Two units of low-titer O whole blood in a 72-year-old male with a lower GI bleed; after two units, the repeat Hgb and Hct would be approximately?

• A. Hgb 7.5 g/dL, Hct 31
• B. Hgb 7.8 g/dL, Hct 32
• C. Hgb 8.2 g/dL, Hct 30
• D. Hgb 8.0 g/dL, Hct 34

Answer: (B)

Transfusion of red-cell–containing products raises the blood’s oxygen-carrying capacity by a predictable amount. In adults, each unit typically increases hemoglobin by about 1 g/dL and hematocrit by about 3 percentage points. With two units, you’d expect roughly a +2 g/dL rise in hemoglobin and about +6 percentage points in hematocrit. In a patient with an ongoing lower GI bleed, pretransfusion values are usually low, so the posttransfusion values would land roughly in the range of hemoglobin around 7.5–8 g/dL and hematocrit around 30–33%. The combination of approximately 7.8 g/dL and 32% best fits this expected rise.