July 18, 2022

What Is a Complete Blood Count (CBC) Blood Test?

Key Takeaways

  • A complete blood count (CBC) test measures the number of red blood cells, white cells, and platelets in your blood to see if they are within the normal range.
  • You can have a CBC blood test performed at your doctor’s clinic or a hospital. You can also have the test taken in the comfort of your home with mobile phlebotomy services like Getlabs.
  • There is no need to fast before a CBC test.
  • A healthcare provider may request a CBC test to check for certain conditions, find underlying cause for symptoms, to track certain blood conditions, or to assess how certain medical treatments affect blood count.

Did you know that there are 150 billion red blood cells in just one ounce of blood? Your body is a powerhouse of production when it comes to manufacturing red cells, producing 17 million red blood cells per second. Red blood cells transport oxygen throughout your body and these are just one type of cell in your body.

White blood cells, meanwhile, are constantly defending your body from infection and disease. Though they make up less than 1% of your blood, they have a vital role to play. There are three types of white blood cells:

  • Granulocytes: fighting infections caused by bacteria, viruses, and fungus.
  • Monocytes: breaking down and eliminating dead cells from your body.
  • Lymphocytes: making antibodies and controlling the immune system.

Platelets, the third component of your blood, also make up less than 1% of your total blood. Their job is to control bleeding by clotting your blood.

A complete blood count (CBC) is a common blood test. The test measures your blood cell amount and examines your blood for several medical conditions. By screening all three types of blood cells, it can detect issues such as infection and inflammation. In this article, we will review CBC blood tests, how to get one, what to expect, and what your results mean.

What Is a Complete Blood Count (CBC) Test?

A CBC blood count measures the number of red blood cells, white cells, and platelets in your blood to see if they are within the normal range. They are used to check overall health and detect a wide range of health issues. Your healthcare provider may order a CBC test to:

  • Examine your general health: This could be part of a routine examination or checkup or to screen or evaluate health conditions such as anemia, leukemia, or an immune system disease.
  • Make a diagnosis: If you have been experiencing a certain range of symptoms, your doctor may want to see the results of a CBC test to help ascertain the underlying cause.
  • Monitor an existing condition: If you have already been diagnosed with a condition that affects your blood cells, your healthcare practitioner may order regular CBC tests to evaluate your condition. For example, a CBC blood test can be used to see if cancer has spread to the bone marrow.
  • Monitor medical treatment: A CBC test can be useful for monitoring your health if you are prescribed medications that may affect your blood cell counts.

When Should I Get a CBC Test?

Your healthcare provider may request that you take a CBC test for any of the following reasons:

To check for certain conditions such as:

  • Infection
  • Leukemia
  • Immune system disease

To find an underlying cause for symptoms such as:

  • Unexplained bruising
  • Joint pain
  • Fever and vomiting
  • Fatigue

To track certain blood conditions such as:

  • Anemia
  • Infection
  • Leukemia

To assess how certain medical treatments, such as chemotherapy, are affecting your blood count.

How Do I Get a CBC Test?

You can have a CBC blood test performed at your doctor’s clinic or a hospital. You can also have the test taken in the comfort of your home with mobile phlebotomy services like Getlabs.

Getlabs brings healthcare directly to you. If you would like your CBC blood test taken at home, all you need to do is book an appointment online. A Getlabs phlebotomist will come to your home, take your sample, and deliver it to a local laboratory to be analyzed. Getlabs’ service is safe and completely confidential.

What Should I Do Before My CBC Test?

Some types of blood tests require that you make special preparations during the 24 hours before the test, such as avoiding food and drinks. For a CBC test, there is no need to fast or follow any other special preparations. However, if you are having blood taken for other tests at the same time, your doctor may tell you to follow specific instructions.

What Should I Do During My CBC Test?

All our Getlabs phlebotomists are dedicated to providing a professional service that will put you at ease. Upon arrival, they will introduce themselves and show you their professional ID. When you invite them into your home, your specialist will show complete respect for your personal space and privacy.

Before taking your blood sample, your phlebotomist will confirm your ID and ask a few questions about your medical history and your general health. This is a good time to tell them if you have had problems with blood tests before, such as dizziness or fainting.

