For People of African, 

Mediterranean, or 

Southeast Asian Heritage: 

Important Information about 

Diabetes Blood Tests

U.S. Department 

of Health and 

Human Services 

NATIONAL INSTITUTES OF HEALTH National Diabetes Information Clearinghouse

 

 

 

 

 

 

For People of African, 

Mediterranean, or 

Southeast Asian Heritage: 

Important Information about 

Diabetes Blood Tests 

U.S. Department 

of Health and 

Human Services 

NATIONAL INSTITUTES OF HEALTH National Diabetes Information Clearinghouse
 

 

 

 

 

 

 

 

Contents

Introduction ............................................................ 1

What are some common hemoglobin 

variants? ................................................................... 2

What is the A1C test? ............................................. 3

How do hemoglobin variants affect the A1C 

test and my diabetes care? ...................................... 3

How will I know whether I have a 

hemoglobin variant? ............................................... 4

Where can my health care provider 

find more information about hemoglobin 

variants and the A1C test? ..................................... 5

How can I know if my diabetes is well 

controlled if I have a hemoglobin variant? ............ 5

Points to Remember ............................................... 6

Hope through Research ......................................... 7

Pronunciation Guide .............................................. 7

For More Information ........................................... 8

For More Information about Sickle Cell 

Trait and Other Blood Conditions ....................... 8

Acknowledgments .................................................. 9
 

 

 

 

 

 

 

 

 

 

 

 

1 

Introduction 

If you are of African, Mediterranean, or Southeast 

Asian heritage, you could have a form of 

hemoglobin* in your red blood cells that affects 

your diabetes care. Hemoglobin in red blood cells 

gives blood its red color and carries oxygen from 

your lungs to all parts of your body. Some forms of 

hemoglobin can cause false results for a diabetes 

blood test called the A1C test. If the A1C test 

gives a false result, your health care provider may 

think your blood glucose, also called blood sugar, 

level is higher or lower than it really is. 

*See page 7 for tips on how to say the words in 

bold type. 

If you are of African, Mediterranean, or Southeast Asian 

heritage, you could have a form of hemoglobin in your red 

blood cells that affects your diabetes care.
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

What are some common hemoglobin 

variants? 

Most people have only one kind of hemoglobin, 

called hemoglobin A. Some people have 

both hemoglobin A and another kind, such as 

hemoglobin S, C, or E. These less common forms 

of hemoglobin are called hemoglobin variants. 

You can have a hemoglobin variant but not know it 

because you might not have any symptoms of blood 

disease. Having a variant without health problems 

is also called having the trait or being a carrier. 

One condition caused by hemoglobin S is sickle 

cell trait, which occurs most often in people of 

African heritage. Having the trait means you 

inherited a gene for the hemoglobin variant from 

one parent. Genes carry information about which 

features are passed down from parents to children. 

People with sickle cell trait usually have no health 

problems. Inheriting genes from both parents for 

the variant hemoglobin S, however, results in sickle 

cell disease, which is painful. You would know if 

you or your child had sickle cell disease. 

People of Mediterranean or Southeast Asian 

heritage also can inherit hemoglobin variants. 

Some of these variants cause no health problems; 

others cause some problems. Having a hemoglobin 

variant does not increase your risk for diabetes. 

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What is the A1C test? 

The A1C blood test, also called the hemoglobin 

A1C test, HbA1c, or glycohemoglobin test, reflects 

your average blood glucose levels for the past 

3 months. Your health care provider will send you 

to a lab to have a small sample of your blood drawn 

for the test. Your health care provider might use 

the A1C test to diagnose your diabetes. After 

being diagnosed with diabetes, you should have 

the A1C test at least twice a year. Your health 

care provider uses the results of your A1C tests 

to see whether you need to make changes in your 

diabetes medicine, meal plan, or physical activity 

routine to keep your diabetes under control. 

How do hemoglobin variants affect 

the A1C test and my diabetes care? 

A variant form of hemoglobin in your blood can 

give you false A1C test results. If your test result 

is falsely high, your health care provider might 

think that you have diabetes when you don’t. 

Your health care provider might also change your 

diabetes medicine or make other changes in how 

you take care of your diabetes based on false A1C 

test results. These changes could cause low blood 

glucose, or hypoglycemia. 

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If your test result is falsely low, your health care 

provider might make changes in your treatment 

that could cause your blood glucose to stay too 

high, increasing your risk for diabetes problems in 

your eyes, nerves, and kidneys. Not all A1C tests 

are affected by variant hemoglobin. Your health 

care provider can take steps to make sure you get 

accurate results from your A1C test. 

How will I know whether I have a 

hemoglobin variant? 

Many people with hemoglobin variants have no 

health problems. You might be at risk for having a 

hemoglobin variant if 

●	 you are of African, Mediterranean, or Southeast 

Asian heritage 

●	 members of your family have sickle cell trait or 

sickle cell anemia 

●	 the results of your blood glucose test or selfmonitoring of blood glucose don’t match the 

results of your A1C test 

●	 your A1C result is different than expected 

●	 your A1C result is very high—above 15 percent 

●	 your most recent A1C result is very different from 

your last A1C result 

Your health care provider can order other blood tests 

to confirm whether you have a hemoglobin variant. 

4 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Where can my health care provider find 

more information about hemoglobin 

variants and the A1C test? 

