hemoglobin electrophoresis (Hgb electrophoresis)
المؤلف:
Kathleen Deska Pagana, Timothy J. Pagana, Theresa Noel Pagana.
المصدر:
Mosbys diagnostic and laboratory test reference
الجزء والصفحة:
15th edition , p492-494
2025-12-20
36
Type of test Blood
Normal findings
Adult/elderly: percentage of total Hgb Hgb
A1 : 95%-98%
Hgb A2 : 2%-3%
Hgb F: 0.8%-2%
Hgb S: 0%
Hgb C: 0%
Hgb E: 0%
Children: Hgb F
Newborn: 50%-80%
< 6 months: < 8%
> 6 months: 1%-2%
Test explanation and related physiology
Hgb electrophoresis is a test that identifies and quantifies normal and abnormal forms of Hgb (hemoglobinopathies). Although many different forms of Hgb have been described, the more common types are A1 , A2 , F, S, E, and C. Each major Hgb type is electrically charged to varying degrees. Each electrophoretic band can be quantitated as a percentage of the total Hgb, indicating the severity of any recognized abnormality.
The form Hgb A1 constitutes the major component of Hgb in the normal RBC. Hgb A2 is only a minor component (2%-3%) of the normal Hgb total. Hgb F is the major Hgb component in a fetus but normally exists in only minimal quantities in a normal adult. Levels of Hgb F greater than 2% in patients older than age 3 years are considered abnormal. Hgb F is able to transport oxy gen when only small amounts of oxygen are available (as in fetal life). In patients requiring compensation for prolonged chronic hypoxia (as in congenital cardiac abnormalities), Hgb F may be found in increased levels to assist in the transport of the available oxygen.
Hgb S and Hgb C are abnormal forms of Hgb that occur pre dominantly in African Americans. Hgb E occurs predominantly in Southeast Asians. The Hgb contents of some common disorders affecting Hgb, as determined by electrophoresis, are indicated in Table 1. Hgb E is produced less efficiently by RBC precursors; if there is an increased Hgb E content in the RBCs, those cells will have a low mean corpuscular volume (MCV).
Table1. Hemoglobin (Hgb) contents of some common hemoglobinopathies
Quantifying abnormal hemoglobins is helpful in determining the zygosity of a familial hemoglobinopathy. Furthermore, quantification of abnormal Hgb proteins provides a method of monitoring treatments designed to increase more effective Hgb variants and decrease abnormal variants.
Interfering factors
• Blood transfusions within the previous 12 weeks may alter test results.
• Glycosylated Hgb can blur the peak of Hgb F and cause falsely low levels of Hgb F.
Procedure and patient care
• See inside front cover for Routine Blood Testing.
• Fasting: no
• Blood tube commonly used: lavender
Abnormal findings
- Sickle cell disease
- Sickle cell trait
- Hgb C disease
- Hgb H disease
- Thalassemia major
- Thalassemia minor
- Hgb E disease
الاكثر قراءة في التحليلات المرضية
اخر الاخبار
اخبار العتبة العباسية المقدسة
