|Rules for Bone Marrow Differentials, continued|
Bone marrow smears can be very cellular and it can be difficult to keep track of where you are on the smear while keeping your correct hand position on the keyboard . Having a good strategy to use when counting cells and performing differentials can make this less difficult. On peripheral blood differentials, it is easy to observe and count each cell individually as the stage is moved to bring the next field into view. However, with bone marrows, the total number of keys that need to be used on the differential counter is greater than the number that need to be used with a peripheral blood smear and the number of cells per field is also increased dramatically, making it easy to lose track of the cells on the smear or one's hand/keyboard placement. It can be simpler and less stressful to work on the quadrant system. There are two different ways to do this: Divide the field into quadrants. Count the individual cells in each quadrant separately. This decreases the number of cells into more manageable bites. However, you still have the increased number of cell types to deal with and possible keyboard frame-shifts. Divide your keyboard into quadrants. Search your field for a limited number of cell types and tally all you see before moving on to the next grouping of cell types. Once you tally all your groups then move on to the next field (e.g., lymphocytes, monocytes, macrophages, eosinophils, basophils, plasma cells, erythroids, segmented neutrophils, bands, etc). You can make these small groupings for any cells as long as you cover the entire list of cell types that your laboratory reports in its bone marrow differential protocol. Remember that blasts are identified by cell type and there will usually be a separate key for pronormoblasts, myeloblasts, lymphoblasts, and possibly monoblasts and plasmablasts. It is possible to combine both methods, using the keyboard quadrant technique with a restricted portion of the total microscope field. This is useful when you are getting close to your total tally and do not want to alter the balance by only counting one cell type for the last few cells.
|Long Slide Preparation Techniques: Wedge Smear|
The simplest way to prepare a bone marrow smear is to treat it similarly to a peripheral blood smear. A drop of well-mixed marrow sample is placed near one end of slide and a second slide is used to draw it the length of the slide until a feathered edge is produced. The slide should be air dried and labeled with the patients identification, date of collection, sample site or lab accession number (depending on the laboratory's standards).If the marrow is rich in spicules or fragments, there will be "clumps" of marrow fragments at the end of the feathered edge where these fragments are deposited. Fragments, also known as spicules, are aggregates of bone marrow cells that are pulled from the bony matrix of the marrow space (trabecula) during the aspiration process. They represent what will be seen on the bone marrow biopsy between the bony trabecula, once the biopsy is decalcified and sectioned. Since these spicules are cohesive aggregates of cells, they will not spread well if a wedge smear technique is used, which may make it difficult to identify cell types present in the thicker parts of the spicules.Another disadvantage of using the wedge technique to make smears of bone marrow is the fact that the distribution of cells will not be uniform or representative of how the cells are distributed in the marrow. This technique tends to skew the spread, based on the size of the cells present. Just as the larger bone marrow spicules wind up at the end of the feathered edge, so do cells like megakaryocytes and other aggregates, such as tumor clumps. However, since there tends to be more of a feathered edge in this type of preparation, it can be preferable to other methods when the marrow to be evaluated has no fragments. Long slide prepared smears are particularly useful when evaluating leukemic patients at days 8 and 15 of therapy, when the cellularity is greatly reduced and clear morphology is needed to differentiate between treated lymphocytes and treated blasts. In this case, it is easier to distinguish blasts from lymphocytes when this smear technique is used.
|What are Erythrocyte Inclusions?|
Erythrocyte inclusions are elements that may be present in red blood cells (RBCs). The appearance, composition, and associated physiology of the inclusions are specific for each type of inclusion. Identification and reporting of these inclusions are important because their presence may indicate diseases or disorders.Many erythrocyte inclusions can be visualized on a Wright-stained smear. However, some erythrocyte inclusions can only be observed by using a special stain. For example, to confirm the presence of Heinz bodies, hemoglobin H bodies, or reticulocytes, smears must be prepared after staining an aliquot of fresh whole blood with a supravital stain such as new methylene blue or brilliant cresyl blue. The image on the right is a peripheral blood smear prepared after staining the blood sample with a supravital stain; Heinz bodies, which are clumps of precipitated hemoglobin, are indicated by the arrows. To detect siderosomes, a stain must be used that is specific for iron, such as Prussian blue.
