Leukocyte Information and Courses from MediaLab, Inc.
These are the MediaLab courses that cover Leukocyte and links to relevant pages within the course.
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| Turbidity Spinal fluid samples are either clear or turbid. Some sources use the following rating system for turbid CSF specimens: 0 = crystal clear fluid 1+ = faintly cloudy, smoky, or hazy 2+ = turbidity clearly visible but newsprint read easily through tube 3+ = newsprint not easily read through tube 4+ = newsprint cannot be seen through the tubeTurbidity may be caused by leukocytes, erythrocytes, fungi, bacteria, amoebae, contrast media, or aspiration of epidural fat during puncture.200 leukocytes/mm3 will cause slight turbidity (1+); increased numbers of WBCs will cause increased turbidity. At least 400 erythrocytes/mm3 are needed to produce 1+ turbidity.Occasionally CSF will have an oily appearance due to the presence of substances remaining in the CSF after radiologic (x-ray) procedures have been performed. | View Page |
| Normal Cell Counts Up to 5 WBCs per microliter are present in normal adult CSF.
Children have slightly higher counts, while in newborns a count of up to 30 leukocytes per microliter is within normal limits.
CSF containing up to 200 WBCs or 400 RBCs per microliter may appear clear or only slightly hazy, so all specimens must be examined microscopically. | View Page |
| Examining CSF with the Hemacytometer Specimens that are clear may be counted undiluted as long as there is no overlapping of the cells. Examining an undiluted CSF involves the following steps:
Mix the CSF manually 6 - 10 times or place it in a mechanical mixer for 5 minutes.Using a Pasteur pipet or Dispo® pipet, fill both sides of the hemacytometer and allow the cells to settle for 5 minutes. To prevent the fluid in the chamber from evaporating, place it in a Petri dish containing moist filter paper. A disposable chamber similar to a hemacytometer is preferred, if one is available.Focus on low power (10x) and scan for the presence of cells. If cells are located, switch to high power (40x) to determine whether the cells are leukocytes or erythrocytes. Erythrocytes will be smooth refractile discs or spheres. Some red cells may appear crenated. Keep in mind that some red cells may be folded or in a vertical position rather than flat. In this situation only a small portion of the cell will be visible. | View Page |
| Which of the following tests included on a urine reagent strip would never be reported out as negative? | View Page |
| Which of the following white blood cells would NOT produce a positive leukocyte esterase test? | View Page |
| A voided urine specimen is delivered from the women's clinic to the laboratory six hours after collection. The following results are reported: Color: yellowProtein: negativeBilirubin: negative Clarity: cloudyGlucose: negativeUrobilinogen: 0.2 mg/dL Sp. Gravity: 1.020Ketone: negativeNitrite: positive pH: 9.0Blood: negativeLeukocyte esterase: negativeWhat might these results indicate? | View Page |
| Procedure Caution Although the procedure is simple to perform, accurate results depend on careful adherence to manufacturer’s directions and adequate quality control. Normal and abnormal controls should be tested whenever a new lot of strips is opened, and at the frequency defined by the laboratory's procedure. If quality control results do not correspond to the published control values, the problem must be resolved before patient samples are tested. High levels of ascorbic acid (Vitamin C) in the urine may inhibit some reagent strip reactions, such as glucose, blood, bilirubin, nitrate and leukocyte esterase. The urine dipstick's package insert will provide information about potential interfering substances, including ascorbic acid. Intensely colored urine may make it difficult to correctly interpret color reactions on the dipstick. The affected tests should not be reported from the dipstick. It would be necessary to use an alternative method of testing if available. | View Page |
| Leukocyte Esterase Dipstick Test If leukocyte esterase is detected, a color change occurs on the reagent pad after the strip is dipped in the urine sample. Be sure to follow the manufacturer's directions for read-time and test interpretation. A positive leukocyte esterase test indicates the presence of granulocytic white blood cells. Lymphocytes do not contain granules, and would not produce a positive leukocyte esterase test. Positive results should be confirmed by performing a microscopic examination on the sediment; being aware that white blood cells may be absent if they are lysed, yet releasing their esterases into the specimen. Positive results may occasionally be found in random specimens from females due to contamination of the specimen by vaginal discharge. | View Page |
