My leg turns redish purple while sitting or standing, but fine while lying. tingles too. blood test says no dvt or clot. what else causes this?

Raynauds: I see color changes frequently in the hands and feet which go from white to blue to red. These changes are very common in a condition called raynauds. Raynauds can exist alone or with other conditions. It is usually also associated with anxiety, caffeine and nicotine as well as cold sensitivity. There are other conditions that can cause color changes such as genetics and fair skin.

Likely stasis: There are signs of congestion. If pulses and inflow are good-normal. Then cyanosis edema are signs of congestion. Can be from heart failure, tricuspid valve, or more likely venous insufficiency without a current clot. On the left occasionally the vein is compressed and can lead to congestion. See a vascular surgeon and get an on site opinion and followup.