|While performing a peripheral blood smear review, you observe the cells indicated by the arrows on this Wright-Giemsa stained slide. How would you classify these cells?||View Page|
|In which of the following disorders would you probably observe coarse basophilic stippling on a Wright-stained peripheral blood smear?||View Page|
The presence on a Wright-stained peripheral blood smear of relatively evenly-distributed dark-blue particles or granules of varying size in the cytoplasm of erythrocytes is referred to as basophilic stippling. These dark-blue or blue-purple granules are predominantly precipitates of ribosomes (RNA) and may indicate impaired hemoglobin synthesis, probably due to the instability of RNA in the young cell. The erythrocyte containing these inclusions may stain normally in other respects or it may be polychromatophilic.The basophilic stippling that is clinically significant is coarse stippling. Fine stippling is often noted in polychromatophilic red cells, and sometimes in other red cells, and is generally not significant. Coarse basophilic stippling may be seen in sideroblastic anemias, lead poisoning, myelodysplasias, and thalassemias.
Howell-Jolly bodies are round, smooth, almost pyknotic, dark-purple bodies ranging in size from 0.5 to 1.0 micron in diameter. These RBC inclusions contain DNA. Howell-Jolly bodies are thought to be nuclear remnants or aggregates of chromosomes that have separated from the mitotic spindle and remain behind after the remainder of the RBC nucleus is expelled. The spleen normally removes these bodies from the RBCs. However, Howell-Jolly bodies can be observed on a Wright-stained peripheral blood smear post-splenectomy or when the spleen is not functioning properly. Howell-Jolly bodies may also be seen in hemolytic anemias such as sickle cell anemia.When Howell-Jolly bodies are present, they usually occur singly, as shown in the image on the right. It is possible, though, that two or more may be seen in a single RBC, usually occurring in the presence of megaloblastic anemia or abnormal erythropoiesis.
|In which of the following conditions would you expect to find Howell-Jolly bodies?||View Page|
Pappenheimer bodies may be seen in the cytoplasm of mature and immature erythrocytes on a Wright-stained peripheral blood smear. They appear as small dark purple granular bodies of varying size, frequently clustered in groups of two, three, or more near the edge of the cell. They are composed of degenerating cellular remnants that contain iron. Pappenheimer bodies are most likely caused by accelerated red cell division or impaired hemoglobin synthesis.
|Match the descriptions below with the erythrocyte inclusions from the drop down box that they describe. The descriptions refer to the appearance of the inclusions on a Wright-stained peripheral blood smear.||View Page|
|The inclusions that are indicated by the arrows on this Wright-Giemsa stained peripheral blood smear are most likely Pappenheimer bodies.||View Page|
|In which of the following conditions might Cabot rings be observed in erythrocytes on a Wright-stained peripheral blood smear?||View Page|
|RBC Morphology in Sickle Cell Trait (HbSA)|
Codocytes, also referred to as target cells can be observed on the peripheral blood smear from a patient with sickle cell trait (HbSA), as indicated by the arrows in the image on the right. Codocytes are cells that can be seen in hemoglobinopathies, thalassemia, iron deficiency, and other anemias where there is a decrease in the mean corpuscular hemoglobin concentration (MCHC).Sickle cell trait will not usually show completely sickled cells because of the HbA that is present in each cell. HbA usually comprises greater than 60% of the hemoglobin in HbSA.However, rare drepanocytes (sickle cells) and occlusive crisis may be found during times of extreme exercise and fluid restriction.
