This photograph of a peripheral blood smear from an 18-year-old North African woman with anemia reveals sickle cells.

• Target cells are not conspicuous. This shifts the diagnostic evidence away from HbSC disease.
• Cells tagged by arrows are variants of sickle cells. These may appear when multiple abnormal hemoglobin combinations are responsible for the clinical problem.
• The cell marked by the single arrow is an envelope formed not only in HbS disease but in HbC disease as well.
• Two arrows tag a blister cell, which, when seen in several fields, should prompt a hemoglobin electrophoresis to determine the presence of an undiagnosed hemoglobinopathy.
• Blister cells with fuzzy edged pseudo-vacuoles (see photo) are to be distinguished from the pseudo-vacuoles (blister)with razor sharp edges suggesting a microangiopathic state.