The ABCs of a CBC

On medical TV shows, a patient is rushed into the ER and the doctor immediately orders a “CBC.” After watching more episodes of “House” and “Grey’s Anatomy” than I care to admit, I realized I had little idea of what this routine blood test was. So I did some homework and talked with some doctors.

“CBC” stands for a complete blood count test, and it’s used to help diagnose and monitor a myriad of conditions. Your doctor may order this test as part of your regular checkup or if you’re experiencing symptoms such as fever, fatigue, weight loss, bruising or bleeding, which can indicate serious health issues. The test can also be a helpful diagnostic tool if you have allergies or believe you’ve been exposed to high levels of lead or other toxins.

A CBC test provides important information about the kinds and numbers of cells in your blood—especially red blood cells, white blood cells and platelets. Red blood cells are responsible for carrying oxygen from the lungs to the rest of the body, and carrying carbon dioxide to the lungs. White blood cells help the body fight off infection. Platelets are small blood cells that are important for blood clotting.

An increase or decrease in the numbers of these different types of blood cells can help identify infection, an allergic or toxic reaction to certain medications or chemicals and many other medical conditions. For example, a significant increase in white blood cells may indicate an infection. A reduced red blood cell count, also known as anemia, may indicate health issues. A low platelet count may explain the reason behind excessive bleeding or bruising.

The CBC test helps monitor a patient’s response to medications or special treatment, such as chemotherapy and radiation therapy. CBCs can also measure if you have been exposed to lead or other toxins.

So whether you’re in the ER or simply watching a TV drama about one, now you know why they so often start with a CBC.