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Encyclopedia > Blood film
Blood films, Giemsa stained
Blood films, Giemsa stained

A blood film or peripheral blood smear is a slide made from a drop of blood, that allows the cells to be examined. Blood films are usually done to investigate hematological problems (disorders of the blood itself) and, occasionally, to look for parasites within the blood such as malaria and filaria. Image File history File links Download high-resolution version (1769x1164, 1076 KB)Example of properly prepared thick and thin film blood smears to be examined (Giemsa stain). ... Image File history File links Download high-resolution version (1769x1164, 1076 KB)Example of properly prepared thick and thin film blood smears to be examined (Giemsa stain). ... A complex of stains specific for the phosphate groups of DNA. Used in Giemsa banding (or G-banding) to stain chromosomes and often used to create a karyotype. ... Microscope slides and cover slips. ... Human blood smear: a - erythrocytes; b - neutrophil; c - eosinophil; d - lymphocyte. ... Hematology is the branch of medicine that is concerned with blood and its disorders. ... A parasite is an organism that spends a significant portion of its life in or on the living tissue of a host organism and which causes harm to the host without immediately killing it. ... Malaria is an infectious disease that is widespread in tropical and subtropical regions. ... Filariasis is a parasitic and infectious tropical disease, caused by the thread-like parasitic filarial worms, Wuchereria bancrofti, Brugia malayi, and Brugia timori, all transmitted by mosquitoes. ...

Contents

Preparation

Blood films are made by placing a drop of blood on one end of a slide, and using a spreader slide to spread the blood over the slide's length. The aim is to get a region where the cells are spaced far enough apart to be counted and differentiated.


The slide is left to air dry, after which the blood is fixed to the slide by immersing it briefly in methanol. After fixation, the slide is stained, so the cells can be distinguished from each other. Look up Fixation in Wiktionary, the free dictionary. ... Methanol, also known as methyl alcohol or wood alcohol, is a chemical compound with chemical formula CH3OH. It is the simplest alcohol, and is a light, volatile, colourless, flammable, poisonous liquid with a distinctive odor that is somewhat sweeter than ethanol (ethyl alcohol). ... Staining is a biochemical technique of adding a class-specific (DNA, proteins, lipids, carbohydrates) dye to a substrate to qualify or quantify the presence of a specific compound. ...


Common blood film staining methods

Romanowsky staining was a prototypical staining technique that was the forerunner of several distinct but similar methods, including Giemsa, Wright, and Leishman stains, which are used to differentiate cells in pathologic specimens. ... Giemsa stain is used for the histopathological diagnosis of Malaria and other parasites. ... Wrights stain is a technique in histology that is used to make the differences between cells visible under light microscopy. ... Jenners Stain (methylene blue eosinate) is used in microscopy for staining blood smears. ... Leishmans stain, also Leishman stain, is used in microscopy for staining blood smears. ... Fields stain is a histological method for staining of blood smears. ...

Interpretation

Routine examination

As stated, a blood film will help identify circulating blood cells. Apart from counting the cells, morphology of cells can provide a wealth of information and assist in making a diagnosis[1]. A blood cell is any cell of any type normally found in blood. ... A full blood count (FBC) or complete blood count (CBC) is a test requested by a doctor or other medical professional that gives information about the cells in a patients blood. ... Comparative anatomy is the study of similarities and differences in organisms. ... Diagnosis (from the Greek words dia = by and gnosis = knowledge) is the process of identifying a disease by its signs, symptoms and results of various diagnostic procedures. ...


Cellular components of blood are:

Normal blood films are typically full of red blood cells, with occasional white blood cells and minuscule platelets, which are harder to notice due to their size. Human red blood cells Red blood cells are the most common type of blood cell and the vertebrate bodys principal means of delivering oxygen from the lungs or gills to body tissues via the blood. ... Human red blood cells Red blood cells are the most common type of blood cell and are the vertebrate bodys principal means of delivering oxygen to body tissues via the blood. ... To meet Wikipedias quality standards, this article may require cleanup. ... White Blood Cells is also the name of a White Stripes album. ... A 250 ml bag of newly collected platelets. ... A 250 ml bag of newly collected platelets. ... Human red blood cells Red blood cells are the most common type of blood cell and are the vertebrate bodys principal means of delivering oxygen to body tissues via the blood. ... White Blood Cells is also the name of a White Stripes album. ... A 250 ml bag of newly collected platelets. ...