|CBC results and RBC morphology|
A patient with sickle cell trait is asymptomatic except under extreme hypoxic conditions. CBC results for patients with sickle cell trait (HbSA) can be near normal or reflect a slight anemia (as shown in this case). A typical automated CBC report and peripheral blood smear for an asymptomatic adult male patient with HbSA appears below. Reference intervals may vary between facilities and are dependent on patient age and gender. The reference intervals that are shown below are specific to this case. Parameter Patient Result Reference Interval White blood cell count (WBC) 5.3 3.8 - 9.8 x 109/L Red blood cell count (RBC) 4.78 4.50 - 4.70 x 1012/L Hemoglobin 12.9 13.8 - 17.2 g/dL Hematocrit 39.7 40 - 50% MCV 83 83 - 101 fL RDW 14.2 11 - 14.5 Platelet count 250 140 - 440 x 109/L
|CBC and RBC morphology|
CBC results for patients with sickle cell disease (HbSS) can reflect a slight, moderate, or severe anemia. The CBC and peripheral blood smear shown below are those of an African-American 12-year-old male patient with HbSS.Reference intervals may vary between facilities and are dependent on patient age and gender. The reference intervals that are shown below are specific to this case. Parameter Patient Result Reference Interval White blood cell count (WBC) 18.9 3.2 - 9.8 x 109/L Red blood cell count (RBC) 3.88 4.50 - 5.70 x 1012/L Hemoglobin 10.0 13.8 - 17.2 g/dL Hematocrit 32 41 - 50% MCV 82 80 - 110 fL RDW 22.7 11 - 14.5 Platelet count 458 140 - 440 x 109/L
|CBC and RBC morphology|
Patients with double heterozygous Hemoglobin SC Disease (HbSC) may have a slight to moderate anemia. The CBC and peripheral blood smear for an adult patient with HbSC appear below. The arrow in the image of the peripheral blood smear is pointing to a HbSC crystal.Reference intervals may vary between facilities and are dependent on patient age and gender. The reference intervals that are shown below are specific to this case. Parameter Patient Result Reference Interval White blood cell count (WBC) 10.4 4.5 - 11.0 x 109/L Red blood cell count (RBC) 3.98 4.50 - 4.70 x 1012/L Hemoglobin 10.5 11.7 - 16.0 g/dL Hematocrit 33.5 35 - 47% MCV 84 81 - 101 fL RDW 16.0 11 - 14.5 Platelet count 160 150 - 450 x 109/L
|CBC and RBC morphology|
CBC results for patients with double heterozygous condition of Sickle Cell with Beta thalassemia (HbS/Bthal) can be asymptomatic or demonstrate a slight to moderate anemia. The CBC and peripheral blood smear for a patient with HbS/Bthal, which appear below, reflect results more consistent with thalassemia than hemoglobinopathy. The hemoglobin electrophoresis results on the following page revealed this condition.Reference intervals may vary between facilities and are dependent on patient age and gender. The reference intervals that are shown below are specific to this case. Parameter Patient Result Reference Interval White blood cell count (WBC) 11.4 4.0 - 11.0 x 109/L Red blood cell count (RBC) 6.37 4.5 - 5.9 x 1012/L Hemoglobin 13.6 13.8 - 17.2 g/dL Hematocrit 38.1 41 - 53% MCV 59.9 80 - 100 fL RDW 18.9 12 - 14.6 Platelet count 150 - 440 x 109/L
|CBC and RBC morphology|
CBC results for patients with Sickle Cell Disease who have a hereditary persistence of fetal hemoglobin (HbS/HPFH) may appear normal or demonstrate a mild to moderate anemia. The CBC and peripheral blood smear for a patient with HbS/HPFH appear below.Reference intervals may vary between facilities and are dependent on patient age and gender. The reference intervals that are shown below are specific to this case. Parameter Patient Result Reference Interval White blood cell count (WBC) 6.4 3.8 - 9.8 x 109/L Red blood cell count (RBC) 4.78 4.50 - 5.90 x 1012/L Hemoglobin 11.9 13.8 - 17.2 g/dL Hematocrit 37.7 41 - 50% MCV 81 80 - 100 fL RDW 13.2 12 - 14.6 Platelet count 230 140 - 440 x 109/L
Glassy, Eric F.,(Ed). Color Atlas of Hematology: An Illustrated Field Guide Based on Proficiency Testing. 1998. College of American Pathologists Hematology and Cliical Microbiology Research Committee. College of American Pathologists, Northfield, IL 60093-2750.Hookey,L., Dexter, D., Lee,D. H. The Use and Interpretation Of Quantative Terminology In Reporting Red Blood Cell Morphology. Laboratory Hematology 7:85-88, 2001.Peterson P, Blomberg DJ, Rabinovitch A, Cornbleet PJ. Physician Review of the Peripheral Blood Smear: When and Why. For the Hematology and Clinical Microscopy Resource Committee of the College of American Pathologists. Laboratory Hematology 7:175-179, 2001
