Nov 09, 2017 7 if both thick and thin are performed on the same slide in case of experienced lab technicians. The blood clot usually occurs in a persons vein, which can cause pain and affect circulation in and around the. Making and staining a blood smear university of vermont. The thin smear keeps the red blood cells intact and as moses ngeiywa.
Thick blood film examination for plasmodium falciparum. If the smear is too thick or too thin interpretation may be difficult and therefore the results from the lab may not be as useful as expected. The blood films must be laked before or during staining to rupture all the rbc so that only wbc, platelets and parasites are visualized. Since the smear is not fixed with methanol, the red blood cells rbcs lyse, permitting better visualization of the organisms. Thick and thin blood smear for malaria diagnosis learn. Scope and application this procedure describes the preparation of thick blood films. Three thick and thin smears 1224 hours apart should be obtained. Cytology pap smeargynecological specimen principle. A thin blood smear is a drop of blood that is spread across a large area of the.
The dense body of the smear takes up most of the slide and there is a thin counting area which blends with the feathered edge and the dense body. If blood does not well up, gently squeeze the finger. Thick smears require considerable experience with malaria, as they increase the number of cells. Thick blood smears are most useful for detecting the presence of parasites, because they examine a larger sample of blood. Sep 18, 2017 the conditions that result in thick blood can be inherited or acquired at a later time, as is usually the case with cancers. Then a giemsa stain 3% solution diluted with buffer for 30 minutes staining was applied on the thick film and allowed for 30 minutes. Thick films are more difficult to interpret but greatly increase sensitivity by concentrating cells and organisms.
Thick lms can be made with lower or higher volumes of blood but the diameter of the lm and the template in figure 1 below will then need to be adjusted see section 2. What is the difference between thick and thin blood smears. A blood filmor peripheral blood smearis a thin layer of blood smeared on a glass. To prepare a monolayer blood slide, follow these steps. This method produces a gradual decrease in thickness of the blood from thick to thin ends with the smear terminating in a feathered edge approximately 2 mm long. However, malaria parasites may be missed on a thin blood film when there is a low parasitaemia.
Wrap in tissue and place them, touching front to back, in a box without separating grooves. The direct microscopic visualization of the malarial parasite on the thick andor thin blood smears has been the. Images of thin blood smear were obtained from two sources, namely. The drop should be in the center line of the glass slide. Thick blood smears are most valuable for identifying the vicinity of parasites but thin blood smears are useful to find which types of parasite are bringing on the disease. What are the advantages of thin blood smear and thick. A thick blood smear is a drop of blood on a glass slide. Thick films contain several layers of red cells, whereas thin films contain a single layer of spread red cells. Is blood like your waistline the thinner, the better.
With a thick blood film, the red cells are approximately 6 20 layers thick which results in a larger volume of blood being examined. A thick blood smear is said to be a drop of blood on a glass slide whereas a thin blood smear can be defined as a drop of blood that is spread over an expansive region of the slide. The combination thickthin blood film provides both options on one glass slide and the slide can be stained as either a thick or thin blood film. The parasitemia can be calculated based on the number of infected rbcs. Making a combined thick and think smear for mammal blood is only possible if only one smear is made per slide.
Following is small sample of the many conditions that can cause thick. The thin film allows for the observation of rbc morphology, inclusions, and intracellular and extracellular parasites. The thin blood smear is prepared for studying the morphology of the blood cells and for the identification of microbial agents. Definition,differences between thick blood smear and thin. Staining procedure for thin blood film bp healthcare. Comparative study of thick smear, thin smear, qbc and. Thick smears are 20 times more sensitive than thin smears, but speciation may be more difficult. Density is usually assessed by thick films, either by counting parasites per microscope field, or by counting parasites per hundred white blood cells.
In an attempt to explain the shortcomings of the routine thick film examination in the diagnosis of scanty malaria parasitaemias, a direct comparison, in terms of positivity and parasite counts, was made between the results of routine thick film study and longterm examination of thin films taken at the same time from the same individuals. When the blood smear is totally dry, arrange the slides on the slide rack, with the blood smear facing front. Thick and thin blood smear procedure linkedin slideshare. The thick blood films are used for microscopic detection of plasmodium parasites, the causal. Delay in preparation of the smears can result in changes in parasite morphology and staining characteristics. Thick smears consist of a thick layer of dehemoglobinized lysed red blood cells rbcs. Take a single drop of blood from a mixed sample container and place to one end of a labelled clean slide. It should be of such thickness that newsprint can barely be seen through the wet or dry smear. Thick blood smear showing trypanosoma species staining the thin and thick blood smear on the same slide with giemsa stain. Remove thin smear slides and rinse by dipping 34 times in the giemsa buffer.
