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SDEX
9180
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.
Useful For: Monitoring patients with sickling disorders who have received hydroxyurea or transfusion
therapy
Interpretation: Optimal levels of hemoglobin S and hemoglobin F are patient specific and depend on
a number of factors including response to therapy.
Reference Values:
HEMOGLOBIN F
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%
> or =24 months: 0.0-0.9%
HEMOGLOBIN S
All ages: 0.0%
Clinical References: 1. The Management of Sickle Cell Disease. 4th 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
Hemoglobin S, Screen, Blood
Clinical Information: Homozygous hemoglobin S (sickle cell disease) is a serious chronic hemolytic
anemia most commonly found in those of African or Middle Eastern descent. Hemoglobin S is freely
soluble when fully oxygenated; when oxygen is removed, polymerization of the abnormal hemoglobin
occurs, forming tactoids that are rigid and deformed cells. This leads to sickling of the cells, hemolysis,
and many other complications. Heterozygous hemoglobin S (sickle cell trait) is the most common
hemoglobinopathy in the United States. This condition is present in about 8% of African Americans.
Usually, hemoglobin S trait exhibits no clinical or hematological effects. A small fraction of people with
sickle cell trait have recurrent hematuria.
Useful For: Screening for hemoglobin S (sickle cell trait)
Interpretation: A positive result should be followed by hemoglobin electrophoresis to confirm the
presence and concentration of hemoglobin S.
Reference Values:
Negative
Precautions: The procedure does not distinguish hemoglobin S trait from homozygous sickle cell disease
nor any of the following combinations: S/C, S/D, S/G, S/E, S/thalassemia, S/O-Arab, S/New York and
C-Georgetown trait (Hb C-Harlem).
Clinical References: Fairbanks VF, Klee GG: Biochemical Aspects of Hematology. In Tietz
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