From the Guidelines
A CBC with peripheral smear is a crucial diagnostic tool for evaluating anemia and other blood disorders, as it provides a comprehensive assessment of blood cells and can reveal abnormalities not detected by automated cell counters. This test is particularly valuable for diagnosing various blood disorders including anemias, leukemias, infections, and platelet disorders, as noted in the study by 1. The peripheral smear allows healthcare providers to visually assess the size, shape, and appearance of blood cells, which can identify specific cell abnormalities like sickle cells, target cells, blast cells, or parasites within red blood cells.
According to the study by 1, a complete blood count (white blood cells, hemoglobin, and platelets) assesses bone marrow function, and abnormalities in two or more of these cell lines should be evaluated carefully and likely warrant discussion with a hematologist. The study by 1 also emphasizes the importance of a visual review of the peripheral blood smear in the initial assessment of anemia.
Key points to consider when ordering a CBC with peripheral smear include:
- The test requires a standard blood draw, typically from a vein in the arm
- Results are usually available within 24-48 hours
- No special preparation is needed before the test
- A CBC with peripheral smear provides more comprehensive information than a standard CBC alone and is often ordered when blood cell abnormalities are suspected or need further investigation.
Overall, a CBC with peripheral smear is a essential diagnostic tool for evaluating blood disorders, and its use is supported by the most recent and highest quality studies, such as 1.
From the Research
CBC with Peripheral Smear
- A Complete Blood Count (CBC) with differential includes a blood smear that is examined by a medical technologist and is available for the physician 2.
- The peripheral blood smear review is an essential part of the emergency department evaluation of bleeding disorders, anemia, infectious disorders, and suspected leukemia 2.
- A CBC is one of the most common laboratory tests in medicine, and 10% to 20% of results are reported as abnormal, making it essential for clinicians to understand the test basics and have a structured action plan when confronted with abnormal CBC results 3.
- A microscopic examination of an appropriately prepared and well-stained blood smear by a knowledgeable laboratory professional is necessary and clinically useful in various circumstances, including verifying flagged automated hematology results and determining if a manual differential leukocyte count needs to be performed 4.
Purpose and Criteria for Blood Smear Examination
- A blood smear scan serves to verify flagged automated hematology results and determine if a manual differential leukocyte count needs to be performed 4.
- Blood smear examination/manual differential leukocyte count with CBC provides the complete hematologic picture of the case, at least from the morphologic standpoint 4.
- Blood smear review with or without interpretation serves to ensure that no clinically significant finding is missed, besides providing diagnosis or diagnostic clues, particularly if and when interpreted by a physician 4.
Detection of Anemia
- A complete blood count (CBC) gives significant information on changes in the size and shape of red blood cells and an indication of inclusion bodies that will help exclude anemia 5.
- Red blood cell (RBC) indices suggest potential reasons for the anemia in a particular patient, and it is necessary to look at the peripheral blood smear (PBS) and RBC indices and histogram to evaluate anemia adequately 5.
- The diagnostic capabilities of the PBS procedure are expected to match with RBC histograms and indices in the CBC report for the detection of anemia 5.
Clinical Usage of CBC
- The complete blood count is one of the most frequently ordered laboratory tests in medicine, and its components include the red blood cell count, hemoglobin, hematocrit, red blood cell indices, reticulocyte count, white blood cell count and differential, and platelet count 6.
- Understanding the function, life cycle, and physiology of the various cell components can aid in understanding the multiple uses of the complete blood count, including difficult diagnoses and monitoring treatments for hematologic disorders and other medical problems 6.