Skip to main content

Typical Laboratory Findings in Sickle Cell Disease


Genotype Hb* (g/dL) HbS* (%) HbA* (%)  HbA2* (%) HbF *(%) HbC* (%)
SS 6–9 >90 0 <3.5 <10 0
0-thalassemia 7–9 >80 0 >3.5 <20 0
+-thalassemia 9–12 >60 10–30 >3.5 <20 0
SC 9–14 50 0 <3.5 ≤1.0 45

*Definitions for abbreviations are as follows: Hb = hemoglobin; HbS = sickle hemoglobin; HbA = normal adult hemoglobin; HbA2 = minor variant of adult hemoglobin; HbF = fetal hemoglobin; HbC = hemoglobin variant that causes manifestations of SCD when paired with HbS

The hemoglobin values in this exhibit apply in the absence of a blood transfusion in the last 4 months, are not absolute, and are applicable to adults and children only (not newborns).

Reference: Expert Panel Report. (2014). Evidence-Based Management of Sickle Cell Disease. National Institutes of Health. Retrieved from

These guidelines do not establish a standard of care to be followed in every case. It is recognized that each case is different and those individuals involved in providing health care are expected to use their judgment in determining what is in the best interests of the patient based on the circumstances existing at the time. It is impossible to anticipate all possible situations that may exist and to prepare guidelines for each. Accordingly these guidelines should guide care with the understanding that departures from them may be required at times.