Cyanosis is the change of body tissue color to a bluish-purple hue as a result of having decreased amounts of oxygen bound to the hemoglobin in the red blood cells of the capillary bed. Body tissues that reflect cyanosis are usually in locations where the skin is thinner, including the mucous membranes, lips, nail beds, and ear lobes. Some medications containing amiodarone or silver, Mongolian spots, large birth marks, and the consumption of food products with blue or purple dyes can also result in the bluish skin tissue discoloration and may be mistaken for cyanosis.Cyanosis is further classified into central cyanosis vs. peripheral cyanosis. Pathophysiology
The mechanism behind cyanosis is different depending on whether it is central or peripheral. Central cyanosis
Central cyanosis is caused by a decrease in arterial oxygen saturation (SaO2) and begins to show once the concentration of deoxyhemoglobin in the blood reaches a concentration of ≥ 5.0 g/dL (≥ 3.1 mmol/L or oxygen saturation of ≤ 85 %). Causes of central cyanosis are discussed below. Peripheral cyanosis
Peripheral cyanosis happens when there is increased concentration of deoxyhemoglobin on the venous side of the peripheral circulation. In other words, cyanosis is dependent on the concentration of deoxyhemoglobin. Patients with severe anemia may appear normal despite higher than normal concentrations of deoxyhemoglobin. On the other hand, patients with increased amounts of red blood cells (e.g. polycythemia vera) can appear cyanotic even with lower concentrations of deoxyhemoglobin.
In extravascular hemolysis, red blood cells are phagocytized by macrophages in the spleen and liver.Abnormal value of hemoglobin does not necessarily indicate a medical problem needing treatment. Diet, activity level, medications, a womens menstrual cycle, and other considerations can affect the results. Additionally to these, one may have higher than normal hemoglobin if he/she lives in a high altitude area. Causes
There are other causes besides what happens within the body in the blood cells. Other factors that can cause an excess amount of hemoglobin are:

Smoking (which may result in low blood oxygen levels)
Higher altitudes where your red blood cell production naturally increases to compensate for the lower oxygen supply thereSpecific disorders or other factors that may cause a high hemoglobin count include:

Lung disease
Heart disease
COPD (chronic obstructive pulmonary disease)
Dehydration
Emphysema
Heart failure
Kidney cancer
Liver cancer
Other types of heart disease
Other types of lung disease
Polycythemia vera, a disorder in which your body makes too many red blood cells. It can cause headaches, fatigue, and shortness of breath. Diagnosis
Normal hemoglobin levels
Normal hemoglobin levels correlate with the persons age and sex. Levels can vary between different testing systems and under their doctors consultation. A hemoglobin test measures the amount of hemoglobin in your blood. If a hemoglobin tests shows that a persons levels are below normal, it means they have a low red blood cell count, which is known as anemia. If the test shows higher levels than normal, it means they have hemoglobinemia.The normal range for hemoglobin is:

For men, 13.5 to 17.5 grams per deciliter.