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Test ID: Hgb Ele
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Hemoglobin Electrophoresis
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Useful For
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Hemoglobin electrophoresis (hemoglobinopathies screening test) is used as a screening method to detect quantitative or qualitative defects (variant hemoglobins) of globin chain synthesis, such as thalassemias (alpha, beta, gamma/delta, etc) and variant hemoglobins (i.e: Hb S, Hb C, Hb D, etc)
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Method name and description
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The variant II Beta-thalassemia short program is intended for the separation and percent determinations of hemoglobins A2 and F and as an aid in the identification of abnormal hemoglobins in whole blood using ion-exchange High Performance Liquid Chromatography (HPLC). Hemolysate of whole blood is injected into an analysis stream passing through a cartridge containing diethylaminomethyl-resin using high-performance liquid chromatography (HPLC). A preprogrammed gradient controls the elution buffer mixture that also passes through the analytical cartridge. The ionic strength of the elution buffer is raised by increasing the percentage of a second buffer. As the ionic strength of the buffer increases the more strongly retained hemoglobin’s elute from the cartridge. Absorbance changes are detected by a dual-wavelength filter photometer. Changes in absorbances are displayed as a chromatogram of absorbances versus time. Each hemoglobin has its own period of time before it appears in the eluate (Retention time).
Hbs are provisionally identified by their retention time and are quantified by computing the area under the corresponding peak in the elution profile.
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Reporting name
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Hemoglobin Electrophoresis
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Clinical information
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Hemoglobin is the iron-containing protein compound within red blood cells that carries oxygen throughout the body. It is made up of heme and globin chains. The globin protein consists of chains of amino acids, there are several different types of globin chains, named alpha, beta, delta, and gamma. Normal hemoglobin types include:
• Hemoglobin A :makes up about 98% of hemoglobin found in adults; it contains two alpha (α) chains and two beta (β) chains.
• Hemoglobin A2 : makes up about 3% of hemoglobin found in adults; it has two alpha (α) and two delta (δ) chains.
• Hemoglobin F (Hb F, fetal hemoglobin): makes up to 1%-2% of hemoglobin found in adults; it has two alpha (α) and two gamma (γ) chains. It is the primary hemoglobin produced by the fetus during pregnancy; its production usually falls shortly after birth and reaches adult level within 1-2 years.
Genetic changes (mutations) in the globin genes cause alterations in the globin protein, resulting in structurally altered hemoglobin (variant hemoglobin), such as hemoglobin S, which causes sickle cell, or a decrease in globin chain production (quantitative change) (thalassemias). In thalassemia, the reduced production of one of the globin chains upsets the balance of alpha to beta chains and causes abnormal hemoglobin to form (alpha thalassemia) or causes an increase of minor hemoglobin components, such as Hb A2 or Hb F (beta thalassemia)
Several hundred abnormal forms of hemoglobin (variants) have been identified, but only a few are common and clinically significant.
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Specimen type / Specimen volume / Specimen container
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Whole blood.
Container/Tube: EDTA.
Specimen Volume: 2ml.
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Collection instructions / Special Precautions / Timing of collection
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Relevant clinical information to be provided
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Patient/family history of hemoglobinopathies, recent blood transfusion, ethnicity, geographical origin/Nationality, hyperbilirubinemia, diabetes.
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Storage and transport instructions
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Ambient/Refrigerated (specimens are stable for 24 hours if stored at room temperature and 48 hours if stored at 2-8°C).
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Specimen Rejection Criteria
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Insufficient quantity of blood (<1ml in macrotubes & <0.5ml in microtubes).
Errors in patient identification.
Delayed (old) specimen.
Clotted specimen/hemolyzed sample.
Wrong/unlabeled collection container.
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Biological reference intervals and clinical decision values
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Normal range for Adult:
Hb A 95.8- 98.0%
Hb A2: 2.0- 3.3%
Hb F: 0.0-0.9%
Paediatric reference ranges will be released with the patient’s report according to the age.
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Factors affecting test performance and result interpretation
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Recent blood transfusion may give false results.
Patient's age is important for result interpretation.
Hyperbilirubinemia
Diabetes
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Turnaround time / Days and times test performed / Specimen retention time
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7 working days
Test is performed daily
Specimen is retained for 7 Days at 2 - 8 °C
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