Islets of Hope treatment options for persons with diabetes

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Hemoglobin A1c (HbA1c) Test - $ 24.95

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Article disclaimer

Article by Lahle Wolfe. For permission to use this article please contact:  Editor@isletsofhope.com.

Sources:
LabtestsOnline.org
Wikipedia.com
Children with Diabetes


Diabetes Treatment & Management
Diabetes Type 1
Diabetes Type 2 
Pre-Diabetes
Gestational Diabetes
Diabetes Insipidus
Treating Hypoglycemia
Treating Hyperglycemia
Monitoring Blood Sugar
Diabetes Complications

How to Give a Glucagon Shot (illustrated)


Conventional Treatments
Pancreas Islet Cell Transplant
Pancreas (Organ) Transplant
Stress Management
Lifestyle Changes


Complimentary Treatments
Alternative & Complementary Mini Site Index
Acupuncture
Biofeedback, Meditation & Prayer
Chiropractic Care
Diabetes "Cures"
Herbals & Natural Remedies
Homeopathy
Vitamins and Supplements
Yoga


Lifestyle Approaches to Diabetes Management
Diabetes and Exercise
Diabetes and Sports
Diabetes & Diet/Meal Planning
Stress Management     


Case Study: Potential Pitfalls of Using HbA1c as the Sole Measure of Glycemic Control  - Two instances where persons were diabetic, but reassured they were not based on falsely low HbA1c test results. Both patients were, however, diabetic.


What are normal and target blood glucose ranges? 

Print Blood Glucose
Reference Guide


Diabetes Care Tips Blood Glucose Monitoring

Meters: How They Work and Meter Features

Alternative Testing Sites

Why Should I Test My Blood Glucose?

When Should I Test My Blood Glucose?

Meter Accuracy

Non-Invasive Blood Glucose Monitoring Devices


Target HbA1c Levels

Target for most people with diabetes:  At or below 7%

Time to make changes in your diabetes care plan:  8.0 (8%) or higher, or lower than 4.7%.


 Interested in learning more about home HbA1c testing?

Rick Mendosa's diabetes website offers a comparison of home test kits.


Blood Sugar Conversion Tool

Convert mmol/L to mg/dL (or vice versa)


The BD Diabetes website explains the HbA1c test this way:

"When glucose is in the blood stream waiting to be used by the cells, some of it can become permanently attached to red blood cells. The attachment occurs at the same part of the red blood cell that carries oxygen, called the hemoglobin molecule, but does not affect the cell's ability to carry oxygen.  In the absence of diabetes, the body takes glucose efficiently into the cells, so there is usually very little free glucose available to attach to hemoglobin. In that case, the hemoglobin A1c level stays around 4 to 6 percent, which means that only 4 to 6 percent of red blood cells have glucose attached to them.

"When you have diabetes ... you end up with an excess amount of free blood glucose. More glucose in the blood means more glucose attaching to the red blood cells, and that's why the HbA1c level in a person with untreated diabetes may be as high as 10 percent or more. The higher your HbA1c test results, the greater the amount of sugar in your blood. And high blood sugar over a long period of time may increase your risk of diabetes complications."


What is a CBC?

A complete blood count (CBC) is a test that  measures many things:

- The number of red blood cells (RBCs)

- The number of white blood cells (WBCs)

- The total amount of hemoglobin in the blood. Hemoglobin (Hb), a protein that is the main component of red blood cells, carries oxygen from the lungs to the body's tissues, and carbon dioxide from the tissues to the lungs, to be exhaled.

- Hematocrit - the fraction of the blood composed of red blood cells

- The mean corpuscular volume (MCV) -- the size of the red blood cells (this is important because misshapen blood cells can produce false results in some types of tests)

CBC tests also provides information about:

- MCH (mean corpuscular hemoglobin)

- MCHC (mean corpuscular hemoglobin concentration)

- The platelet count is also usually included in the CBC.


Are HbA1c tests more accurate than fructosamine tests?  

Studies vary...

Falsely high glycated haemoglobin [HbA1c] because of haemoglobin OSU-Christiansborg

Are they comparable?  A study in the comparison of fructosamine with glycosylated hemoglobin and plasma proteins as measures of glycemic control.  

HbA1c superior to fructosamine testing in pediatric use:  Fructosamine and glycated haemoglobin in the assessment of long term glycaemic control in diabetes.

islets of hope diabetes medical library                 main "Treatment Information" page
Diabetes treatment - tests                                                                        main Diabetes Tests page

Glycosylated hemoglobin test                        print this article
(also called
HbA1c Test, Hemoglobin - glycosylated, A1c, GHb, Glycohemoglobin)


Mini Site Index
What is an HbA1c test?
How is the test done?
How often should I have an HbA1c done?
Why can't I just perform HbA1c home tests?
What do the test results show?
What HbA1c level is considered "good" for persons with diabetes?
HbA1c Results and Equivalent Average Blood Glucose Level (Chart)
When might an HbA1c not be accurate?

