A nurse is assessing a client with iron deficiency. Which assessment finding should the nurse recognize as koilonychia?

Choice A reason: Firm and slightly tender nail bases may indicate localized trauma or inflammation but are not characteristic of koilonychia. This finding does not reflect the structural changes seen in iron deficiency anemia. Choice B reason: Cyanotic nail bases are associated with poor oxygenation or circulatory problems, such as in respiratory or cardiac conditions. This is unrelated to iron deficiency anemia and does not describe koilonychia. Choice C reason: Curved nails with a concave profile, often referred to as "spoon-shaped nails," are the hallmark of koilonychia. This condition is strongly linked to iron deficiency anemia and results from structural weakening of the nail plate due to impaired hemoglobin synthesis. Choice D reason: Nail bases with an angle of 180 degrees or greater describe clubbing, which is associated with chronic hypoxia, lung disease, or cardiac conditions. This is distinct from koilonychia and not related to iron deficiency anemia.