| False Positive Leukocyte Esterase Test A false positive result may occur in the presence of strong oxidizing agents in the collection container. In random urine specimens from women, a positive result for leukocyte esterase may be due to a source external to the urinary tract. Other urine sediment findings such as bacteria, squamous or renal epithelial cells, lymphocytes or red blood cells do not contain esterases, and would not produce a positive leukocyte esterase test. | View Page |
| A positive leukocyte esterase test indicates the presence in a urine specimen of which of the following? | View Page |
| False-negative results on reagent strips for leukocytes may occur when the specimen contains: (Choose ALL of the correct answers) | View Page |
| To screen for urinary tract infections leukocyte esterase should be coupled with: (Choose ALL of the correct answers) | View Page |
| Which of the following is most commonly associated with febrile non-hemolytic transfusion reactions: | View Page |
| Patients with which of the following conditions would benefit most from washed red cells: | View Page |
| Antibodies to which of the following are the most frequent cause of febrile transfusion reactions: | View Page |
| The cells present in this illustration are: | View Page |
| Identify the urine sediment elements shown by the arrow: | View Page |
| Identify the leukocyte seen in this illustration: | View Page |
| Pluripotential stem cells are capable of producing which of the following: | View Page |
| Which of the following formulas would you use to calculate absolute cell counts | View Page |
| The procedure which may be used to assist in differentiating chronic myelocytic leukemia from leukemoid reaction is: | View Page |
| Which of the following may interfere with the accurate measurement of hemoglobin: | View Page |
| This smear technique has the advantage of providing the best WBC distribution when performed correctly: | View Page |
| Match functions with cell: | View Page |
| A 25 year-old female presented in the emergency room with an acute urethral discharge of 2 days duration. A smear for gram stain was obtained (see accompanying image). Many polymorphonuclear leukocytes and intracellular and extracellular gram negative diplococci were observed.
Based on the clinical history and the gram stain observation, a diagnosis of gonorrhea can be made. | View Page |
| Review 2 Tuomanen EI.:
Pathogenesis of pneumococcal inflammation: otitis media
Vaccine. 19 Suppl 1:S38-40, 2000Pneumococci cause damage to the ear in otitis media with an association with bacterial meningitis. The pathogenesis of injury involves host response to cell wall constituents and the pore-forming toxin, pneumolysin.Release of cell wall constituents, particularly during antibiotic-induced bacterial lysis, leads to an influx of leukocytes and subsequent tissue injury. The signal transduction cascade for this response is becoming defined and includes CD14, Toll-like receptor 2, NFkB, and cytokine production.The second source of injury is the cytotoxicity of the pore forming toxin, pneumolysin.Decreasing the sequelae of otitis can be achieved by an increased understanding of the site-specific mechanisms of pneumococcal-induced inflammation. | View Page |
| Middle ear damage in cases of S. pneumoniae infections are caused primarily by: | View Page |
| Each of the following is related to the virulence of Listeria monocytogenes except: | View Page |
| The peripheral blood leukocyte count in this patient will likely be: | View Page |
| Which type of leukocyte, other than a neutrophil, has digestive enzymes within its granules and is phagocytic in tissues? | View Page |
| Please identify the illustrated leukocyte. | View Page |
| Please identify the illustrated leukocyte. | View Page |
| Please identify the illustrated leukocyte. | View Page |
| Please identify the illustrated leukocyte. | View Page |
| Please identify the illustrated leukocyte. | View Page |
| Leukocytes or White Blood Cells (WBC's) The second group of cells are the leukocytes or white blood cells (WBC's). The leukocytes can be divided into two groups: granulocytes and mononuclear cells. Leukocytes are involved in various ways with the body's defense mechanisms. The cell shown by the red arrow is a mononuclear cell, in this case a monocyte. The cell shown by the blue arrow is a granulocyte, in this case a neutrophil. These cells will be presented in much more detail later. | View Page |