Note:  You might also be interested in reading about another test to monitor glucose control called the "fructosamine test." This test may be used instead of, or in addition to an HbA1c test for women with diabetes that become pregnant, or those that have recently had a major change in their diabetes care plan.  The fructosamine test measures glucose control over the previous 2-3 weeks and may be used to determine how blood glucose (blood sugar) control is being affected after recent changes in care plans sooner than an HbA1c test could show.

A fructosamine test might also be ordered when there is some medical condition that affects the average age of red blood cells (RBCs).  See more detail at the bottom of this article under "When might an HbA1c not be accurate?"

What is an HbA1c test?

You are probably familiar with daily blood glucose testing.  Another test for blood glucose, the HbA1c (hemoglobin A1c test, shows what your overall blood glucose was for the past 3 months.  It is not performed each day, but should be done 2-4 times per year at your doctor's office.  The HbA1c test measures the amount of glycosylated hemoglobin in your blood, or, more simply put, this test shows how much glucose is sticking to your red blood cells.

Your doctor does this test to see what your blood glucose is most of the time (an average of overall glucose control).


How is the test done?

HbA1c tests can easily be done with just a regular finger stick, just like testing for blood glucose.  Home tests are now available too, but should not be used as a substitute for the one that your doctor performs.  There is no risk of getting AIDS, hepatitis, or any other blood-borne disease from this test.


How often should I have an HbA1c done?

The American Diabetes Association (ADA) recommends having an HbA1c test done at your doctor's office or a lab every 3 months.  Also, red blood cells (which bind with glucose) only live in the body for about 90 days, which is why the HbA1c test needs to be done several times a year.  


Why can't I just perform home HbA1c tests?

You can use home test kits in between doctor visits but there are at least three good reasons why you should not use them as a substitute for the one your doctor performs:

  • Home HbA1c tests are very particular and subject to inaccuracy if the test is not conducted exactly as stated in the instructions.
     
  • A home HbA1c test cannot offer you the advice that your doctor can on how to make adjustments in your diabetes care plan.
     
  • If you ever decide to consider insulin pump therapy, your doctor needs to have HbA1c information in your medical records to satisfy the requirements of many insurance companies as well as Medicare and Medicaid programs.


What do the test results show?

The HbA1c test result represents an average for the previous 1-3 months of  your free blood glucose level.   Your blood glucose  level goes up and down throughout the day and the specific amount of glucose in the blood at any given time is known as your "free blood glucose level."  An HbA1c test suggests and average of glycemic control over the previous 120 days (red blood cells and the hemoglobin they contain have an average life span of 120 days).

Normally, only a small percentage of the hemoglobin (Hb) molecules in red blood cells become chemically linked (glycosylated ) to glucose (sugar).  The glucose "sticks" or binds (glycosylates) to the red blood cells and these cells can be counted.  The number of glycosylated blood cells increases over time, and the more often you have high blood glucose, the higher your HbA1c test results will be.  Remember, the hemoglobin in red blood cells that fuses with glucose can be measured up to 120 days later so an occasional high or low here and there will not have a dramatic impact on your HbA1c, but chronic blood glucose problems will.

The HbA1c is an important tool for you and your doctor to help determine how well you are managing your care over the long-haul.  It also can help predict the level of risk for developing longer-term diabetes complications.  But you should also know that you can have high blood glucose on some days and low blood glucose on others, and the average could create a misleading "good" HbA1c reading.  Those "bad"days can still be unhealthy and create risk factors for problems like diabetic neuropathy and retinopathy.  

For example, if you run high all day long but low all night long, your average HbA1c might be in an acceptable range.  But running high -- even if your HbA1c is good is still not good for you.  This is why it is so important to check your blood glucose at least 5 times a day.  Unless you check your blood glucose often, you may never know that you are running too high at certain times of the day until your HbA1c comes back high.


What HbA1c level is considered "good" for persons with diabetes?

Your HbA1c percentage rises as your average blood glucose level rises. The normal range for a person without diabetes is 4 to 6%. Your doctor should determine what your target HbA1c should be.  For some, this means 6% or lower, for others (like the very elderly) a recommended target may be slightly higher than 7%.  But for most people with diabetes the American Diabetes Association (ADA) recommends targeting for an HbA1c of 7% or less.  

Generally, a result of 7.0 (7%) or lower usually means that your blood glucose is under control (keep up the good work!).  If your HbA1c is 8.0 (8%) or higher, it means that your blood glucose may be too high and you are at an increased risk for developing diabetes complications. You may need a change in your meal plan, physical activity plan, or diabetes medications, or insulin.

IOH Health Tip:  It is important to continue to test your blood glucose on a daily basis.  An HbA1c is not a substitute for daily glucose monitoring, and daily glucose monitoring is not a substitute for having an HbA1c done.  Also, keep in mind that the test averages blood glucose levels.  If you are hypoglycemic through the night but high during the day your diabetes is still out of control but your average on the HbA1c may be acceptable.  This is because frequent lows (which are not a good thing) can bring down the overall average.

