answered Nov 28, 2010 at 09:40AM
The color of mucus does not help much in determining if there is a sinus infection or not. A sinus infection is diagnosed clinically based on symptoms such as fever, tenderness over the sinuses, and the presence of fluid in the sinuses (which can be determined through transillumination of the sinuses). Even then, most cases (>80%) are caused by viruses and will go away on their own with symptomatic treatment.