A nurse is assessing a 65-year-old male client with iron-deficiency anemia. Which laboratory finding would the nurse expect to see?

Increased TIBC is expected in iron-deficiency anemia due to low iron stores. Other options are not characteristic findings.

Understanding Iron-Deficiency Anemia (IDA) Laboratory Findings

When a nurse assesses a client for iron-deficiency anemia, understanding the physiological basis of laboratory markers is essential. In IDA, the body's iron stores are depleted, leading to a predictable pattern of changes in serum iron, ferritin, and the body's iron-carrying capacity.

The correct finding is an increased total iron-binding capacity (TIBC). TIBC is an indirect measure of the protein transferrin, which transports iron in the blood. In a state of iron depletion, the liver compensates by producing more transferrin in an attempt to maximize the capture and transport of any available iron. This physiological upregulation results in a high TIBC, a hallmark of uncomplicated iron deficiency ^[1].

Let's analyze why the other options are incorrect and how they relate to the underlying pathophysiology.

Analysis of Incorrect Options

1. Elevated serum ferritin is incorrect. Serum ferritin reflects the body's total iron stores. In true iron-deficiency anemia, these stores are depleted, leading to a low serum ferritin level. An elevated ferritin would suggest iron overload or an inflammatory state, as ferritin is also an acute-phase reactant. The diagnostic challenge in patients with chronic inflammation or cirrhosis, as noted in the literature, is that ferritin can be falsely normal or elevated despite concurrent iron deficiency, making markers like TIBC more reliable in such contexts ^[1].
3. Normal hemoglobin with low hematocrit is incorrect. Iron deficiency impairs heme synthesis, which is the oxygen-carrying component of hemoglobin. This leads to a proportional decrease in both hemoglobin and hematocrit (the percentage of red blood cells in whole blood). The anemia is typically normocytic early on but becomes microcytic and hypochromic as the deficiency progresses. A finding of normal hemoglobin would not be consistent with the diagnosis of anemia.
4. Decreased red blood cell count with macrocytosis is incorrect. IDA is characterized by a defect in hemoglobin production, which leads to extra cell divisions in the bone marrow and the production of smaller-than-normal red blood cells (microcytosis). Macrocytosis, or large red blood cells, is typically associated with megaloblastic anemias caused by vitamin B12 or folate deficiency, not iron deficiency. The study on pediatric mixed anemias highlights that a combined deficiency of iron and vitamin B12 can present with a confusing blood picture, but for pure IDA, microcytosis is the expected finding .

Clinical Reasoning and Diagnostic Approach

The nurse's assessment integrates these lab values to form a clinical picture. In a 65-year-old male, the presence of IDA is a critical finding that requires further investigation to rule out gastrointestinal blood loss, as this is the most common cause of IDA in older adults. The diagnostic yield of procedures like gastroscopy is evaluated precisely for this reason—to identify clinically significant findings, including malignancies, that may be the underlying source of chronic blood loss . The laboratory pattern of low serum iron, low ferritin, and high TIBC confirms the diagnosis of iron deficiency and prompts the necessary next steps in the diagnostic workup to determine the etiology of the iron loss.