They will make sure you are sitting or lying in a comfortable position then examine your arm of choice, to select an appropriate vein. Usually, this will be on your inner forearm. Before inserting the needle, they will sterilize your arm with an antibacterial wipe.

Your phlebotomist will then insert a fine needle into your vein, attach a tube, and collect the blood sample. Once the sample has been collected, they will remove the needle and ask you to apply a little pressure at the needle site for a moment. They will then apply a bandage to the site. Typically, it takes less than five minutes to complete the test.

When Can I Expect My CBC Results?

Your CBC blood test results are often made available to your healthcare provider within 24-48 hours, depending on the laboratory and the type of lab test. Your doctor may call you with the results or post them to your laboratory's patient portal. Your doctor may also request a follow-up appointment.

How Do I Interpret My CBC Results?

When you get your CBC blood test results, they will be presented in two columns. The first column contains the reference range. The second column is your actual results. If the number in your results column is higher or lower than the number in the reference range column, your results are abnormal. Typically, the reference ranges are as follows:

Red Blood Cell Count (RBC)

Red blood cells carry oxygen throughout your body. Reference ranges are:

  • Men: 4.5 million to 5.9 million cells per microliter
  • Women: 4.1 million to 5.1 million cells/mcL

If your red cell count is low, you may be suffering from mild anemia. If it is high, it could be a sign of bone marrow disease or heart disease.

White Blood Cell Count (WBC)

White blood cells help protect your body from infection. The number of white blood cells in your body indicates how well your immune system is working or if you have an infection. This test is different from a white blood cell differential, which measures the number of each different white cell in your blood, such as eosinophils, basophils, leukocytes, and neutrophils. Reference ranges are:

  • Men: 5,000 to 10,000 cells/mcL
  • Women: 4,500 to 11,000 cells/mcL

If your white cell count is low, it means your body may struggle to fight off infection. If it is high, it usually indicates you have an infection.

Mean Corpuscular Hemoglobin (MCH)

Hemoglobin (HgB) is a protein in the blood that is responsible for transporting oxygen and gives blood its red color. It is contained in red blood cells known as erythrocytes. Mean corpuscular hemoglobin concentration reference ranges are:

  • Men: 14 to 17.5 grams per deciliter (gm/dL)
  • Women: 12.3 to 15.3 gm/dL

A low amount of hemoglobin means that you may have anemia or another blood disorder. A high amount of hemoglobin may mean you have a bone marrow disorder.

Hematocrit (HcT)

Hematocrit is the proportion of red blood cells in your blood. Reference ranges are:

  • Men: 41.5% to 50.4%
  • Women: 35.9% to 44.6%

A lower than normal hematocrit level may indicate anemia. A higher than normal count may be a sign of dehydration or something more serious such as heart or lung disease.

Platelet Count

Platelets are tiny cells that circulate in the blood and create blood clots when a vessel has been damaged, to stop you from bleeding. Reference ranges are:

  • Men and women: 150,000 to 450,000 platelets per microliter of blood.

A lower platelet count is a sign of a condition known as thrombocytopenia, A higher than normal level signifies a condition known as thrombocytosis.

Mean Corpuscular Volume (MCV)

This test is designed to measure the average size of your red blood cells. The average reference range is:

  • Men and women: 80–100 fl.

A lower than normal reading typically indicates microcytic anemia, while a higher than normal reading indicates macrocytic anemia.

Get CBC Blood Work Done at Home with Getlabs

Getlabs' provides a safe, friendly, and confidential blood sample collection service. We also transport your sample to a local lab for analysis. If you want to learn more about Getlabs, visit www.getlabs.com/faq to learn more.

This page is provided for educational and informational purposes only and does not constitute the provision of medical advice or professional services. The information provided should not be used for diagnosing or treating a health problem or disease, and those seeking personal medical advice regarding any of the tests and conditions referenced above are advised to consult with a licensed clinician. Always seek the advice of your qualified health provider regarding a medical condition and do not disregard professional medical advice or delay in seeking it because of any information on this page. If you think you may have a medical emergency, immediately call 911 or go to the nearest urgent care center or hospital.

Book an at-home lab collection

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