Site Map

Blood smear

Peripheral smear; Complete blood count - peripheral; CBC - peripheral

A blood smear is a blood test that gives information about the number and shape of blood cells. It is often done as part of or along with a complete blood count (CBC).

Images

Red blood cells, sickle cell
Red blood cells, tear-drop shape
Red blood cells - normal
Red blood cells - elliptocytosis
Red blood cells - spherocytosis
Acute lymphocytic leukemia - photomicrograph
Red blood cells - multiple sickle cells
Malaria, microscopic view of cellular parasites
Malaria, photomicrograph of cellular parasites
Red blood cells - sickle cells
Red blood cells - sickle and Pappenheimer
Red blood cells, target cells
Formed elements of blood

How the Test is Performed

A blood sample is needed.

The blood sample is sent to a lab. There, the lab technician looks at it under a microscope. Or, the blood may be examined by an automated machine.

The smear provides this information:

How to Prepare for the Test

No special preparation is necessary.

How the Test will Feel

When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.

Why the Test is Performed

This test may be done as part of a general health exam to help diagnose many illnesses. Or, your health care provider may recommend this test if you have signs of:

A blood smear may also be done to monitor the side effects of chemotherapy or to help diagnose an infection, such as malaria.

Normal Results

Red blood cells (RBCs) normally are the same size and color and are a lighter color in the center. The blood smear is considered normal if there is:

Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results.

What Abnormal Results Mean

Abnormal results mean the size, shape, color, or coating of the RBCs is not normal.

Some abnormalities may be graded on a 4-point scale:

Presence of cells called target cells may be due to:

Presence of sphere-shaped cells may be due to:

Presence of RBCs with an oval shape may be a sign of hereditary elliptocytosis or hereditary ovalocytosis. These are conditions in which RBCs are abnormally shaped.

Presence of fragmented cells may be due to:

Presence of a type of immature RBCs called normoblasts may be due to:

The presence of cells called burr cells may indicate:

The presence of cells called spur cells may indicate:

The presence of teardrop-shaped cells may indicate:

The presence of Howell-Jolly bodies (a type of granule) may indicate:

The presence of Heinz bodies (bits of altered hemoglobin) may indicate:

The presence of slightly immature RBCs may indicate:

The presence of basophilic stippling (a spotted appearance) may indicate:

The presence of sickle cells may indicate sickle cell anemia.

Risks

There is little risk involved with having your blood taken.Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight, but may include:

Related Information

Hypochromia
Polychromatophilia
Osmotic fragility test
Liver disease
Hemoglobin
Thalassemia
Hereditary spherocytic anemia
Anemia
Sepsis
Malignancy
Thrombotic thrombocytopenic purpura
Hemolytic-uremic syndrome
Hemolysis
Myelofibrosis
Disseminated tuberculosis
Hemolytic disease of the newborn
Prerenal azotemia
Bassen-Kornzweig syndrome
Sickle cell disease
Lead poisoning
Hemoglobin C disease
Hairy cell leukemia
Non-Hodgkin lymphoma

References

Bain BJ. The peripheral blood smear. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 148.

Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM. Blood disorders. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 124.

Merguerian MD, Gallagher PG. Hereditary elliptocytosis, hereditary pyropoikilocytosis, and related disorders. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 486.

Natelson EA, Chughtai-Harvey I, Rabbi S. Hematology. In: Rakel RE, Rakel DP, eds. Textbook of Family Medicine. 9th ed. Philadelphia, PA: Elsevier; 2016:chap 39.

Warner EA, Herold AH. Interpreting laboratory tests. In: Rakel RE, Rakel DP, eds. Textbook of Family Medicine. 9th ed. Philadelphia, PA: Elsevier; 2016:chap 14.

BACK TO TOP

Review Date: 1/13/2020  

Reviewed By: Laura J. Martin, MD, MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

ADAM Quality Logo

A.D.A.M., Inc. is accredited by URAC, for Health Content Provider (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics. This site complies with the HONcode standard for trustworthy health information: verify here.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- 2021 A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

A.D.A.M. content is best viewed in IE9 or above, Firefox and Google Chrome browser.