|An isolated acanthocyte is most likely of little importance on an otherwise normochromic, normocytic peripheral blood smear.||View Page|
|The RBC inclusions shown in the photograph represent which of the following?||View Page|
|The peripheral blood smear represented by the image on the right was submitted for hematologic review. The identification of the RBC inclusions shown are most likely identified as:||View Page|
|The presence of erythrocytes with altered morphology (as indicated by the arrows in the image to the right) has a close association with each of the following conditions EXCEPT:||View Page|
|A 5-year-old girl was brought to the emergency department with bloody diarrhea and severe abdominal pain. A complete blood count produced these results:CBC ParameterPatient ResultReference IntervalWBC9.6 x 109/L4.3 - 10.8 x 109/LHemoglobin9.1 g/dL11.5 - 13.5 g/dLHCT28%37 - 48%MCV80 fL86 - 98 fLRDW13.111 - 15Platelets90.1 x 109/L150 - 450 x 109/LThe peripheral blood smear is represented in the image to the right. Which of the following condition(s) could be present in this patient when considering the information above and the cells indicated by the arrows on the peripheral smear?||View Page|
|A 12-year-old child presents with jaundice and scleral icterus. The image to the right captures a representative section of the peripheral blood smear. Which of the following are significant findings that should be included on the report?||View Page|
|Case Study The image on the right is representative of the peripheral blood smear from a five-month-old immigrant from Asia. Her mother was concerned that the child was not eating well. Her spleen was palpable.These blood count results were reported:ParameterPatient ResultReference IntervalRBC5.5 x 1012/L3.1 - 4.5 x 1012/LHgb9.6 g/dL9.5 - 13.5 g/dLHCT30.4%29- 41%MCV55.4 fl74 - 108 flMCH17.5 pg25 - 35 pgMCHC31.6 g/dL30 - 36 g/dLRDW34.9%11 - 15%Reticulocyte10.9%0.5 - 4.0%Knowing that the family is from a region of Thailand where HbE carriers are prevalent, the physician ordered a hemoglobin electrophoresis. The hemoglobin electrophoresis detected HbE. Based on the blood count results and this representative microscopic field, which of the following peripheral blood findings should be reported?||View Page|
|Hemoglobin E (Hb E) and HbE/Beta Thalassemia|
Homozygous Hb E is common in Southeast Asia and presents with very mild anemia and seldom requires transfusion. Over 30 million people in the world are HbE carriers, making this abnormal hemoglobin almost as common as HbS. Hb E is uncommon in North America and in Europe, but with changing immigration patterns, Hb E and related diseases cannot be ignored. Peripheral blood smear findings of target cells, microspherocytes, red cell hypochromia, red blood cell fragments, and nucleated red blood cells may be noted. Evidence from hemoglobin electrophoresis is required to establish a diagnosis.Clinically, a very important and severe disease is Hb E/beta thalassemia in which there is hemolysis requiring repeated transfusions. Severe anemia, low MCV, and elevated RBC are characteristic of Hb E/beta thalassemia.
|The arrangement of erythrocytes on this peripheral blood smear can be associated with each of the following conditions except:||View Page|
Ovalocytes/elliptocytes are oval or elliptical red blood cells that range in shape from slightly egg-shaped to rod or pencil forms. They have normal central pallor with the hemoglobin concentrated at the ends of the elongated cells. The ends of the cells are blunt and not sharp like sickle cells.A rare ovalocyte/elliptocyte (less than 1%) may be found on almost any peripheral blood smear. However, when they comprise more than 25% of the red blood cells on the blood smear, hereditary elliptocytosis (HE) is probable. In most cases, patients are asymptomatic while having normal red blood cell life spans, although a mild anemia may occur. Resistance to malarial infection may be a beneficial attribute of HE.