Your health care provider can access a fact sheet 

that explains the limitations of the A1C test online 

at www.diabetes.niddk.nih.gov or by calling the 

National Diabetes Information Clearinghouse at 

1–800–860–8747. 

How can I know if my diabetes is well 

controlled if I have a hemoglobin 

variant? 

Some A1C tests give accurate results in people 

with a hemoglobin variant. Your health care 

5 

provider can arrange for your A1C test to be done 

at a lab that gives accurate results for people with a 

hemoglobin variant. Your daily blood glucose tests 

can also show how well controlled your diabetes is, 

but keep in mind that each blood glucose test gives 

information for only one point in time. 
Points to Remember 

●	 If you are of African, Mediterranean, or 

Southeast Asian heritage, you are at risk for 

having a hemoglobin variant—a less common 

form of hemoglobin. 

●	 You can have a hemoglobin variant but not 

know it. 

●	 Having a hemoglobin variant does not increase 

your risk for diabetes, but it can affect your 

diabetes test results. 

●	 A variant form of hemoglobin in your blood 

can give you false A1C test results. The results 

might show that your average blood glucose level 

is higher or lower than the actual level. 

●	 Your health care provider can arrange for your 

A1C test to be done at a lab that gives accurate 

results for people with a hemoglobin variant. 

●	 Your daily blood glucose tests can also show how 

well controlled your diabetes is, but keep in mind 

that each blood glucose test gives information 

for only one point in time. 

6 
 

 

 

 

 

 

 

 

 

Hope through Research 

The NIDDK conducts and supports research 

related to the causes, treatment, and prevention of 

diabetes. 

Participants in clinical trials can play a more 

active role in their own health care, gain access to 

new research treatments before they are widely 

available, and help others by contributing to 

medical research. For information about current 

studies, visit www.ClinicalTrials.gov.

Pronunciation Guide 

glycohemoglobin (GLY-koh-HEE-moh-GLOH-bin) 

hemoglobin (HEE-moh-GLOH-bin) 

hemoglobin variants (HEE-moh-GLOH-bin) 

(VAIR-ee-uhnts) 

hypoglycemia (HY-poh-gly-SEE-mee-uh) 

sickle cell trait (SIH-kul) (sel) (trayt) 

7 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

For More Information 

American Diabetes Association 

1701 North Beauregard Street 

Alexandria, VA 22311 

Phone: 1–800–DIABETES (1–800–342–2383) 

Fax: 703–549–6995 

Email: AskADA@diabetes.org 

Internet: www.diabetes.org 

For More Information about Sickle Cell 

Trait and Other Blood Conditions 

National Heart, Lung, and Blood Institute 

Health Information Center 

P.O. Box 30105 

Bethesda, MD 20824–0105 

Phone: 301–592–8573

Fax: 240–629–3246 

Email: nhlbiinfo@nhlbi.nih.gov 

Internet: www.nhlbi.nih.gov

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Acknowledgments 

Publications produced by the Clearinghouse are 

carefully reviewed by both NIDDK scientists and 

outside experts. This publication was originally 

reviewed by Randie R. Little, Ph.D., National 

Glycohemoglobin Standardization Program, 

University of Missouri School of Medicine. 

National Diabetes Education Program 

1 Diabetes Way 

Bethesda, MD 20814–9692 

Phone: 1–888–693–NDEP (1–888–693–6337) 

TTY: 1–866–569–1162 

Fax: 703–738–4929 

Email: ndep@mail.nih.gov 

Internet: www.ndep.nih.gov 

www.yourdiabetesinfo.org 

The National Diabetes Education Program is a 

federally funded program sponsored by the U.S. 

Department of Health and Human Services’ 

National Institutes of Health and the Centers for 

Disease Control and Prevention and includes over 

200 partners at the federal, state, and local levels, 

working together to reduce the morbidity and 

mortality associated with diabetes. 

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National Diabetes 

Information Clearinghouse 

1 Information Way

Bethesda, MD 20892–3560

Phone: 1–800–860–8747

TTY: 1–866–569–1162

Fax: 703–738–4929

Email: ndic@info.niddk.nih.gov

Internet: www.diabetes.niddk.nih.gov

The National Diabetes Information Clearinghouse (NDIC) is 

a service of the National Institute of Diabetes and Digestive 

and Kidney Diseases (NIDDK). The NIDDK is part of the 

National Institutes of Health of the U.S. Department of Health 

and Human Services. Established in 1978, the Clearinghouse 

provides information about diabetes to people with diabetes and 

to their families, health care professionals, and the public. The 

NDIC answers inquiries, develops and distributes publications, 

and works closely with professional and patient organizations and 

Government agencies to coordinate resources about diabetes. 

This publication is not copyrighted. The Clearinghouse 

encourages users of this publication to duplicate and distribute 

as many copies as desired. 

This publication is available at www.diabetes.niddk.nih.gov.

This publication may contain information about medications. 

When prepared, this publication included the most current 

information available. For updates or for questions about any 

medications, contact the U.S. Food and Drug Administration 

toll-free at 1–888–INFO–FDA (1–888–463–6332) or visit 

www.fda.gov. Consult your health care provider for more 

information. 
U.S. DEPArTMENT OF HEALTH 

AND HUMAN SErvICES 

National Institutes of Health 

NIH Publication No. 12–6283 

October 2011 

The NIDDK prints on recycled paper with bio based ink.