Disorders

Characteristic red blood cell abnormalities are anemia, sickle cell anemia and spherocytosis. Sometimes the microscopic investigation of the red cells can be essential to the diagnosis of life-threatening disease (e.g. TTP). This article discusses the medical condition. ... Sickle-shaped red blood cells Sickle cell anemia (American English), sickle cell anaemia (British English) or sickle cell disease is a genetic disease in which red blood cells may change shape under certain circumstances. ... Spherocytosis is an auto-hemolytic anemia (a disease of the blood) characterized by the production of red blood cells that are sphere-shaped, rather than donut-shaped. ... Thrombotic thrombocytopenic purpura (TTP or Moschcowitz disease) is a rare disorder of the blood coagulation system that in most cases arises from the deficiency or inhibition of the enzyme ADAMTS13, which is responsible for cleaving large multimers of von Willebrand factor. ...


White blood cells are classified according to their propensity to stain with particular substances, the shape of the nuclei and the granular inclusions.

A microscopic view of an abnormal blood film.
A microscopic view of an abnormal blood film.
  • Neutrophil granulocytes usually make up close to 80% of the white count. They have multilobulated nuclei and lightly staining granules. They assist in destruction of foreign particles by the immune system by phagocytosis and intracellular killing.
  • Eosinophil granulocytes have granules that stain with eosin and play a role in allergy and parasitic disease. Eo's have a multilobulated nucleus.
  • Basophil granulocytes are only seen occasionally. They are polymorph-nuceated and their granules stain with alkaline stains, such as haematoxylin. They are further characterised by the fact that the granula seem to overlie the nucleus. Basophils are precursors of mast cells, the cells that mediate local allergy and immune response in organs such as the skin.
  • Lymphocytes have very little cytoplasm and a large nucleus (high NC ratio) and are responsible for antigen-specific immune functions, either by antibodies (B cell) or by direct cytotoxicity (T cell). The distinction between B and T cells cannot be made by light microscopy.
  • Plasma cells are mature B lymphocytes that engage in the production of one specific antibody. They are characterised by light basophilic staining and a very ecentric nucleus.
  • Other cells are white cell precursors. When these are very abundant it can be a feature of infection or leukemia, although the most common types of leukemia (CML and CLL) are characterised by mature cells, and have more of an abnormal appearance on light microscopy (it should be noted that additional tests can aid the diagnosis).

Blood film, captured by a friend of mine. ... Blood film, captured by a friend of mine. ... A microscope (Greek: micron = small and scopos = aim) is an instrument for viewing objects that are too small to be seen by the naked or unaided eye. ... Neutrophil granulocytes, generally referred to as neutrophils, are the most abundant type of white blood cells and form an integral part of the immune system. ... The immune system protects the body from infection by pathogenic organisms. ... Phagocytos Headline text is (literally cell-eating) is a form of endocytosis wherein large particles are enveloped by the cell membrane of a (usually larger) cell and internalized to form a phagosome, or food vacuole. ... Eosinophils are white blood cells that are responsible for combating infection by parasites in the body. ... Eosin is an orange-pink dye derived from coal tar. ... Basophil granulocyte Basophils are the least common of the granulocytes, representing about 1% of circulating leukocytes. ... Haematoxylin Haematein Haematoxylin, hematoxylin, Natural Black 1, or C.I. 75290 is extracted from the wood of the logwood tree. ... Mast cells A mast cell (or mastocyte) is a resident cell of connective tissue that contains many granules rich in histamine and heparin. ... A lymphocyte is a type of white blood cell involved in the human bodys immune system. ... Organelles. ... The eukaryotic cell nucleus. ... An antigen is a substance that stimulates an immune response, especially the production of antibodies. ... Wikipedia does not yet have an article with this exact name. ... B cells are lymphocytes that play a large role in the humoral immune response (as opposed to the cell-mediated immune response). ... Cytotoxicity is the quality of being poisonous to cells. ... T cells are a subset of lymphocytes that play a large role in the immune response. ... Plasma cells (also called plasma B cells or plasmocytes) are cells of the immune system that secrete large amounts of antibodies. ... B cells are lymphocytes that play a large role in the humoral immune response (as opposed to the cell-mediated immune response). ... Schematic of antibody binding to an antigen An antibody or immunoglobulin is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects like bacteria and viruses. ... Basophilic is a technical term used by histologists. ... The eukaryotic cell nucleus. ... A precursor is something that existed before and was incorporated into something that came later. ... An infection is the detrimental colonization of a host organism by a foreign species. ... Leukemia (or leukaemia; see spelling differences) is a cancer of the blood or bone marrow characterized by an abnormal proliferation of blood cells, usually white blood cells (leukocytes). ... Chronic myelogenous leukemia (or CML) is a form of chronic leukemia characterised by increased production of myeloid cells in the bone marrow. ... Chronic lymphocytic leukemia, or CLL, is a cancer in which too many lymphocytes (a type of white blood cells) are produced. ...

