This is only a concern if you have frequent headaches, dizziness, skin rashes, red flush face which are signs and symptoms of polycythemia vera.
Hello~This can happen at times for no apparent reason. Also, some labs have different values as to what the "normals" should be. Also, mild dehydration can cause an elevation in the hemoglobin, I suggest drinking lots of water before your next blood draw, this might be the only issue. I would discuss your concerns with the doctor.