Your doctor needs to look at your blood glucose log and compare your records with your HbA1c results in order to determine if you need changes in your diabetes care plan.

HbA1c Results and Equivalent Average Blood Glucose Level

HbA1c
Test Result

Average
Blood Glucose
in mg/dL

Average
Blood Glucose in
mmol/L

Notes

4%

65

3.61

Blood glucose average too low for persons with diabetes (1)

5%

100

5.5

Blood glucose may be too tightly controlled(1)

6%

135

6.6

Blood glucose very well managed

7%

170

8.3

Blood glucose very well managed

8%

205

10.0

Marginally managed, take action to lower

9%

240

11.6

Poorly managed, corrective action required

10%

275

13.3

Poorly managed, corrective action required

11%

310

17.2

Poorly managed, corrective action required

12%

345

19.16

Very poorly manage, corrective action required

13%

380

21.2

Very poorly manage, corrective action required

    Chart Note:  (1) An HbA1c for a person with diabetes lower than 4.7 is too low (some consider lower than 5.0 as being too low).  The risk of loss of consciousness, insulin shock, seizure, coma, and death from hypoglycemia for a person with diabetes increases significantly when an HbA1c falls below 5.0.  According to the Diabetes Monitor, "...if your HbA1c is above 10%, there's plenty of room for improvement.  If it's 6.5% that's pretty good.  5.9% would be classed as excellent."

    See Minimed's chart of risks associated with low HbA1c levels.


Studies, including  
The Diabetes Control and Complications Trial (DCCT, show that keeping your HbA1c at or below 7% (7.0 on the test scale) is associated with a dramatic reduction in risk for developing long-term diabetes complications.  Other studies that address amputation (the need for amputation, and surgical outcome) clearly show that HbA1c results have a strong impact on a patients outcome post-surgery.  HbA1c levels also have a direct impact on how well chronic infections heal, and whether or not gangrene will result.

A high HbA1c always indicates glucose control problems, but remember, a low reading may also indicate frequent hypoglycemia (low blood glucose) episodes are "balancing" the high blood glucose levels.  Be sure to keep daily records of your blood glucose levels because your doctor needs information from both HbA1c levels as well as daily glucose readings to help you manage your diabetes.


When might an HbA1c test not be accurate?

If a patient's HbA1c conflicts with self blood glucose monitoring (SBGM) the HbA1c test might not be an accurate reflection of overall blood glucose control.  For example, if a person has many SBGM readings in the 300-400s and an HbA1c of 6% the two do not reconcile and there may be a medical condition affecting the test results.

Your doctor may wish to check your creatinine levels and do a CBC test (complete blood count, see sidebar on left).  A high creatinine level can indicate renal (kidney) impairment which can lead to anemia; people that are anemic can have false, lower HbA1c readings.  

Also, incorrect blood specimen handling that causes red blood cell (RBC) destruction (hemolysis) can produce false, lower HbA1c results.

Low numbers of red blood cells (RBCs) can affect HbA1c results and may indicate, or be caused by:

  • Anemia from blood loss, hemorrhage, malnutrition, reactions to certain medications, certain diseases, bone marrow problems, iron deficiency, etc.
  • Bone marrow failure (for example, from radiation, toxin, fibrosis, tumor)
  • Erythropoietin deficiency (secondary to renal disease)
  • Hemolysis (RBC destruction)
  • Hyperthyroidism
  • Leukemia
  • Severe burns with loss of protein fluid
  • Multiple myeloma (a cancer that causes excessive growth and malfunction of plasma cells in the bone marrow.)
  • Malnutrition (nutritional deficiencies of iron, folate, vitamin B12, or vitamin B6)

Low hematocrit (see sidebar on left) may indicate, or be caused by, all of the above as well as the possibility of rheumatoid arthritis.

Low hemoglobin values may indicate, or be caused by:

  • Hemolysis (RBC destruction)
  • Anemia from blood loss, hemorrhage, malnutrition, reactions to certain medications, certain diseases, bone marrow problems, iron deficiency, etc.
  • Erythropoietin deficiency (secondary to renal disease)
  • Lead poisoning
  • Malnutrition
  • Nutritional deficits of iron, folate, vitamin B-12, vitamin B-6
  • Overhydration (too much fluid in the body; opposite of dehydration)

Conversely, a high hematocrit and high RBC can provide falsely elevated HbA1c test results.

An interesting study... If the Numbers Don't Fit... Discrepancies Between Glucose Meter Readings and HbA1c Reveal Stress of Living With Diabetes

Islets of Hope Health Tip:  Remember, your doctor needs the information from your daily diabetes log to compare with the results of your HbA1c.  An HbA1c not only can help determine how well you are controlling your blood glucose during the previous months, but an HbA1c that does not seem to agree with the daily diabetes log can also serve as a tool to indicate other problems your doctor may want to investigate further.

Links to More Information about HbA1c Tests

ABCs of hemoglobin A1c testing
HbA1c — the 7% Solution
Hemoglobin A1c quiz

 

   

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Page Updated 07/24/2006