energy for many important bodily functions. As a result, high blood sugar develops and can cause:

• Dehydration. The build up of sugar in the blood can cause an increase in urination (to try to clear the sugar from the body). When the kidneys lose the glucose through the urine, a large amount of water is also lost, causing dehydration.
• Weight loss. The loss of sugar in the urine means a loss of calories which provide energy and therefore many people with high sugars lose weight. (Dehydration also contributes to weight loss.)
• Diabetic ketoacidosis (DKA). Without insulin and because the cells are starved of energy, the body breaks down fat cells. Products of this fat breakdown include acidic chemicals called ketones that can be used for energy. Levels of these ketones begin to build up in the blood, causing an increased acidity. The liver continues to release the sugar it stores to help out. Since the body cannot use these sugars without insulin, more sugars piles into the blood stream. The combination of high excess sugars, dehydration, and acid build up is known as "ketoacidosis" and can be life-threatening if not treated immediately.
• Damage to the body. Over time, the high sugar levels in the blood may damage the nerves and small blood vessels of the eyes, kidneys, and heart and predispose a person to atherosclerosis (hardening) of the large arteries that can cause heart attack and stroke.

Incidence 
Type 1 diabetes can occur at any age, but it usually starts in people younger than 20. Symptoms are usually severe and occur rapidly.

The exact cause of type 1 diabetes is not known. Type 1 diabetes accounts for 3% of all new cases of diabetes each year. There is 1 new case per every 7,000 children per year. New cases are less common among adults older than 20. Accounting for only about 5% of the people with diabetes. The condition is more common in whites than in blacks and occurs equally in men and women.

Incidence varies from 8 to 17 per 100,000 in Northern Europe and the U.S. with a high of about 35 per 100,000 in Scandinavia to a low of 1 per 100,000 in Japan and China.

Causes
Diabetes type 1 is induced by one or more of the following:

• Genetic susceptibility - Doctors don't know all the factors that lead to type 1 diabetes. Clearly, the susceptibility to the condition can be inherited.
• Environmental -  Doctors have identified that an environmental trigger plays a role in causing the disease. Type 1 diabetes appears to occur when something in the environment -- a toxin or a virus 
• Diabetogenic trigger  - Some researchers believe that the cow's milk has been implicated as a possible trigger of the autoimmune response that destroys pancreatic beta cells in genetically susceptible hosts, thus causing diabetes mellitus. 
• Exposure to a driving antigen - Some chemicals and drugs preferentially destroy pancreatic cells that lead to loss of insulin production.

Symptoms
The classical symptoms of type 1 diabetes include:

• Increased thirst
• Increased hunger (especially after eating)
• Dry mouth
• Nausea and occasionally vomiting
• Abdominal pain
• Frequent urination
• Unexplained weight loss (even though you are eating and feel hungry)
• Fatigue (weak, tired feeling)
• Blurred vision
• Heavy, labored breathing (Kussmaul respiration)
• Frequent infections of the skin, urinary tract, or vagina

Image source: wikipedia.org

Before a person knows they have diabetes, blood sugar levels can be in a very high range for long periods of time which could cause diabetic ketoacidosis. These symptoms could be:

• Dry skin
• Rapid deep breathing
• Drowsiness
• Fruity smeel to the breath
• Abdominal pain
• Vomiting
• Loss of consciousness(rare)

Tests
The following tests can be used to diagnose diabetes:

• Urinalysis shows glucose and ketone bodies in the urine, but a blood test is required for diagnosis
• Fasting blood glucose is 126 mg/dL or higher
• Random (nonfasting) blood glucose exceeds 200 mg/dL (this must be confined with a fasting test)
• Insulin test (low or undetectable level of insulin)
• C-peptide test (low or undetectable level of the protein C-peptide, a by-product of insulin production)

Complications

Type 1 diabetes can cause different problems, but there are three key complications:

1. Hypoglycemia (low blood sugar; sometimes called an insulin reaction) occurs when blood sugar drops too low.
2. Hyperglycemia (high blood sugar) occurs when blood sugar is too high, and can be a sign that diabetes is not well controlled.
3. Ketoacidosis (diabetic coma) is loss of consciousness due to untreated or under-treated diabetes.

References

1. "Type 1 Diabetes Mellitus". Retrieved 2008-08-04.
2. "Type 1 Diabetes". Retrieved 2013-02-12
3. Kasper, Dennis L; Braunwald, Eugene; Fauci, Anthony; et al. (2005). Harrison's Principles of Internal Medicine (16th ed.). New York: McGraw-Hill. ISBN 0-07-139140-1.
4.  "content.nejm.org". content.nejm.org. Retrieved 29 February 2013.
5. "Endocrinology Health Guide".Retrieved 29 February 2013.

Read More