CBC, complete blood count, is a group of blood tests which estimates the different components contained in your blood. Your blood is composed of different cells, namely, red blood cells (RBC), white blood cells (WBC) and platelets.

Red blood cells (RBC)

Red blood cells are the type of blood cells which work by delivering oxygen to the body’s tissues. They have a typical lifetime of 120 days and the bone marrow is responsible for the continuous replacement- production and removal of the aged RBCs.

Apart from measuring their total number in the blood, the effective functioning of the RBCs can be ensured by assessing:

Hemoglobin

If RBCs function by transporting oxygen to various tissues, the value of Hemoglobin (Hb) in the blood determines the oxygen carrying capacity of RBCs.

Hematocrit

Hematocrit or packed cell volume (PCV) is the measure of percentage of blood that consists of your red blood cells.

Red blood cell indices (MCV, MCH, MCHC)

These indices provide information about the size of the RBCs and hemoglobin content of the same.

MCV, mean corpuscular volume, indicates the average size of your red blood cells

MCH, mean corpuscular hemoglobin, indicates the average amount of hemoglobin inside your RBCs

MCHC, mean corpuscular hemoglobin concentration, indicates the average concentration of hemoglobin inside your RBCs

White blood cells (WBC)

White blood cells are those blood cells which are part of the body’s immune system and play a major role in determination of one’s immunity. Produced in the bone marrow, WBCs help your body to keep away toxins and foreign invaders. There are five different types of WBCs and each has a different function. They include neutrophils, lymphocytes, basophils, eosinophils, and monocytes. You can usually find them placed under the heading ‘WBC differential’ in your blood reports.

Platelets

Platelets are tiny, colourless pieces of your blood which are incharge of the normal blood clotting mechanism. Basically, when there is an injury, platelets form clots at that site and help to stop the bleeding. They are also produced in your bone marrow.

Conditions that impact (increase or decrease) the full blood count are:

Anaemia

Anaemia is a disease in which the total number of red blood cells decreases or the hemoglobin level drops to such a low level that it leads to reduced oxygen flow in the body. Reduction in oxygen levels results in symptoms like difficulty in breathing, getting tired easily, yellowish skin, irregular heartbeats, headache, brittle nails, weakness and so on. Anaemia can cause decreased levels of RBCs, hemoglobin and hematocrit.

Dehydration

Dehydration is a condition in which there is lack of fluid intake and/ or too much fluid leaving the body (e.g. vomiting/ diarrhea). Even mild dehydration can lead to elevated levels of RBCs, hemoglobin and hematocrit.

Nutrient deficiency

Certain nutrient deficiencies can bring about a great deal of fluctuations in your blood reports. Lower or higher levels of RBCs, hemoglobin, hematocrit, RBC indices and some of the differential WBCs can generally be due to deficiencies of one or more of the following nutrients- protein, vitamin A, C, E, B6, B12, folic acid, iron, zinc, magnesium, selenium and copper.

Infection

Higher values of your white blood count are suggestive that the body is fighting off a bacterial/viral infection while low levels can be indicative of an autoimmune disorder, malnutrition or overuse or side effect of certain medications. Levels of differential WBCs can, however, show you the actual stage of infection, whether acute or chronic.

Allergy

Presence of allergies or food sensitivities also can be identified via a CBC test. Eosinophils generally tend to be raised if there is a sensitivity to certain foods like gluten, dairy and food additives and preservatives.

Inflammation

Inflammation is a response of body tissues to harmful stimuli, such as pathogens, toxins, damaged cells, or irritants such as excess insulin. Higher the inflammation, poorer is the internal metabolic health. Reduced levels of RBCs, hemoglobin, hematocrit and increased levels of WBCs and differentials are indicative of generalised systemic inflammation.

Apart from the conditions mentioned, higher exposure to toxins and oxidative stress can also lead to deranged levels of the blood cells.

If you are curious about your blood tests and want help in figuring them out, reach out to us and we’ll be happy to help you.

References:

https://my.clevelandclinic.org/health/diagnostics/4053-complete-blood-count

https://labtestsonline.org/tests/complete-blood-count-cbc