|The complete blood count was obtained from a patient recently admitted to the emergency room. The red blood cell indices obtained revealed an MCV of 115 femtoliters (fL) (normal range 80 - 90 fL). The patient met the criteria for a peripheral blood smear examination. A representative field is shown on the right.Which of the following conditions may be indicated by the results seen on this peripheral blood smear?||View Page|
|Criteria for Peripheral Blood Smear Review|
When an Initial analysis of red blood cells (RBCs) from an automated instrument are found to be abnormal, many laboratories will microscopically evaluate the peripheral blood morphology of the RBCs. This important step can help to establish which, if any, abnormalities are present as well as correlate possible disease states or conditions associated with the findings. Most laboratories will employ guidelines for review of the peripheral blood smear for RBC morphology. Though each laboratory will create their own guidelines, the following are a few examples that could trigger a manual, microscopic peripheral blood smear review:Hemoglobin: < 8 or >18 g/dL (<10 or > 21g/dL in a newborn)Hematocrit: <20% or > 60% in adults (<40% or >65% in a newborn)MCHC: <29 g/dLMCV: <69 femtoliters (fl) or >110flFlags generated by the hematology analyzer that indicate possible red cell abnormalities or spurious results In most laboratories, when these findings are noted, they should be followed up with a peripheral blood smear review for RBC morphology.
|Introduction to Red Blood Cell Morphology Reporting|
After an automated complete blood count (CBC) analysis has determined that abnormal RBC morphology may be present, a well-made and well-stained peripheral blood smear should be prepared. When a peripheral blood smear is made for the purpose of evaluating RBC morphology, accurate recognition and identification of RBC morphologic abnormalities can be an invaluable aid in the diagnosis of a variety of disorders. It is important to understand that red blood cell morphology report formats tend to vary widely among laboratories. Despite the standardization of many laboratory technologies and test result formats, there are still various protocols in use in the area of red cell morphology reporting. Current methods of reporting and quantifying red cell morphology include descriptive terms such as 'rare,' 'occasional,' 'many,' 'slight,' or 'moderate,' as well as numerical gradings of 1+, 2+, 3+, etc. Regardless of the terminology used, consistency is of greater importance. There must be a defined, semi-quantitative scheme that dictates how many cells with a specific morphologic abnormality qualify as "rare" or "many," and so on. The report format must be clear and useful to the physician. Some morphologic abnormalities are quite specific and diagnostic, but others are ambiguous and of little diagnostic significance.A well-defined, semi-quantitative report format for RBC morphology should be based on clinical significance. Some morphologic abnormalities are significant, even when they occur in very low numbers. These include:SchistocytesSickle cellsAcanthocytesSpherocytesTeardrop cellsPolychromatophilic cells Other morphologic abnormalities are significant only when seen in considerable numbers. These include:MacrocytesMicrocytesOvalocytesBurr cells (echinocytes)Target cellsStomatocytesHypochromic cells A final category includes morphologic abnormalities that do not need to be quantified as it serves no purpose; these findings can be noted as "present." These include RBC agglutinationRouleauxDimorphic or double red cell populationAn example of a standardized reporting format is given on the following page.
|This oil immersion field (1000x) is representative of the peripheral blood smear. Which report is the most appropriate for documentation of the finding of teardrop cells using the Guidelines for Standard Reports that were described on the previous pages and included as a PDF in this question?||View Page|
|Rouleaux and Agglutination|
Cell TypeImageCellular DescriptionAssociated Diseases and ConditionsRouleauxRed blood cells (RBCs) appear as "stacked coins."Cells overlap each otherStacked-coin morphology is noted throughout the peripheral blood smear Conditions associated with increased concentrations of globulins and/or fibrinogenHyperparaproteinemiasWaldenstrom's ,macroglobulinemiaMultiple myelomaChronic inflammatory disordersAgglutinationClusters of RBCs due to antigen/antibody reactions in vivioCannot distinguish the outlines of individual RBCsCold agglutinins (most often IgM antibodies)Paroxysmal cold hemoglobinuria
|Introduction to Red Blood Cell Nonneoplastic Conditions Case Studies|
Now that you have reviewed the red blood cell morphology tables, we will incorporate disease state correlations with the help of case studies and questions with answers. The following case studies and questions will be presented in groups of related morphologic findings on the peripheral blood smear. The case studies and questions will contain multiple choice and true/false questions for you to answer. There will be helpful information regarding the morphologies noted and disease states present displayed in the feedback sections for each question- so be sure to review the explanations after answering the questions. Enjoy!
