Blister cells on the peripheral blood smear of a newborn infant are most consistent with which condition?

• A. G6PD deficiency
• B. Decreased cell membrane volume
• C. Normal in the newborn period
• D. Sickle cell disease

Answer: (A)

Blister cells reflect oxidative damage to red blood cells. In G6PD deficiency, the red cell’s ability to generate NADPH via the pentose phosphate pathway is impaired, so reduced glutathione leaves hemoglobin vulnerable to oxidative stress from infections, certain drugs, or other triggers. The oxidative injury leads to membrane damage and removal of Heinz bodies by the spleen, producing fragmented or blistered areas on the cell—hence blister cells seen on the smear. This pattern is a classic hint of oxidative hemolysis due to G6PD deficiency, which can present in newborns with hemolysis or jaundice.

Other options don’t fit this smear finding well. A normal newborn smear wouldn’t show blister cells, and sickle cell disease typically shows sickled cells rather than blistered membranes. Describing something as “decreased cell membrane volume” isn’t a standard explanation for this smear pattern.