Proceeds from website advertising help sustain Lab Tests Online. AACC is a not-for-profit organization and does not endorse non-AACC products and services.

Hemoglobinopathy Evaluation

Print this article
Share this page:
Also known as: Hemoglobin Evaluation; Hb ELP; Hb IEF; Sickle Cell Screen; Hemoglobin Fractionation
Formal name: Hemoglobin Electrophoresis; Hemoglobin Isoelectric Focusing; Hemoglobin by HPLC

At a Glance

Why Get Tested?

To investigate hemoglobinopathy as the cause of signs and symptoms; to screen for a hemoglobin disorder

When to Get Tested?

As follow up to abnormal results on a complete blood count (CBC) and/or blood smear; when you have symptoms of hemolytic anemia such as weakness and fatigue and your doctor suspects that you have an abnormal form of hemoglobin (hemoglobinopathy); when you have a family history of hemoglobinopathy; as part of newborn screening

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?


The Test Sample

What is being tested?

A hemoglobinopathy is an inherited blood disorder in which an individual has an abnormal form of hemoglobin (variant) or decreased production of hemoglobin (thalassemia). A hemoglobinopathy evaluation is a group of tests that identifies abnormal forms of or suggests problems with production of hemoglobin in order to screen for and/or diagnose a hemoglobin disorder.

Hemoglobin (Hb) is the iron-containing protein found in all red blood cells (RBCs) that binds to oxygen in the lungs and allows RBCs to carry the oxygen throughout the body, delivering it to the body's cells and tissues. Hemoglobin consists of one portion called heme, which is the molecule with iron at the center, and another portion made up of four globin (protein) chains. The globin chains, depending on their structure, have different designations: alpha, beta, gamma, and delta. The types of globin chains that are present are important in the function of hemoglobin and its ability to transport oxygen.

Normal hemoglobin types include:

  • Hemoglobin A: makes up about 95%-98% of Hb found in adults; it contains two alpha and two beta protein chains.
  • Hemoglobin A2:  makes up about 2%-3% of Hb in adults; it has two alpha and two delta protein chains.
  • Hemoglobin F (fetal hemoglobin): makes up to 1%-2% of Hb found in adults; it has two alpha and two gamma protein chains. This is the primary hemoglobin produced by the fetus during pregnancy; its production usually falls shortly after birth and reaches adult levels by 1-2 years.

Hemoglobinopathies occur when changes (mutations) in the genes that code for the globin chains cause alterations in the proteins. These genetic changes may result in a reduced production of one of the normal globin chains or in the production of structurally altered globin chains. Genetic mutations may affect the structure of the hemoglobin, its behavior, its production rate, and/or its stability. The presence of abnormal hemoglobin within RBCs can alter the appearance (size and shape) and function of the red blood cells.

Red blood cells containing abnormal hemoglobin (hemoglobin variants) may not carry oxygen efficiently and may be broken down by the body sooner than usual (a shortened survival), resulting in hemolytic anemia. Some of the most common hemoglobin variants include hemoglobin S, the primary hemoglobin in people with sickle cell disease that causes the RBC to become misshapen (sickle), decreasing the cell's survival; hemoglobin C, which can cause a minor amount of hemolytic anemia; and hemoglobin E, which may cause no symptoms or generally mild symptoms.

Thalassemia is a condition in which a gene mutation results in reduced production of one of the globin chains. This can upset the balance of alpha to beta chains, causing abnormal hemoglobin to form (alpha thalassemia) or causing an increase of minor hemoglobin components, such as Hb A2 or Hb F (beta thalassemia).

Many other less common hemoglobin variants exist. Some are silent – causing no signs or symptoms – while others affect the function and/or stability of the hemoglobin molecule. An investigation of a hemoglobin disorder typically involves tests that determine the types and amounts of hemoglobin present in a person's sample of blood. Some examples include:

  • Hemoglobin solubility test: used to test specifically for hemoglobin S, the main hemoglobin in sickle cell disease
  • Hemoglobin electrophoresis (Hb ELP)
  • Hemoglobin isoelectric focusing ( Hb IEF)
  • Hemoglobin by high performance liquid chromatography (HPLC)

Information from these tests, along with results from routine tests such as a complete blood count (CBC) and blood smear, aid in establishing a diagnosis.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test

Common Questions

Ask a Laboratory Scientist

Form temporarily unavailable

Due to a dramatic increase in the number of questions submitted to the volunteer laboratory scientists who respond to our users, we have had to limit the number of questions that can be submitted each day. Unfortunately, we have reached that limit today and are unable to accept your inquiry now. We understand that your questions are vital to your health and peace of mind, and recommend instead that you speak with your doctor or another healthcare professional. We apologize for this inconvenience.

This was not an easy step for us to take, as the volunteers on the response team are dedicated to the work they do and are often inspired by the help they can provide. We are actively seeking to expand our capability so that we can again accept and answer all user questions. We will accept and respond to the same limited number of questions tomorrow, but expect to resume the service, 24/7, as soon as possible.

Article Sources

« Return to Related Pages

NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Harmening D. Clinical Hematology and Fundamentals of Hemostasis, Fifth Edition. F.A. Davis Company, Philadelphia, 2009, Chapters 11 and 12.

Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. McPherson R, Pincus M, eds. Philadelphia, PA: Saunders Elsevier: 2007, Pp 520-522.

Clarke, W. and Dufour, D. R., Editors (2006). Contemporary Practice in Clinical Chemistry. AACC Press, Washington, DC, Pp 213-224.

(February 8, 2012) MedlinePlus Medical Encyclopedia. Hemoglobin electrophoresis. Available online at Accessed December 2012.

(October 5, 2011) Cheerva A. Alpha Thalassemia. Medscape Review article. Available online at through Accessed December 2012.

(January 3, 2012) Maakaron J. Sickle Cell Anemia. Medscape Review article. Available online at through Accessed December 2012.

(May 16, 2012) Carter S. Hemoglobin C Disease. Medscape Reference Article. Available online at through Accessed December 2012.

(©2012 University of Rochester) Health Encyclopedia. Sickle Cell Disease. Available online at through Accessed December 2012.

(©2012 University of Rochester) Health Encyclopedia. Alpha Thalassemia. Available online at through Accessed December 2012.

(©2012 University of Rochester) Health Encyclopedia. Beta Thalassemia. Available online at through Accessed December 2012.

(©2012 Mayo Medical Laboratories) Test Catalog. Thalassemia and Hemoglobinopathy Evaluation. Available online at through Accessed December 2012.

(Published online August 2011) Kohne E. Hemoglobinopathies. Dtsch Arztebl Int. 2011 August; 108(31-32): 532–540. Available online at through Accessed December 2012.

(©2013 St. Jude Children's Research Hospital) Hemoglobin C Trait. Available online at through Accessed February 2013.

(September 16, 2011) Centers for Disease Control and Prevention. Sickle Cell Disease, Data and Statistics. Available online at through Accessed February 2013.