What does a Complete Blood Count measure? A complete guide

by Dr. Ajay Phadke
6 minutes
What does a Complete Blood Count measure? A complete guide

Our doctors and insurance companies often tell us to get a regular body checkup done. These tests are necessary to make sure that we stay healthy and deal with possible issues that we may have with our health. The blood that flows through our bodies is something that can be analyzed to tell us about our health, as it gives clues to doctors about our vital organs like the heart, liver, kidney, spleen, etc. Although blood does transport oxygen throughout our body, its composition can be telling of several issues within the body.

How does the CBC help us?

CBC profile tests or complete blood count are used to obtain these clues. Well-trained professionals collect samples of our blood either in laboratories or by visiting our homes for testing. CBC Blood tests measure the levels of different blood cells within our body, as well as of hemoglobin, which is the main component of blood that carries oxygen. The results of a CBC Lab test may look like a lot of complicated statistical tables, but it is actually very easy to interpret them.

Understanding the Complete Haemogram or CBC

The CBC focuses on looking at the levels of different blood cells, namely white and red blood cells and platelets. There are reference ranges within which the quantities of these cells need to be, and they give us clues about whether an individual may be suffering from diseases such as infections, anemia.

White Blood Cells. (WBCs):

These are the protectors of the body against infection. There are 5 types of white blood cells: basophils, eosinophils, neutrophils, lymphocytes, and monocytes. Neutrophils are the first to increase in amount during infection, while basophils release enzymes during allergies to help combat them. Usually, in case of infection, a rise in WBCs is seen.

Red Blood Cells (RBCs):

Red Blood cells carry oxygen to the different parts of the body. When RBC levels are very high, it may be a sign of dehydration, kidney issues, or even heart issues. However, low counts may indicate some form of nutritional deficiency, damage to the bone marrow (where these cells are produced), or even issues with the kidney.

Hemoglobin, Hematocrit & Corpuscular values:

Hemoglobin is the main part of the RBCs that transports oxygen. Hematocrit helps to see how much of the volumes of our total blood is occupied by the red blood cells. Thus, this helps to look at RBC counts. Mean corpuscular values help to look at the size of the RBC’s. Abnormal sizes may indicate Vitamin B12 deficiency, or even anemia (may be related to iron deficiency). Mean corpuscular hemoglobin helps look at the amount of hemoglobin in the red blood cells.

Platelets:

These cells help in clotting the blood when we get a wound. Low platelet counts may indicate an issue with clotting, and risk for excess bleeding. This can be a result of low Vitamin K. Very high counts may lead to the formation of clots in the blood vessels.

Comprehensive metabolic panel:

This test measures electrolytes in the body along with calcium, chloride, magnesium, phosphorus, potassium, and sodium among others. It also measures the body’s bilirubin, albumin and creatinine levels. Bilirubin is formed when hemoglobin breaks down, found in bile and food. High levels could indicate jaundice.

Albumin:

This is the main protein in blood plasma, which is the clear part of the blood. Low levels may indicate issues with the liver,  kidney, or nutrition. 

Creatinine:

This is produced from creatine, which supplies energy to the muscles. The kidneys filter this out of blood, and high levels may indicate issues with the kidney. 

Fasting Glucose:

The Complete Blood test may also include a fasting glucose test, which measures blood sugar levels in the fasting state (no food for 8-10 hours prior to testing, water is allowed). Increased glucose levels may indicate diabetes.

Lipid panel:

The lipid panel measures levels of fats in the blood. It measures Low-Density Lipoprotein (LDL Cholesterol) or bad cholesterol, which can cause blockages in our blood vessels. High levels of LDL increase the risk of heart issues. It also measures High-density lipoprotein (HDL Cholesterol) or good cholesterol that helps to transport fats. Lower levels of HDL may indicate risk for heart issues. The lipid panel also measures triglycerides, which come from extra energy from food. Higher levels of these in the blood can be indicative of heart and coronary artery diseases.