A blood smear is basic test that is used to determine diagnostically if there are any abnormalities within the blood. The focus will be on the three primary types of cells that can be found within the blood: red blood cells [RBCs], white blood cells [WBCs], and platelets.
When there are changes to the size and shape of these cells, then this can be an indication that there is something abnormal happening within the body. Alterations to RBCs, for example, can change how oxygen is transported throughout the body. Changes to WBCs can indicate the presence of an illness or disease. Platelet changes may affect how the blood is able to clot.
Why Is the Peripheral Blood Smear Test Ordered?
Most patients will receive an order for this blood test because there is a suspected vitamin or mineral deficiency. It may also be ordered as part of a regular annual exam. Some medical providers will also order a peripheral blood smear test because of unusual symptoms that are discovered upon examination. This may include unexplained anemia or jaundice, bruising patterns that are unusual, chronic bone pain, or influenza symptoms that do not go away.
For those who had a complete blood count ordered and the results of this test were abnormal, the peripheral blood smear test is usually the next step.
Before having the blood draw, it is important to discuss with a medical provider about the medications and supplements that are being regularly taken. Certain drugs, vitamins, and supplements may alter the results of the blood test. People with a cancer of the blood, hemophilia, or have received a recent blood transfusion may also receive inaccurate results.
The results of the peripheral blood smear test will generally be reported as normal or abnormal. Most people will receive normal results from this test.
How Is the Peripheral Blood Smear Test Examined?
A drop of blood is placed between two glass slides. Although there are literally millions of cells that are in that drop of blood, along the edge of the droplet the cells are only one layer thick. This allows the individual cells to be counted and examined with the help of a microscope.
What Do Abnormal Peripheral Blood Smear Test Results Mean?
Because this blood test takes a look at the three primary cell components of the blood, each cell type may have abnormalities that are detected. RBCs, WBCs, and platelets that are abnormal are reflective of very different, yet still specific health conditions that may be present.
If there is an RBC abnormality.
A disorder that is detected in the red blood cells could be an indication of a number of different health concerns. The most common reason for an RBC abnormality is an iron deficiency or a lack of Vitamin B-12. Depending on an individual’s medical history, these additional concerns may also be evaluated.
1. Sickle cell disease.
2. Digestive system infections that produce RBC toxins.
3. COPD, emphysema, and other breathing disorders.
If there is a WBC abnormality.
When a disorder is detected in the white blood cells, this may indicate the presence of a chronic disease or infection. Parasites, fungal infections, or long-term virus infections such as HIV, hepatitis, or EBV may be indicated by an abnormal result. Specific patients may also be evaluated for these additional concerns.
1. Lymphoma or multiple myeloma.
2. Acute leukemia.
3. Infectious diseases such as malaria.
If there is a platelet abnormality.
If an abnormality in the platelets is discovered, then this is also commonly caused by a vitamin deficiency. Viral and bacterial infections may also cause a platelet abnormality. If these are ruled out, then certain types of leukemia or other bone marrow disorders may be considered. These additional conditions may also change the peripheral blood test results.
1. Liver disease.
2. Kidney disease.
3. Hypothyroidism.
What Happens After an Abnormal Test?
If there is an abnormality on the peripheral blood test that concerns a medical provider, then the next step is typically additional testing. Although this blood test can help to determine if there is something happening within the body, it is not a specific test that can lead to a diagnosis.
For many people, the peripheral blood test is either a first or second step towards a specific diagnosis. Most people who have this blood test will have a normal result. If abnormal results do occur, then use this information to discuss the results with a medical provider to determine how medically significant the results may be.