| Glossary of Terms A through M. Antibody - A modified type of serum globulin synthesized by lymphoid tissue in response to antigenic stimulus. By virtue of specific combining sites each antibody reacts with only one antigen. Anucleate - Having no nucleus. Azurophilic granules - The well-defined large reddish granules (lysosomes) which may be present in large lymphocytes. They are called "azurophilic granules" because they stain blue with the azure stains which were originally used. Basophilic granules - Specific granules present in the cytoplasm of basophils. These granules are large and stain purple-black due to their strong affinity for basic stain. B-cell - Bone marrow derived lymphocytes which produce humoral antibodies. Biconcave - Having two concave surfaces. Cellular Immunity - The capacity of a small proportion of lymphoid population to exhibit response to a specific antigen. Chromomere - The centrally located granular portion of the platelet. Clone - A population of cells descended from a single cell. Delayed Hypersensitivity - (part of cellular immunity) that develops slowly over a period of 24-72 hours after an antigenic stimulus. It consists of an accumulation of cells around small vessels and/or nerves. Example: Tuberculin skin test reaction. Digestive Enzyme - A substance that catalyzes or accelerates the process of digestion. Eosinophilic Granules - Specific granules present in the cytoplasm of eosinophils. These granules are large, refractile spheres which stain reddish-orange due to their strong affinity for acid stain. Erythrocyte (red blood cell, RBC) - One of the elements found in peripheral blood. Normally the mature form is a non-nucleated, circular, biconcave disk adapted to transport respiratory gases. Fixed Macrophage - A phagocyte that is non-motile. Free Macrophage - An ameboid phagocyte present at the site of inflammation. Graft Rejection - A transplanted tissue that is rejected by the body's antibodies. Graft vs. Host Reaction - A complication that occurs when an implanted piece of tissue, which contains antibodies, rejects the host's tissue. Granulocyte - A leukocyte which contains granules in its cytoplasm, i.e., neutrophilic, eosinophilic, or basophilic granules. Half-life - is the length of time it takes for half of the cells circulating at a given time to leave the blood for the tissues. Hemocyte - Any blood cell or formed element of the blood. Hemostasis - A mechanism of the vascular system to arrest an escape of blood. It involves an interaction between blood vessels, platelets, and coagulation. Heparin - A mucopolysaccharide acid which, when present in sufficient amounts, functions as an anticoagulant by inhibiting thrombin. Histamine - A powerful dilator of capillaries and a stimulator of gastric secretions. Humoral Immunity - Acquired immunity produced after response to an antigenic stimulus in which B cells produce circulating antibodies. Hyalomere - the clear, blue non-granular zone surrounding the chromomere of a platelet. Immune Response - The interaction of a cell and an antigen that results in a proliferation of the cell and a capacity to produce antibodies. Isotonic Fluid - A fluid whose elements have an equal osmotic pressure. Leukocyte (white blood cell, WBC) - One of the formed elements of the blood; involved primarily with the body's defense. Lysosome - A microscopic body within cell cytoplasm; contains various enzymes, mainly hydrolytic, which are released upon injury to the cell. Megakaryocyte - A giant cell of the bone marrow from which platelets are derived. Mononuclear - A cell having a single nucleus. | View Page |
| Segmented Neutrophil Segmented Neutrophil is also be referred to as seg, polymorphonuclear leukocyte, poly and PMN. Segmented neutrophils are the most mature neutrophilic granulocytes present in circulating blood. Their diameter is approximately 9-15 microns, and their N:C ratio is 3:1. | View Page |
| Mononuclear Cells: Lymphocytes and Monocytes. The mononuclear leukocytes consist of two cell types: lymphocytes and monocytes. In contrast to the granulocytes, these cells have rounded nuclei, some with indentations or folds. Granules are not prominent. | View Page |
| Monocytes Nucleus compared to other Leukocytes Monocytes have generally lighter staining nuclei than do other leukocytes. The nucleus stains a pale bluish-violet, and the chromatin is fine and skein-like. | View Page |
| White blood cells Leukocytes, or white blood cells, help the body fight infections.
Leukocytes are shown in the photomicrograph of the stained blood smear to the right.
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| Cellular elements The gram stain reaction and appearance can be used to identify most cellular material seen in a direct smear. Identification of cellular elements present in a direct clinical smear is important because most of these elements play an important role in the disease process. For example, the quality of a sputum sample can be assessed by determining the relative numbers of squamous epithelial cells and polymorphonuclear leukocytes (segmented neutrophils) present.
