Causes of high hemoglobin include increase in red blood cell production, smoking, certain medications and bone marrow disease. Some conditions, such as heart failure, liver cancer, kidney cancer and dehydration can also lead to high hemoglobin count, as stated by Mayo Clinic.
A high hemoglobin count does not mean that a person has high amount of red blood cells, as stated by Mayo Clinic. A person with red blood cells falling below the normal count can also have high hemoglobin count. This condition is usually rare, and it is usually detected during a test for a particular disease or condition.