A Bloodtime Story

Robert Gagliano, M.D.

It isn’t by chance that during an annual health examination your physician will ask you to have a blood test. Blood is your body’s main transport system. It carries raw materials and finished chemical products to-and-from your organs, and carries wastes for disposal. Blood carries so many essential substances throughout your body—a blood test is a first step in monitoring how healthy you are.

A few important and amazing items to note about your blood:

- Blood makes up about seven percent of your body weight.
- The average size adult has 10-12 pints of blood that circulate through 60,000 miles of blood vessels!
- Your heart pumps the equivalent of 400 gallons of blood each day
- Sugar/glucose circulates to provide energy
- Red blood cells (RBCs) carry needed oxygen to your tissues
- Half of your blood is made up of red cells and the remaining half is the liquid portion of blood called plasma.
- Plasma is 95 percent water. Besides containing antibodies to help prevent and fight infection, plasma also has blood-clotting proteins called factors
- Plasma carries vitamins, minerals, carbohydrates, proteins, fats, hormones and enzymes.

All the blood cells in your body are made inside your bones in the marrow. Red blood cells have an iron-containing pigment called hemoglobin that gives the cells a red color. They pick up oxygen in the lungs and carry carbon dioxide away. The normal RBC lives about 120 days. One percent, about half an ounce, of RBCs must be replaced each day. Half of your RBCs are replaced weekly!

Blood also contains two different types of white blood cells (WBC), neutrophils and lymphocytes. Neutrophils are able to leave the blood and move into tissues to fight bacterial and fungal infections. They only live one or two days.

Lymphocytes are part of your immune system. About one billion new lymphocytes are made each day. They battle viruses and parasites and help fight cancer cells.

Platelets also are a blood component. Platelets are fragments of cells which help stop bleeding when blood vessels are injured. They do this by clumping together, plugging the hole/injury, and starting the clotting process. They survive about 10 days, and ten percent of your platelets are replaced each day.

There are hundreds of diseases and medications which can raise or lower one or more of the three main blood cell components. These diseases and medications can cause these changes in the components by affecting bone marrow production. They also can cause change by increasing component destruction during circulation or in the spleen. Such changes in blood cell levels can result in: anemia (low RBCs), polycythemia (high RBCs), high risk of infections (low WBC), bleeding (low platelets), or clotting (high platelets). 

Acute and chronic blood cell cancers like leukemia affect either neutrophils or lymphocytes, causing a high WBC.

Diseases and medications also can change the function of one or more cell types without changing cell numbers. Aspirin, for example, impairs platelet function so can be used as a “blood thinner” to help prevent heart attacks.

Your blood stays liquid in your vessels because there is a delicate and perfect balance between bleeding and clotting (thrombosis). Blood constantly is forming new clots and breaking them down at the same time to maintain a liquid state. Plasma contains dozens of clotting and anti-clotting proteins/factors made in your liver and blood vessels. These factors act as enzymes, triggering a step-by-step chain reaction to form (or break down) clots. Over supply, decreased activity, inhibition or deficiency of even one of these factors can result in a severe bleeding or clotting problem. Rarely, a severe bleeding problem can be hereditary like Hemophilia A, or a severe clotting problem like Factor V Leiden mutation.

Blood is a diverse and fascinating subject. There is a special branch of medicine concerned with its nature, function and diseases: Hematology. You often will see this specialty in connection with the study of Oncology/Cancer.

Finally, it’s obvious how valuable your blood is to your well-being, and to others, so it’s okay to periodically give some of it up! Here are some interesting facts about blood donation.

- There are four main blood types: A, B, AB, and O. Type
- O is most common, about 50 percent of the population is Type O
- Donated blood will be separated into four parts: red cells, platelets, plasma and clotting factors – which can be administered individually, basically quadrupling your donation
- Eight million people donate blood each year in the USA
- Five million people receive 14 million transfusions annually in the USA

Let’s all pitch in and help someone in need “fill their tank” when it gets too low. Be a blood donor…its only one pint, about two cups, and remember—you’ve got 10-12 pints.

Robert Gagliano, M.D., has more than 30 years experience in treating cancer patients. He has participated in many clinical trials and studies. He is board certified in oncology and internal medicine.