|A 49-year-old male with pneumonia was treated with high-dose intravenous penicillin. He became jaundiced with yellow sclera. The image on the right is typical of other fields that were observed on his peripheral blood smear.Since penicillin may, in some individuals, cause autoimmune hemolytic anemia, the clinician requested a direct antiglobulin test (DAT) be performed. The DAT was positive, indicating that antibodies to the drug were produced, which then attached to the drug on the surface of the red cells. Hemolysis occured due to the drug-induced antibody attachment, leaving the patient with various abnormal red blood cell morphologies. Which of the following cell types would you report for this patient?||View Page|
|A teenage boy is visiting his doctor uder the suspicion of a viral illness. He has always been relatively healthy without many illness-related complaints. The doctor decides to order a laboratory workup including a complete blood count. A peripheral blood smear is reviewed. The image on the right is a representative field, with a predominance of the arrowed cells throughout the smear. Which of the following conditions would be most consistent with this patient's history and peripheral blood picture?||View Page|
|A CBC performed on a 10-year-old African-American male who was brought to the emergency department with rapid, shallow breathing and fever provided the following results:ParameterPatient ResultReference IntervalWBC28.0 x 109/L3.2- 9.8 x 109/LRBC3.88 x 1012/L4.50 - 5.70 x 1012/LHemoglobin10.0 g/dL13.6 - 17.2 g/dLMCV82 fL80 - 110 fLRDW 2311 - 14.5Reticulocyte 8.0%0.5 - 1.5%The image on the right is a representative field from the peripheral blood smear. What cells are indicated by the arrows in this smear?||View Page|
|The cells included in the composite image were found in the peripheral blood smear of a patient with the following results:total WBC of 24.5 x 109/L. Differential count:myelocytes 1 metamyelocytes 4 band neutrophils 15 segmented neutrophils 40 monocytes 8 eosinophils 2 basophils 1 lymphocytes 29This hematologic picture is most consistent with:||View Page|
|Select the letter representing the cell that can be seen in increased concentrations in the peripheral blood smear during immediate hypersensitivity reactions:||View Page|
|The globular inclusions in this cell are fat droplets.||View Page|
|Approximately 80 - 90% of the neutrophils on the peripheral blood smear of a young man are similar to those in the image. This peripheral smear most likely represents which condition?||View Page|
|The upper image of a peripheral blood smear reveals RBC rouleaux formation. Several blood cells that are similar in appearance to the one indicated by the arrow in the bottom image are also seen on the smear. Which of the following conditions is associated with both of these findings?||View Page|
|The image shows a representative field from a peripheral blood smear. If similar blood cell morphology is seen throughout the smear, metastatic carcinoma should be considered.||View Page|
|Peripheral Blood Smear Preparation|
A reproducible blood smear review requires every peripheral smear be prepared for consistent cellular distribution and proper clarity. Well-made peripheral smears can be prepared by starting with only a drop of blood at one end of a clean glass slide. The drop is smeared lightly and quickly with a wedge technique so as to leave a thin "feather" edge where all cells may be examined individually, particularly red blood cells. After staining the slide, the examination begins. The site of examination is chosen; away from clumping, piling, or stacking of the red blood cells. This can most likely be observed at a site five or six oil fields from the end of the feathery portion (about 100 red cells per field). Such an area for examination is illustrated in the image below.
|An automated platelet count of 40.0 X 109/L was reported. Review of the peripheral blood smear (see image below) reveals single platelets in open fields as well as platelet clumps. The platelet count is likely INCORRECT.||View Page|
Smudge cells are remnants of cells that lack any identifiable cytoplasmic membrane or nuclear structure. Smudge cells, also called basket cells, are most often associated with abnormally fragile lymphocytes in disorders such as chronic lymphocytic leukemia (CLL). However, they can also be seen in degenerating samples; in which case, their origin may not be lymphocytic. Smudge cells are indicated by the arrows in this image. In some laboratories, a semi-quantitative estimate of the number of smudge cells may be made; in others, a report of "smudge cells present" may suffice. This reporting scheme must be understood by the physician in order to maximize patient care outcomes through his/her decision making process. For example, in the context of this exercise, does it make any difference to the physician if you report few or many smudge cells; or, is a report of smudge cells present sufficient? The answer to this question applies not only to smudge cells, but to the reporting of any other atypical white cells as well. An agreement must be reached between the hematology laboratory and clinical services as to how semi-quantitative estimates will impact the need for further testing in view of patient care outcomes.