Use in diagnosing malaria

Blood smear from a P. falciparum culture (K1 strain). Several red blood cells have ring stages inside them. Close to the center there is a schizont and on the left a trophozoite.
Blood smear from a P. falciparum culture (K1 strain). Several red blood cells have ring stages inside them. Close to the center there is a schizont and on the left a trophozoite.

The preferred and most reliable diagnosis of malaria is microscopic examination of blood films, because each of the four major parasite species has distinguishing characteristics. Two sorts of blood film are traditionally used. Thin films are similar to usual blood films and allow species identification, because the parasite's appearance is best preserved in this preparation. Thick films allow the microscopist to screen a larger volume of blood and are about eleven times more sensitive than the thin film, so picking up low levels of infection is easier on the thick film, but the appearance of the parasite is much more distorted and therefore distinguishing between the different species can be much more difficult.[1] From the thick film, an experienced microscopist can detect parasite levels down to as low as 0.0000001%. Microscopic diagnosis can be difficult because the early trophozoites ("ring form") of all four species look identical and it is never possible to diagnose species on the basis of a single ring form; species identification is always based on several trophozoites. Please refer to the chapters on each parasite for their microscopic appearances: P. falciparum, P. vivax, P. ovale, P. malariae. Image File history File links Download high-resolution version (1159x745, 95 KB) I, the creator of this work, hereby release it into the public domain. ... Image File history File links Download high-resolution version (1159x745, 95 KB) I, the creator of this work, hereby release it into the public domain. ... Malaria culture is the method to grow malaria parasites continuously in an in vitro environment. ... Binomial name Plasmodium falciparum Welch, 1897 Plasmodium falciparum is a protozoan parasite, one of the species of Plasmodium that cause malaria in humans. ... Binomial name Plasmodium vivax Grassi & Feletti 1890 The parasite Plasmodium vivax is the most frequent and widely distributed cause of benign, but recurring (tertian), malaria. ... Binomial name Plasmodium ovale , Plasmodium ovale is a species of parasitic protozoa that causes benign tertian malaria in humans. ... Binomial name Plasmodium malariae Feletti & Grassi, 1889 Plasmodium malariae is a parasitic protozoa that causes malaria in humans. ...


The biggest pitfall in most laboratories in developed countries is leaving too great a delay between taking the blood sample and making the blood films. As blood cools to room temperature, male gametocytes will divide and release microgametes: these are long sinuous filamentous structures that can be mistaken for organisms such as Borrelia. If the blood is kept at warmer temperatures, schizonts will rupture and merozoites invading erythrocytes will mistakenly give the appearance of the accolé form of P. falciparum. If P. vivax or P. ovale is left for several hours in EDTA, the build up of acid in the sample will cause the parasitised erythrocytes to shrink and the parasite will roll up, simulating the appearance of P. malariae. This problem is made worse if anticoagulants such as heparin or citrate are used. The anticoagulant that causes the least problems is EDTA. Romanovski's stain or a variant stain is usually used. Some laboratories mistakenly use the same stain as they do for routine haematology blood films (pH 7.2): malaria blood films must be stained at pH 6.8, or Schüffner's dots and James's dots will not be seen. An anticoagulant is a substance that prevents coagulation; that is, it stops blood from clotting. ... Heparin is a highly sulfated glycosaminoglycan widely used as an injectable anticoagulant. ... Chemical strucutre of citric acid. ... EDTA is the chemical compound ethylenediaminetetraacetic acid. ... Staining is a biochemical technique of adding a class-specific (DNA, proteins, lipids, carbohydrates) dye to a substrate to qualify or quantify the presence of a specific compound. ... pH is a measure of the acidity of a solution in terms of activity of hydrogen (H+). For dilute solutions, however, it is convenient to substitute the activity of the hydrogen ions with the molarity (mol/L) of the hydrogen ions (however, this is not necessarily accurate at higher concentrations...


Reference

  • [2] Bain BJ. Diagnosis from the Blood Smear. N Engl J Med 2005;353:498-507. PMID 16079373.

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Reference.com/Encyclopedia/Blood film (841 words)
Blood films are usually done to investigate hematological problems (disorders of the blood itself) and, occasionally, to look for parasites within the blood such as malaria and filaria.
Blood films are made by placing a drop of blood on one end of a slide, and using a spreader slide to disperse the blood over the slide's length.
Normal blood films are typically full of red blood cells, with occasional white blood cells and minuscule platelets, which are harder to notice due to their size.
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