Which sign indicates low oxygenation and presents as a blue tint to the skin and mucous membranes?

Which sign indicates low oxygenation and presents as a blue tint to the skin and mucous membranes?

• A. Pallor
• B. Jaundice
• C. Erythema
• D. Cyanosis

Answer: (D)

When oxygen levels are low in the blood, more hemoglobin is deoxygenated and has a bluish hue. This makes tissues especially around the lips, tongue, and nail beds look blue or dusky—a sign known as cyanosis. It directly indicates hypoxemia and the need for rapid assessment and potential intervention. Other signs like pallor describe pale skin from reduced blood flow or anemia, jaundice is yellow from bilirubin buildup, and erythema is redness from increased blood flow or irritation. Cyanosis is the best clue among these for low oxygenation.

When oxygen levels are low in the blood, more hemoglobin is deoxygenated and has a bluish hue. This makes tissues especially around the lips, tongue, and nail beds look blue or dusky—a sign known as cyanosis. It directly indicates hypoxemia and the need for rapid assessment and potential intervention. Other signs like pallor describe pale skin from reduced blood flow or anemia, jaundice is yellow from bilirubin buildup, and erythema is redness from increased blood flow or irritation. Cyanosis is the best clue among these for low oxygenation.