The findings in the image to the right (peripheral blood smear) would elicit a report comment of "increased platelets" of a high magnitude, such as "marked" or "4+." Estimates of platelet counts from review of a peripheral blood should be made on each smear examined. This provides a simple estimate of "high", "low", or "normal" which usually corroborates the value generated from an automated cell counter. A formula for estimating platelet counts must be established for each laboratory. One guideline for the estimation of platelets is as follows: Count platelets on 5 fields using 1000X magnification (care should be taken to ensure the fields used for counting are not too thick or too thin) Average the platelet counts obtained Multiply by 15 X 109/L to obtain estimated platelet count (some laboratories prefer a 20 X 109 multiplier in this step if capillary blood is used)Such a counting scheme for platelets when clustered, as in the image, is probably not needed, as there are more than 100 platelets in the field. This translates into a platelet count of 1500 X 109/L or more.
The following pages in this presentation includes a series of white blood cell and platelet abnormalities (nonneoplastic) that may be identified in a peripheral blood smear. Many cases will simulate the practice of a peripheral smear review by a hematology technologist. He or she must assess what responses in patient care may be triggered by the clinician attempting to interpret the reported findings on a peripheral smear.Observations of white blood cell abnormalities in the peripheral blood smear should be reported in order to direct the physician to an immediate specific diagnosis, such as: Atypical lymphocytes, suggesting infectious mononucleosis rather than leukemia Toxic granules in neutrophils, as found in acute infections, or atypical granules suggesting a genetic disorder An unusual mix of cells, such as too many or too few neutrophils, monocytes, or other myeloid cells The presence of giant platelets, myelocytes, or other cells, suggesting a myelodysplastic syndromeIn summary, laboratory data should be presented to clinicians in a user-friendly fashion to promote effective decision making.
|The image on the right is a microscopic field from a Wright-Giemsa stained peripheral blood smear (1000X magnification). The structure indicated by the arrow is an artifact and should not be reported.||View Page|
|A representative field from a peripheral blood smear, seen on the right, was held for morophological and clinical review as the total platelet count was 10.0 X 109/L. Conditions fitting this picture include:||View Page|
|This image is representative of a peripheral blood smear. Some automated instruments may report this platelet count as:||View Page|
|The peripheral blood smear shown in this image was held for review because of an increase in platelets. Conditions in which platelets are increased as noted in this image include:||View Page|
|Cells that appeared similar to those illustrated in this image were repeatedly encountered as the smear was reviewed. The peripheral white blood cell count was 51.0 X 109/L with an orderly maturation sequence. The comment "leukemoid reaction" may properly be appended to the report.||View Page|
|A peripheral blood smear with many myeloid cells was presented for morphology review (see image on the right). Toxic granulation and vacuoles in the neutrophil most likely represent which of the following conditions?||View Page|
|Atypical neutrophilic intra-cytoplasmic inclusions, as noted in the image, are present in a peripheral blood smear when one or more of the following underlying conditions are present:||View Page|
|WBC inclusions: Summary|
The presence of atypical inclusions within the cytoplasm of neutrophils and other leukocytes should lead to a clinical investigation of the setting for these findings. Atypical neutrophil inclusions may be seen in the following disorders: Chediak-Higashi syndrome, May-Hegglin anomaly, Alder-Reilly anomaly, Fechtner , Sebastian, Epstein and Alport-like syndromes and in infectious and toxic conditions (in the form of Dohle bodies).Although a specific entity may not be evident from examination of the peripheral blood alone, it is important that hematology technologists include a comment reporting on the presence of these inclusions or granules. A clinical investigation with further hematologic and genetic studies may then appropriately be considered. Many of the disorders with atypical neutrophil cytoplasmic granules are also associated with platelet abnormalities, particularly giant platelets (lower image). Therefore, when atypical granules are recognized, scanning of the peripheral blood smear for atypical platelets may be revealing. These observations serve as readily identifiable markers for acquired and genetic human maladies, and as a guide for unraveling the reasons for a patient's suffering and impaired health.
