Which statement about cyanosis as an indicator of hypoxemia is true?

• A. Cyanosis Is Present Only with Severe Anemia
• B. Cyanosis Occurs Only When Desaturated Hb Exceeds 15 g/dL
• C. Infants with Anemia May Be Hypoxemic but Never Demonstrate Cyanosis
• D. Cyanosis Is Never Related to Hemoglobin Status

Answer: (C)

Cyanosis requires enough deoxygenated hemoglobin in the circulating blood to give a blue tint to the skin and mucous membranes. The amount of deoxygenated Hb needed is linked to how much total hemoglobin is present. In infants with anemia, total Hb is reduced, so even if oxygen saturation is low (hypoxemia), the absolute quantity of deoxygenated Hb may not reach the level needed to produce visible cyanosis. That means hypoxemia can be present without cyanosis in anemic infants, which is why this statement is the best choice among the options.

Cyanosis is not exclusive to severe anemia; it can occur with normal Hb if saturation is sufficiently low. There isn’t a fixed desaturation threshold like a specific g/dL value that universally triggers cyanosis. And in any case, hemoglobin status clearly affects whether cyanosis is observed, so saying cyanosis is never related to Hb status is incorrect.