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Test ID HGBCE Hemoglobin Variant, A2 and F Quantitation, Blood

Useful For

Monitoring patients with sickling disorders who have received hydroxyurea or transfusion therapy

Method Name

Capillary Electrophoresis

Reporting Name

Hb Variant, A2 and F Quantitation,B

Specimen Type

Whole Blood EDTA

Advisory Information

This test is intended for monitoring purposes, such as the increase in hemoglobin F (Hb F) after therapy, or the levels of hemoglobin variants after transfusion. The HPFH / Hemoglobin F, Red Cell Distribution, Blood test is a flow cytometry assay that determines the distribution of Hb F within red blood cells.


If the patient has never been appropriately studied, hemoglobin electrophoresis is necessary (see HBELC / Hemoglobin Electrophoresis Cascade, Blood).

Necessary Information


Specimen Required


Preferred: Lavender top (EDTA)

Acceptable: ACD, heparin

Specimen Volume: 4 mL

Collection Instructions:

1. Submit fresh specimen.

2. Do not transfer blood to other containers.

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole Blood EDTA Refrigerated 10 days

Clinical Information

The treatment of red blood cell sickling disorders may involve many therapeutic modalities. Two of the most important and beneficial are treatment with hydroxyurea and chronic transfusion therapy. Hydroxyurea causes elevation of hemoglobin F (Hb F) levels, and transfusion serves to lower the percentage of hemoglobin S (Hb S). Both of these therapeutic modalities act to lessen the number and severity of sickling crises. Thus, periodic monitoring of Hb F and Hb S levels are needed to guide further therapy.

Reference Values


1-30 days: 5.9-77.2%

1-2 months: 7.9-92.4%

3-5 months: 54.7-97.1%

6-8 months: 80.0-98.0%

9-12 months: 86.2-98.0%

13-17 months: 88.8-98.0%

18-23 months: 90.4-98.0%

≥24 months: 95.8-98.0%



1-30 days: 0.0-2.1%

1-2 months: 0.0-2.6%

3-5 months: 1.3-3.1%

≥6 months: 2.0-3.3%



1-30 days: 22.8-92.0%

1-2 months: 7.6-89.8%

3-5 months: 1.6-42.2%

6-8 months: 0.0-16.7%

9-12 months: 0.0-10.5%

13-17 months: 0.0-7.9%

18-23 months: 0.0-6.3%

≥24 months: 0.0-0.9%











Clinically, optimal levels of hemoglobin S (Hb S) and hemoglobin F (Hb F) are patient specific and depend on a number of factors including response to therapy. This test will be performed by capillary electrophoresis and any variant present will be reported as their zone only, including Hb S. No confirmatory functional study such as sickle solubility will be performed. Information reported: Percentages of hemoglobin A (Hb A), hemoglobin A2 (Hb A2), Hb F and any variant present. Variants will be reported as zones and are not specific, even if present in Z5 (Zone S). If the identity of the variant has not been previously confirmed, diagnostic hemoglobin electrophoresis is necessary (see HBELC / Hemoglobin Electrophoresis Cascade, Blood).

Clinical Reference

1. The Management of Sickle Cell Disease. Fourth edition. Bethesda, MD: National Institutes of Health. National Heart, Lung, and Body Institute, 2002

2. Rosse WF, Telen M, Ware R: Transfusion Support for Patients with Sickle Cell Disease. Bethesda, MD: American Association of Blood Banks 1998

3. Ferster A, Tahriri P, Vermylen C, et al: Five years of experience with hydroxyurea in children and young adults with sickle cell disease. Blood 2001;97:3268-3632

4. Charache S, Terrin ML, Moore RD, et al: Effect of hydroxyurea on the frequency of painful crises in sickle cell anemia. Investigators of the Multicenter Study of Hydroxyurea in Sickle Cell Anemia. N Engl J Med 1995;332:1317-1322

5. Sebia CapillaryS Manual: 2014(06) Available at

6. Keren DF, Shalhoub R, Gulbranson R, et al: Expression of hemoglobin variant migration by capillary electrophoresis relative to hemoglobin A2 improves precision. Am J Clin Pathol 2012 Apr;137(4):660-664

Day(s) and Time(s) Performed

Monday through Saturday; 7 a.m., 1 p.m.

Analytic Time

Same day/1 day

Test Classification

This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

83020-Quantitation by Electrophoresis

LOINC Code Information

Test ID Test Order Name Order LOINC Value
HGBCE Hb Variant, A2 and F Quantitation,B 43113-0


Result ID Test Result Name Result LOINC Value
41927 Hb A 20572-4
41928 Hb F 4576-5
41929 Hb A2 4551-8
41930 Variant 1 24469-9
41931 Variant 2 24469-9
41932 Variant 3 24469-9
41933 HGBCE Interpretation 78748-1


1. Thalassemia/Hemoglobinopathy Patient Information (T358) in Special Instructions

2. If not ordering electronically, complete, print, and send a Benign Hematology Test Request Form (T755) with the specimen.

Testing Algorithm

See Benign Hematology Evaluation Comparison in Special Instructions.