All Medical Procedures

A hemoglobin test measures the amount of hemoglobin in your blood.

Hemoglobin is a protein in your red blood cells that carries oxygen to your body's organs and tissues and transports carbon dioxide from your organs and tissues back to your lungs.

If a hemoglobin test reveals that your hemoglobin level is lower than normal, it means you have a low red blood cell count (anemia). Anemia can have many different causes, including vitamin deficiencies, bleeding and chronic diseases.

If a hemoglobin test shows a higher than normal level, there are several potential causes — the blood disorder polycythemia vera, living at a high altitude, smoking, dehydration, burns and excessive vomiting.

A prothrombin time test measures how quickly your blood clots. Sometimes called a pro time test or PT test, a prothrombin time test uses a sample of your blood.

Prothrombin is a protein produced by your liver that helps your blood to clot. When you bleed, a series of chemicals (clotting factors) activate in a stepwise fashion. The end result is a clot which stops the bleeding. One step in the process is prothrombin turning into another protein called thrombin. The prothrombin time test measures how well the clotting process works and how long it takes to occur.