Complete Blood Count (CBC)

What is this test? The complete blood count (CBC) is a routine blood test that measures the different cells in your blood, including red blood cells, white blood cells, and platelets, to help your doctor evaluate your overall health and screen for many common conditions.

The Base Excess test measures the amount of excess base (alkaline substances) in your blood. It is calculated from a sample of mixed venous blood, which is blood that has traveled through the body and is returning to the heart from both the upper and lower parts of the body. This test helps doctors understand how well your body is maintaining the acid-base balance in your blood.

How is the test performed? A trained health care professional will clean your skin, wrap a band around your upper arm, and draw a small sample of blood from a vein, usually in your arm; the sample is then sent to a laboratory for analysis, and the entire process typically takes only a few minutes.

A healthcare professional will draw a blood sample from a vein, typically in your arm. The sample is then sent to a laboratory where it is analyzed using specialized equipment. The base excess value is calculated from other measurements obtained during blood gas analysis, including pH, oxygen, and carbon dioxide levels.

Why is it important? This test is important because it can help detect a wide range of conditions, such as anemia, infections, and blood disorders, often before symptoms appear, and it allows your care team to monitor an existing condition or track how well a treatment is working over time.

Your body needs to maintain a precise balance between acids and bases to function properly. Base excess helps doctors determine if your blood is too acidic (acidosis) or too alkaline (alkalosis). This information is crucial for diagnosing and managing conditions that affect your body's acid-base balance, such as kidney disease, lung disease, diabetes, or severe infections.

What do the results mean? Your results show whether your blood cell counts fall within normal reference ranges; values that are too high or too low may point to conditions such as infection, anemia, or inflammation, but many factors can influence the numbers, so your doctor will interpret them together with your symptoms and medical history.

A normal base excess value typically ranges from -2 to +2 mEq/L. A positive value may indicate metabolic alkalosis, while a negative value may suggest metabolic acidosis. Your doctor will interpret these results along with other blood gas measurements to understand the underlying cause of any imbalance.