Peripheral Blood smear – Indications, Procedures, Results

Last updated: February 8, 2026 Medically reviewed by: RxHarun Orthopedic Specialist Doctor Reading time: 5 min read

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).

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:

The number and kinds of white blood cells ( differential , or percentage of each type of cell)
The number and kinds of abnormally shaped blood cells
A rough estimate of white blood cell and platelet counts

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:

Any known or suspected blood disorder
Cancer
Leukemia

A blood smear may also be done to monitor the side effects of chemotherapy.

Normal Results

Red blood cells 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 appearance of cells
Normal white blood cell differential

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

What Abnormal Results Mean

Abnormal results mean the size, shape, color, or coating of the red blood cells (RBCs) is not normal.

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

1+ means one quarter of cells are affected
2+ means one half of cells are affected
3+ means three quarters of cells are affected
4+ means all of the cells are affected

Presence of cells called target cells may be due to:

Deficiency of an enzyme called lecithin cholesterol acyl transferase
Abnormal hemoglobin , the protein in red blood cells that carries oxygen (hemoglobinopathies)
Iron deficiency
Liver disease
Spleen removal

Presence of sphere-shaped cells may be due to:

Low number of RBCs due to the body destroying them ( immune hemolytic anemia )
Low number of RBCs due to some red blood cells shaped like spheres ( hereditary spherocytosis )
Increased breakdown of RBCs

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:

Artificial heart valve
Disorder in which the proteins that control blood clotting become overactive ( disseminated intravascular coagulation )
Infection in the digestive system producing toxic substances that destroy red blood cells, causing kidney injury ( hemolytic uremic syndrome )
Blood disorder that causes blood clots to form in small blood vessels around the body and leads to a low platelet count ( thrombotic thrombocytopenic purpura )

Presence of a type of immature red blood cells called normoblasts may be due to:

Cancer that has spread to bone marrow
Blood disorder called erythroblastosis fetalis that affects a fetus or newborn
Tuberculosis that has spread from the lungs to other parts of the body through the blood ( miliary tuberculosis )
Disorder of the bone marrow in which the marrow is replaced by fibrous scar tissue ( myelofibrosis )
Removal of spleen
Severe breakdown of RBCs ( hemolysis )
Disorder in which there is excessive breakdown of hemoglobin ( thalassemia )

The presence of cells called burr cells may indicate:

Abnormally high level of nitrogen waste products in the blood ( uremia )

The presence of cells called spur cells may indicate:

Inability to fully absorb dietary fats through the intestines ( abetalipoproteinemia )
Severe liver disease

The presence of teardrop-shaped cells may indicate:

Myelofibrosis
Severe iron deficiency
Thalassemia major
Cancer in the bone marrow
Anemia caused by bone marrow not producing normal blood cells due to toxins or tumor cells (myelophthisic process)

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

Bone marrow does not produce enough healthy blood cells (myelodysplasia)
Spleen has been removed
Sickle cell anemia

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

Alpha thalassemia
Congenital hemolytic anemia
Disorder in which red blood cells break down when the body is exposed to certain drugs or is stressed because of infection ( G6PD deficiency )
Unstable form of hemoglobin

The presence of slightly immature red blood cells may indicate:

Anemia with bone marrow recovery
Hemolytic anemia
Hemorrhage

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

Lead poisoning
Disorder of the bone marrow in which the marrow is replaced by fibrous scar tissue (myelofibrosis)

The presence of sickle cells may indicate sickle cell anemia.

Risks

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:

Excessive bleeding
Fainting or feeling lightheaded
Hematoma (blood buildup under the skin)
Infection (a slight risk any time the skin is broken)

Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

References

Add references, clinical guidelines, textbooks, journal articles, or trusted medical sources here. You can edit this area later with a custom field named _rx_references.

Written by Dr. Harun Ar Rashid, MD - Arthritis, Bones, Joints Pain, Trauma, and Internal Medicine Specialist

Dr. Md. Harun Ar Rashid, MPH, MD, PhD, is a highly respected medical specialist celebrated for his exceptional clinical expertise and unwavering commitment to patient care. With advanced qualifications including MPH, MD, and PhD, he integrates cutting-edge research with a compassionate approach to medicine, ensuring that every patient receives personalized and effective treatment. His extensive training and hands-on experience enable him to diagnose complex conditions accurately and develop innovative treatment strategies tailored to individual needs. In addition to his clinical practice, Dr. Harun Ar Rashid is dedicated to medical education and research, writing and inventory creative thinking, innovative idea, critical care managementing make in his community to outreach, often participating in initiatives that promote health awareness and advance medical knowledge. His career is a testament to the high standards represented by his credentials, and he continues to contribute significantly to his field, driving improvements in both patient outcomes and healthcare practices. Born and educated in Bangladesh, Dr. Rashid earned his BPT from the University of Dhaka before pursuing postgraduate training internationally. He completed his MD in Internal Medicine at King’s College London, where he developed a special interest in inflammatory arthritis and metabolic bone disease. He then undertook a PhD in Orthopedic Science at the University of Oxford, conducting pioneering research on cytokine signaling pathways in rheumatoid arthritis. Following his doctoral studies, Dr. Rashid returned to clinical work with a fellowship in interventional pain management at the Rx University School of Medicine, refining his skills in image-guided joint injections and minimally invasive pain-relief techniques.