Hemoglobin (Hgb)

This protein, when fully oxygenated, is characteristically bright red. Whenever it loses a significant amount of its' oxygen, it turns a dark blue color. It takes about 6 grams of desaturated hemoglobin to cause a noticeable change in color.

Increased in the Presence of:

• Hemoconcentration
• COPD (chronic obstructive pulmonary disease)
• CHF (congestive heart failure)
• Smokers
• Pre-eclampsia

Decreased in the Presence of:

• Anemia
• Hyperthyroidism
• Chronic liver disease
• Hemorrhage
• Hemolysis:
  • Transfusion reaction
  • Drug/chemical reaction
  • Infection
  • Burns
  • Mechanical disruption (artificial heart valves)
• Systemic Disease
  • Cancer
  • Lupus
  • Sardoidosis

Special Considerations

• Carbon monoxide binds to the hemoglobin, rendering it incapable of carrying oxygen, but clinically causes the victims' blood to be bright, cherry-red
• Smokers typically have elevated hemoglobin levels in response to chronic, low-grade carbon monoxide poisoning and other mild respiratory ailments. Because of the carbon monoxide binding, they may still be functionally anemic, even though their hemoglobin levels look good.
• Adaptation to high altitudes includes moderate elevation of hemoglobin.
• During the initial phases of an acute hemorrhage, the hemoglobin levels generally doesn't change very much. Later, as extracellular fluid is mobilized and IV fluids are incorporated, there is a dilutional effect that will lead to a reduced hemoglobin level. This fall in hemoglobin may take several hours to develop.

Normal Values*

*These are general values taken from a variety of sources. The actual normal values may vary from lab to lab and from one type of testing protocol to another.