Final answer:
A bluish tinge in nails and lips suggests the medical condition cyanosis, which indicates poor circulation or low oxygenation of the blood.
Step-by-step explanation:
A bluish tinge in the nails and lips is an indication of poor circulation or low oxygen in the blood, a condition known as cyanosis. This condition arises when there is insufficient oxygen coupled with the presence of dark red deoxyhemoglobin in the blood, giving skin and mucous membranes a blue color. In particular, healthcare providers look at the color of the fingernail beds as this is a quick indicator of oxygen saturation, and to see if blood flow to the extremities is adequate, a blanch test may be performed.