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| White cells in semen Round cells in semen are of two types: immature sperm and white blood cells. To determine the percentage of white blood cells (specifically granulocytes) a special leukocyte screening test must be done. This test involves staining for the peroxidase enzyme present in the granulocytes.The 1999 WHO manual contains a protocol for doing this test (Appendix III). There is also at least one test kit on the market for this assessment (Leukoscreen: Bioscreen, Inc.).Laboratories with particular expertise in doing CBC and assessing granulocytes in stained blood smears may be able to do a differential count by this method rather than using a biochemical test for leukocyte screening. | View Page |
| White Cell Casts White cell casts appear as clear cylinders containing leukocytes. They are associated with infection or inflammation of the nephron. | View Page |
| Abnormal granulation can be seen in the cytoplasm leukocytes in which of the following conditions: | View Page |
| Typical cells on a peripheral blood smear as photographed here were repeatedly encountered as the smear was reviewed. The peripheral white blood cell count was 51,000/ml with an orderly maturation sequence. The comment "leukemoid reaction" may properly be appended to the report. | View Page |
| Familial disorders: summary Several additional familial and congenital disorders associated with atypical inclusions in WBCs are now recorded. These individual syndromes carry the following names: Fechtner, Alport, Epstein, Sebastian, and Paris-Trousseau.Fechtner syndrome( Peterson etal,Blood 65:397-406,1985)was described with 8 family members spanning 4 generations presenting with varying degrees of nephritis, deafness,and congenital cataracts. The syndrome is likely a variant of Alport syndrome with the addition of leukocyte inclusions and macrocytothemia. Several more cases involving other families have been reported. The inclusions resemble toxic Doehle bodies or those of the May-Hegglin anomaly by light microscopy, but are ultrastructurally unique.Alport syndrome in itself is autosomal dominant, X-linked , hereditary and characterized by sensorineural deafness and hereditary nephritis. It is believed to result from abnormal glycopeptide synthesis in renal basement membranes. Recurrent hematuria and slowly progressive renal insufficiency are clinical findings. Cataracts and platelet abnormalities may be added features.Epstein syndrome is essentially Alport syndrome with the addition of macrothrombocytopenia (Seri, et al. Hum Genet 110:182-186, 2002). Neutrophil inclusions are absent in this disorder; neutrophilic inclusions are considered part of the Fechtner syndrome. The Sebastian platelet syndrome is a variant of hereditary macrothrombocytopenia combined with neutrophil inclusions that differ from Doehle bodies, but are similar to those inclusions in Fechtner syndrome. (Greinacher, et al, Blut 61:282-288, 1990).Paris-Trousseau syndrome includes large platelets containing giant alpha granules identifiable in the peripheral blood.(Breton-Gorius, Blood 85:1805,1995) | View Page |
| Alder- Reilly Anomaly Large inclusions in leukocyte cytoplasm appear with Alder-Reilly syndrome. Inheritance patterns are not completely clear. The condition is characterized by larger than usual azurophilic and deeply violet staining granules clustered throughout the cytoplasm (even covering the nucleus)in all granulocytes. There are variations in which some lymphocytes and monocytes may be affected. These inclusions represent partially degraded mucopolysaccharides within lysosomes.Alder-Reilly bodies may be found independently of genetic mucopolysaccharidoses as an inherited anomaly (Jordan's anomaly). Cytoplasmic vacuoles of toxic origin are not present in Alder-Reilly cells. The background condition in Alder-Reilly syndrome is mucopolysaccharidosis with various types of bone and cartilage disorders, reported first in gargoylism, then in Hunter and Hurler syndromes. Accompanying conditions are hepatosplenomegaly, corneal opacities, and mental retardation. Reference: Brunning, Richard D. Morphologic Alterations in Nucleated Blood and Marrow Cells in Genetic Disorders. Human Pathol: 99-124, March, 1970 | 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 Doehle 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 photograph).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. | View Page |
| A most useful follow-up test to consider when faced with hypersegmented neutrophils and oval macrocytes (see photograph) in a peripheral blood smear is: | View Page |