What is the Difference Between Peripheral Blood Smear and Bone Marrow Smear

The key difference between peripheral blood smear and bone marrow smear is that peripheral blood smear is a test used to examine mature red and white blood cells and platelets while bone marrow smear is a test to examine the process of hematopoiesis and evaluate the relative proportions, maturity of precursor cells, storage pool and other changes.

Blood provides nutrients and gases to the body tissues and removes waste in the body. Blood cells are made in the bone marrow. The cells of the blood and bone marrow are important as they are readily accessible and may give indications of the general state or clues to the diagnosis of the disease. Peripheral blood smear and bone marrow smear are two tests that are done to identify a number of pathological conditions in the laboratories. Both these tests are performed by qualified laboratory technicians. However, peripheral blood smear indicates the status of mature blood cells, while bone marrow smear indicates the process of hematopoiesis or blood cell formation.

CONTENTS

1. Overview and Key Difference
2. What is a Peripheral Blood Smear 
3. What is a Bone Marrow Smear
4. Similarities – Peripheral Blood Smear and Bone Marrow Smear
5. Peripheral Blood Smear vs. Bone Marrow Smear in Tabular Form
6. Summary – Peripheral Blood Smear vs. Bone Marrow Smear

What is a Peripheral Blood Smear?

Peripheral blood smear is a test healthcare providers use to examine mature red and white blood cells and platelets by looking at these blood cells under a microscope. This test helps a healthcare provider to identify the causes and characteristics of abnormal blood cell appearances or irregular cell counts. This test is usually used to diagnose diseases like leukemia, myelodysplastic syndrome, anemia, heart failure, lymphoma, autoimmune diseases, and malaria.

In this test, healthcare professionals will take a blood sample from a vein in the arm by using a small needle. The test is performed by spreading a drop of blood onto a glass plate and turning the drop into a thin film. The thin smear of blood is treated with chemicals that highlight specific characteristics of blood cells. Then, the sample will be examined under a microscope. The results of this test give a clear picture of the changes in blood cells and platelets that can be a sign of a disease. A few risks are involved with this test, including excessive bleeding, slight bruises, prickling or stinging sensation while taking blood, fainting or feeling lightheaded, hematoma, and infection.

What is a Bone Marrow Smear?

A bone marrow smear is a test used to assess the process of hematopoiesis or blood cell formation. A bone marrow smear is done using a small needle inserted into the bone to remove the soft bone marrow tissue, and then it is sent to a laboratory for checking under a microscope.

A pathologist can check the bone marrow through a bone marrow smear in certain situations such as unexplained anemia, abnormal numbers of blood cells (red blood cells, white blood cells, or platelets), lack of iron, cancers of blood-forming tissue such as leukemia or lymphoma, cancers that have spread to the bone marrow from other areas, and response to chemotherapy. The abnormal results in bone marrow smears can be due to cancers of bone marrow, anemia, thrombocytopenia, and other blood disorders. Furthermore, possible complications involved in bone marrow smear may include bruising and discomfort at the biopsy site, swelling and redness at the biopsy site,  prolonged bleeding at the biopsy site, infection near the biopsy site, fever, and worsening pain.

What are the Similarities Between Peripheral Blood Smear and Bone Marrow Smear?

• Peripheral blood smear and bone marrow smear are two tests that are done to identify a number of pathological conditions in the laboratories.
• Pathologists perform both tests.
• They are cheap diagnostic tests.
• Both tests may have a few possible risks.

What is the Difference Between Peripheral Blood Smear and Bone Marrow Smear?

Healthcare providers use a peripheral blood smear to examine mature red and white blood cells and platelets, while healthcare providers use a bone marrow smear to examine the process of hematopoiesis and to evaluate the relative proportions, maturity of precursor cells, storage pool, and other changes. Thus, this is the key difference between peripheral blood smear and bone marrow smear. Furthermore, a peripheral blood smear is usually performed with a complete blood count, while a bone marrow smear is usually performed with a bone marrow aspiration.

The infographic below presents the differences between peripheral blood smear and bone marrow smear in tabular form for side-by-side comparison.

Summary – Peripheral Blood Smear vs. Bone Marrow Smear

Peripheral blood smear and bone marrow smear are two tests that are done to identify a number of pathological conditions in the laboratories. A peripheral blood smear is a test that healthcare providers use to examine the mature red and white blood cells and platelets, while a bone marrow smear is a test that healthcare providers use to examine the process of hematopoiesis and to evaluate the relative proportions, maturity of precursor cells, storage pool and other changes. So, this summarizes the difference between peripheral blood smear and bone marrow smear.

Reference:

1.“ Peripheral Blood Smear – Clinical Methods.” NCBI Bookshelf.
2. IN, Afkhami M; Vergara-Lluri M; Brynes RK; Siddiqi. “Peripheral Blood Smears, Bone Marrow Aspiration, Trephine and Clot Biopsies: Methods and Protocols.” Methods in Molecular Biology (Clifton, N.J.), U.S. National Library of Medicine.

Image Courtesy:

1. “Peripheral blood smear” By Microrao – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Bone marrow WBC” By Bobjgalindo – Own work (CC BY-SA 4.0) via Commons Wikimedia