What is the best definition of anemia?

a. Red cell count 10% lower than the patient's baseline
b. Decreased hemoglobin, hematocrit, and red cell count compared with healthy people in the same demographic group
c. Hemoglobin below 12 g/dL
d. Any clinical condition resulting in shortness of breath, increased heart rate, pallor, and fatigue

ANS: B
The best definition of anemia is a decreased hemoglobin, hematocrit, and red cell count compared with healthy people in the same demographic group. Ideally it would be a decrease below the patient's normal baseline, but that is often not known. Reference ages for hemoglobin vary dependent on sex, age, and environmental factors (e.g., altitude); for this reason a single cutoff such as 12 g/dL cannot be used. The symptoms for anemia are nonspecific, although they certainly help support the diagnosis.