A blood smear is a blood test that provides details about the number and shape of blood cells. It is typically done as part of or in addition to a complete blood count (CBC). The test also known as Peripheral Smear; Blood Film; Manual Differential; Differential Slide; Red Blood Cell Morphology; Erythrocyte Morphology; Leukocyte Differential.
A blood smear is typically used as a follow-up test to abnormal outcomes on a total blood count (CBC) to evaluate the different types of blood cells. It may be used to help detect and/or keep an eye on numerous conditions that impact blood cell populations.
How Blood Smear Test is Performed
A blood sample is required.
The blood sample is sent to a lab. There, the laboratory professional looks at it under a microscope. Or, the blood might be analyzed by an automated device.
The smear supplies this details:
- The number and type of leukocyte (differential, or portion of each type of cell).
- The number and kinds of abnormally shaped blood cells.
- A rough quote 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 just a prick or stinging. Later, there may be some throbbing or a minor contusion. This quickly disappears.
Why Blood Smear Test is Performed
This test might be done as part of a basic health exam to help identify lots of diseases. Or, your health care supplier might recommend this test if you have signs of:
- Any understood or believed blood condition.
A blood smear might likewise be done to keep an eye on the side effects of chemotherapy.
Blood Smear Test: Normal Results
Red cell generally are the same size and color and are a lighter color in the center. The blood smear is considered normal if there is:
- Normal look of cells.
- Normal leukocyte differential.
Normal worth ranges may vary somewhat among different laboratories. Some labs use various measurements or test different samples, according to iytmed.com. Talk to your health care provider about the significance of your particular test outcomes.
Blood Smear Test: Abnormal Results Mean
Abnormal outcomes indicate the size, shape, color, or coating of the red blood cells (RBCs) is not normal.
Some irregularities may be graded on a 4-point scale:
- 1+ means one quarter of cells are affected.
- 2+ suggests one half of cells are impacted.
- 3+ suggests three quarters of cells are affected.
- 4+ indicates all the cells are impacted.
Existence 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 brings oxygen (hemoglobinopathies).
- Iron shortage.
- Liver disease.
- Spleen removal.
Presence of sphere-shaped cells might be due to:
- Low variety of RBCs due to the body damaging them (immune hemolytic anemia).
- Low number of RBCs due to some red blood cells formed like spheres (genetic spherocytosis).
- Increased breakdown of RBCs.
Existence 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.
Existence of fragmented cells may be because of:
- Synthetic heart valve.
- Condition where the proteins that manage blood clotting end up being overactive (shared intravascular coagulation).
- Infection in the digestive system producing hazardous substances that ruin red cell, causing kidney injury (hemolytic uremic syndrome).
- Blood disorder that causes embolism to form in little blood vessels around the body and causes a low platelet count (thrombotic thrombocytopenic purpura).
Existence of a kind of immature red cell called normoblasts might be because of:
- Cancer that has infected bone marrow.
- Blood disorder called erythroblastosis fetalis that affects a fetus or newborn.
- Tuberculosis that has actually spread from the lungs to other parts of the body through the blood (miliary tuberculosis).
- Disorder of the bone marrow where the marrow is changed 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 suggest:
- Unusually high level of nitrogen waste items in the blood (uremia).
The presence of cells called spur cells might show:
- Inability to fully soak up dietary fats through the intestines (abetalipoproteinemia).
- Severe liver disease.
The presence of teardrop-shaped cells may indicate:
- Severe iron deficiency.
- Thalassemia major.
- Cancer in the bone marrow.
- Anemia caused by bone marrow not producing normal blood cells due to toxins or growth cells (myelophthisic process).
The presence of Howell-Jolly bodies (a kind of granule) may suggest:
- Bone marrow does not produce sufficient healthy blood cells (myelodysplasia).
- Spleen has actually been gotten rid of.
- Sickle cell anemia.
The existence of Heinz bodies (little bits of altered hemoglobin) might suggest:
- Alpha thalassemia.
- Genetic hemolytic anemia.
- Disorder in which red cell break down when the body is exposed to particular drugs or is stressed because of infection (G6PD shortage).
- Unstable type of hemoglobin.
The presence of a little immature red cell may show:
- Anemia with bone marrow recovery.
- Hemolytic anemia.
The existence of basophilic stippling (a spotted look) might show:
- Lead poisoning.
- Condition of the bone marrow where the marrow is replaced by fibrous scar tissue (myelofibrosis).
The presence of sickle cells may indicate sickle cell anemia.
Findings on a blood smear that are abnormal are typically referred to a pathologist, often one with comprehensive experience in the study of blood (hematology), for further review and analysis. Depending on the results, follow-up testing including an examination of a bone marrow aspirate and biopsy may be needed for a diagnosis.
Veins and arteries differ in size from one patient to another and from one side of the body to the other. Acquiring a blood sample from some people may be more difficult than from others.
Other risks associated with having blood drawn are small but might include:
- Excessive bleeding.
- Passing out or feeling lightheaded.
- Hematoma (blood buildup under the skin).
- Infection (a minor risk any time the skin is broken).
Last modified: January 9, 2017