If fixed prior to staining, then the smear will be read as a thin blood film. Preparation of thick blood films and giemsa staining. Differences between thick blood smear and thin blood smear. Thin blood films have a low sensitivity for detection of malaria parasites. Blood films are examined in the investigation of hematological blood disorders and are routinely employed to look for blood parasites, such as those of malaria and filariasis. Thick and thin blood smears for malaria cs mott children.
Visually, the smear should appear as a round to oval smear of blood about 2 cm in diameter. Blood smears, at least two thick and two thin, should be prepared as soon as possible after col lection. Thick and thin blood smears will let doctors know the percentage of red blood cells that are infected parasite density and what type of parasites are present. Make the thin smear starting about from the nonfrosted end of the slide. Making a species identification of malarial parasites may be difficult to impossible, even for experienced technicians. Stained thick and thin blood films in research settings. The thick blood smears are prepared for detecting the blood parasites such as plasmodium spp. A thin blood smear is a drop of blood that is spread across a large area of the slide. After staining with giemsa, the slide can be examined under the microscope. The thin blood films are prepared from whole blood with clean, dry and wrapped microscope slides cfr. Thin blood smears helps to discover which species of parasite is causing the infection.
The sensitivity, specificity, positive predictive value ppv and. The unsatisfactory designation indicates that the specimen is unreliable for detection of cervical epithelial. Using the ground edge of the spreader slide spread the blood for the thin film. The thick blood film permits the examination of a large amount of blood for the presence of parasites. From the thick film, an experienced microscopist can detect all parasites they encounter. A blood filmor peripheral blood smear according to wikipediais a thin layer of blood smeared on a glass microscope slide and then stained in such a way as to allow the various blood cells to be examined microscopically.
Thick smears should be left in buffer for 5 minutes. Jul 20, 2016 video tutorial on how to perform a proper thick and thin smear for malaria diagnosis by stephane proux, malaria diagnosis lab supervisor at shoklo malaria re. While holding the spreader slide at the same angle, push it forward rapidly and smoothly. Staining thick and thin blood smears centers for disease. Wait until the blood spreads along the entire width of the spreader slide. A blood smear, thick andor thin, is run once each month or with each staining procedure if done less often than once each month. A blood film or peripheral blood smear is a thin layer of blood smeared on a glass microscope slide and then stained in such a way as to allow the various blood cells to be examined microscopically.
Thick blood smears are most valuable for identifying the vicinity of parasites but thin blood smears are useful to find which types of parasite are bringing on the. The test provides information on the number and shape of these. Second, we dont have a dipstick for checking blood viscosity. The highest yield of peripheral parasites occurs during or soon after a fever spike. If the blood is very thin severe anemia you may need to increase the angle of the spreader. Giemsa staining technique principle, preparation, procedure. Without delay, the blood was spread with a glass spreader held at a steep angle to achieve a thick smear covering an area of 15 x 15mm. Microscopy of thick blood films is the usual diagnostic test for plasmodium falciparum malaria. In an attempt to explain the shortcomings of the routine thickfilm examination in the diagnosis of scanty malaria parasitaemias, a direct comparison, in terms of positivity and parasite counts, was made between the results of routine thickfilm study and longterm examination of thin films taken at the same time from the same individuals.
A thin blood smear is usually a drop of blood that is widening over an extensive range of the slide. If one test is negative and no parasites are found, you will have repeated blood smea. Thus, for a fixed number of microscope fields, thick films allow the microscopist to examine a larger number of red cells for the presence of parasites, and low parasitaemias can be more readily identified by thick film. Sep 17, 2015 a thick blood smear is said to be a drop of blood on a glass slide whereas a thin blood smear can be defined as a drop of blood that is spread over an expansive region of the slide. April 20, 2010 acharya tankeshwar lab diagnosis of parasitic disease 1. The slides must not be in contact with each other or else the stain will be flow off.
A thin blood smear, also called a blood film, is one drop of blood spread across most of the slide. As lukasz frackowski explains, the thick smear is used to make the diagnosis of malaria as it is a concentration technique. Examination of thick blood films for malaria parasites. Thin blood smears assists specialists with discovering what types of malaria is creating the disease.
