What exactly does it mean when you have high hemoglobin levels in your blood?

It requires consulta. A consultation with a hematologist may be useful if you have high hemoglobin. There is a rare medical condition called polycythemia vera but it also has some changes in white cell counts. It requires a specialist to confirm the diagnosis as hemoglobin can be high due to several different reasons. These can be sorted out by visiting a hematologist.