A nurse in a provider's office is caring for a client. For each client's finding, click to specify if the assessment finding is consistent with sickle cell disease, iron deficiency anemia, and/or pernicious anemia. Each finding may support more than 1 disease process.

All three conditions, sickle cell disease, iron deficiency anemia, and pernicious anemia, can cause reduced oxygen-carrying capacity leading to fatigue, but they differ in underlying pathology—hemolytic (sickle cell), nutritional iron deficiency, and vitamin B12 deficiency affecting DNA synthesis. Laboratory markers such as ferritin and vitamin B12 levels are key diagnostic indicators, while clinical signs like fatigue and orthostatic hypotension reflect decreased tissue oxygenation. Understanding these distinctions is essential for accurate interpretation of hematologic findings. • Fatigue: Fatigue is a common symptom in all forms of anemia due to decreased oxygen delivery to tissues. In sickle cell disease, hemolysis reduces RBC lifespan. In iron deficiency anemia, reduced hemoglobin synthesis impairs oxygen transport. In pernicious anemia, impaired DNA synthesis leads to ineffective erythropoiesis. All result in reduced oxygenation and generalized fatigue. • Ferritin level: Ferritin reflects stored iron levels in the body and is typically low in iron deficiency anemia. It indicates depleted iron reserves, which directly affects hemoglobin production. In sickle cell disease and pernicious anemia, ferritin is not primarily affected. Therefore, low ferritin is most consistent with iron deficiency anemia. • Orthostatic hypotension: Orthostatic hypotension can occur in all anemia types due to reduced oxygen delivery and decreased circulating red blood cell mass. This leads to compensatory tachycardia and impaired vascular response when changing positions. In sickle cell disease, vaso-occlusion and chronic anemia contribute; in iron deficiency and pernicious anemia, reduced oxygen-carrying capacity is the main cause. Thus, it is common to all three conditions. • Vitamin B12 level: Low vitamin B12 levels are diagnostic of pernicious anemia, which results from impaired absorption due to intrinsic factor deficiency. Vitamin B12 is essential for DNA synthesis and RBC maturation. Deficiency leads to megaloblastic anemia and neurologic symptoms. This marker is not associated with sickle cell disease or iron deficiency anemia.