Learn about the different types of tests doctors use to test for malaria in your body and how the exam is performed. Cover each slide completely with 12ml of leishmans stain undiluted using. The thin blood film should be thick enough at the starting point 1, becoming less. A blood filmor peripheral blood smearis a thin layer of blood smeared on a glass microscope slide and then stained in such a way as to allow the various blood cells to be examined microscopically. In thin films the red blood cells are fixed so the morphology of the parasitised cells can be seen. Detection of plasmodium parasites from images of thin blood smears. Comparative study of thick smear, thin smear, qbc and antigen.
Doctors use thick and thin blood smears to determine whether you have malaria. The classic blood smear has a thumb print appearance. The well known thin smear methods of blood examination have distinct advantages for purposes of morphologic study. Blood smear make a few smears and submit the best ones to the diagnostic laboratory. The three main blood cells that the test focuses on are. Using the ground edge of the spreader slide spread the blood for the thin lm. Thick and thin blood smears for malaria cardiosmart. Good color differentiation of red and white cells is an indication of a good quality stain. For very thin cytology smears and for blood smears, 5 or 6 dips in the fixative solution should be adequate, but for thick cytology smears, up to 120 seconds may.
Procedure for thick and thin blood film staining technique. Wellmade thick blood lms are evenly spread, have 10 15 white blood cells wbcs per highpower eld hpf on average though this may vary depending on the wbc count and the eld number fn of the ocular lens at. Cells are scrapped or brushed by a qualified physician, physicians assistant, nurse, or. How to perform a proper thick and thin smear for malaria diagnosis duration. Thick and thin blood smears for malaria michigan medicine. Many dont have any symptoms of thick blood until they experience a blood clot. Therefore, examination of a thick blood film is recommended. Thick blood smears are most useful for detecting the presence of parasites. Apr 05, 2018 a thick blood smear is a drop of blood on a glass slide. This video shows the procedure for making thick and thin blood smear. Blood films are examined in the investigation of hematological blood disorders and are routinely employed to look for blood parasites, such as those of malaria and. The combination thick thin blood film is also acceptable. Whenever possible, use separate slides for thick and thin smears. Having the correct amount of blood on the slide to start with is important.
Obscuring blood, inflammation, thick areas, poor fixation, airdrying artifact, contaminant, etc. Examination of thick blood films for malaria parasites introduction the definitive diagnosis of malaria infection is still based on finding malaria parasites in blood films. Repeat with several slides at least two thick and two thin smears should be made. Preparation of thick blood films and giemsa staining projectstudy. Theres something appealing about the idea that thin, fluid blood is better for you than thick, gooey blood. The smear is greater than 25 mm long and the feathered edge stops approximately 10 mm from the end of the slide. Bring a clean spreader slide, held at a 45 angle, toward the drop of blood on the specimen slide. Make as many thin smears as possible, preferably within one hour after the blood was drawn from the patient. Thick and thin blood smears for malaria wellspan health. Comb thickthin blood film protocol medical chemical corporation. A blood smear is a blood test used to look for abnormalities in blood cells. Often there are few parasites in the blood at the time the test is done. Thick blood smear and thin blood smear differs in their definition, uses and sensitivity and these are. The combination thickthin blood film is also acceptable.
Nov 08, 2006 thick films contain several layers of red cells, whereas thin films contain a single layer of spread red cells. Thick and thin blood smears for malaria peacehealth. Preparation thin blood films and giemsa staining lqm laboratory. The blood elements including parasites, if any are more concentrated app. Pdf detection of plasmodium parasites from images of. A comparative study of thick and thin blood films in the. Allow the smears to dry quickly, using a fan or blower at room temperature. Difference between thick blood smears and thin blood smears. Thick and thin blood smears for malaria cs mott childrens. The pap smear is used to sample the female genital trac t for presence of cellular change s which may indicate cervical or uterine carcinoma or their precursors. What are the advantages of thin blood smear and thick blood. Thick blood smears are most useful for detecting the presence of parasites because they examine a larger sample of blood. The blood smear does not have to be positive for blood parasites. What is the difference between thick and thin blood smears in.
Aug 25, 2016 this video shows the procedure for making thick and thin blood smear. Prepare a thin and thick smear of the specimen on the same slide which can be done by dividing the slides into two parts and then making the thin smear on one side and thick on the other side. This was allowed to air dry in a horizontal position. How to perform a proper thick and thin smear for malaria. Plasmodium falciparum centers for disease control and. Thick and thin blood films procedure laboratory stack. Blood films are examined in the investigation of hematological blood disorders and are routinely employed to look for blood parasites, such.
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