|Dohle Bodies: Review||View Page|
The cytoplasm of eosinophils is evenly filled by numerous orange-red granules of uniform size. They do not overlie the nucleus. The eosinophil granules contain numerous enzymes including peroxidase, phospholipase D, catalase, acid phosphatase, and vitamin B12-binding proteins. The eosinophil's ability to kill bacteria is less than that of neutrophils. Their main purpose is to counteract parasitic infections and to participate in immune allergic reactions. They may also be increased in a variety of nonimmunologic inflammatory responses from bacteria and fungi causing chronic infections. A high percentages of eosinophils may be present in the peripheral blood smears of patients with a variety of non-neoplastic conditions including:Asthma Urticaria Loeffler syndrome Parasitic infections Malignancies, collagen vascular diseases, and myeloproliferative disorders may also may be settings for prominent eosinophils.
|A peripheral blood smear was reviewed and a representative field is shown on the right. Which of the following conditions may produce the results seen in this image?||View Page|
|The image on the right represents a peripheral blood smear field. The white blood cell seen in the image is a mast cell.||View Page|
|A peripheral blood smear is observed during a manual differental review. The patient is a 10 year-old boy with symptoms suggesting appendicitis and an appendectomy is being considered. The total WBC is 18.5 X 1000/uL, RBC's = 5.45 X 1M/uL, hemoglobin = 16.0 g/dL, hematocrit 48.2%.WBC differential:Segs = 53%, bands = 42% (two of which are shown in the image) monocytes = 2% lymphocytes= 2% These findings support the diagnosis of appendicitis.||View Page|
|The neutrophils seen in two fields in the upper and lower images are representative of a majority of the left shift neutrophils found in this peripheral blood smear. The diagnosis of Pelger-Huet anomaly can be made.||View Page|
|Case One Follow-up|
The blood count alone might be interpreted as reflecting infection, possibly supporting a diagnosis of acute appendicitis. However, the technologist performing the differential noted that more than 70% of the segmented neutrophils had bi-lobed or mono-lobed nuclei, strongly suggesting Pelger-Huet anomaly. Since the peripheral blood smear did not support the diagnosis of appendicitis in this patient, and since abdominal pain localized to the right lower quadrant never developed, the boy was hydrated with intravenous fluid and observed. After hydration, his constitutional symptoms improved and the abdominal pain subsided. People entering high altitude where the humidity may be very low are susceptible to dehydration and may experience symptoms related to mountain sickness.
|A most useful follow-up test to consider when faced with hypersegmented neutrophils and oval macrocytes (see image) in a peripheral blood smear is:||View Page|
Plasma cells are uncommonly observed in the peripheral blood smear. They are normal constituents of lymph nodes, spleen, connective tissue and bone marrow. The presence of plasma cells in the peripheral blood is indicative of a large number of conditions, mostly related to infections , immune disorders, malignancies, toxic exposures, hypersensitivity reactions and their responses.Although mature plasma cells have a distinct appearance, they still may be confused morphologically with immature plasma cells and other cells with inclusions, reactive changes or nucleated red bloods cell with altered identities. In the image to the right, a plasma cell is present. The plasma cell has an eccentric immature nucleus with a muddy chromatin pattern. Note also clumping and stacking of the erythrocytes, typical of rouleaux formation, implicating an increase in plasma gamma globulin. Further studies are in order, including a bone marrow examination, where at least 30% of bone marrow cells should be variations of mature and immature plasma cells. Serum protein electrophoresis will reveal a monoclonal globulin spike, and light chains in excess of 1.0 gm/24 hours may be seen in the urine. The presence of lytic bone lesions is a convincing clinical clue. With these findings in combination, a diagnosis of myeloma can be made with assurance.