Why are my fingernails blue? they're not cold at all, just blue. are blue fingernails always a sign of a heart problem? pict >> http://goo.gl/hsf6w

Cyanosis: Cyanosis often represents a low oxygen level, representing a cardiac or pulmonary problem. It merits the evaluation by a cardiologist or a pulmonologist.

Not uncommon: If they are always blue it can be a sign of cyanotic heart disease. If they are sometimes blue it can be a condition called raynaud's disease.Here is a reference: http://www.Nlm.Nih.Gov/medlineplus/raynaudsdisease.Html.