Smears must be prepared from anticoagulated blood within one hour after venipuncture. So theres a few different tests we can do to diagnose malaria, but ill just describe the two most common ways. Patients admitted to the icu can be counted by origin of the request for malaria testing. In nigeria, for instance, more than half of the population belongs to blood group o, which protects against malaria, wahlgren stated in a press release. Malaria from the italian mal aria, meaning bad air is an acute and sometimes chronic bloodstream infection characterized by fever, anemia and splenomegaly, caused by apicomplexan parasites of the genus plasmodium. If you are using venous blood, blood smears should be prepared as soon as. Parts of a malaria parasite inside a red blood cell.
The video describes the preparation and interpretation of a malarial thin smear for the detection of malarial parasites. Microscopy of thick blood films is the usual diagnostic test for plasmodium falciparum malaria. The small dots scattered around are due to schizonts typical of p. Nov 08, 2006 thick blood films are routinely used to diagnose plasmodium falciparum malaria. After drying, the spot is stained with diluted giemsa 1. Bring a clean spreader slide, held at a 45 angle, toward the drop of blood on the specimen slide. Does the practice of blood film microscopy for detection and.
A thick blood smear is a drop of blood on a glass slide. An easy, reliable rapid diagnostic test rdt with high sensitivity and negative predictive value npv, particularly for plasmodium falciparum, would be clinically useful. Purpose and scope to describe the recommended procedure for labelling malaria blood films this procedure is to be modified only with the approval of the national coordinator for quality assurance of malaria microscopy. However, malaria parasites may be missed on a thin blood film when there is a low parasitaemia. Screening blood donors involved in cases of transfusioninduced malaria when the donors parasitemia may be below the detectable level of blood film examination testing a patient, usually from an endemic area, who has had repeated or chronic malaria infections for a condition known as tropical splenomegaly syndrome.
Blood smear of malaria positive blood mostly science. Where the blood film is negative, at least two further films should be obtained over the subsequent 48 hours, before excluding the diagnosis. Plasmodium falciparum infection carries a poor prognosis with a high mortality if untreated, but it has an excellent prognosis if diagnosed early and treated appropriately. Diagnostic performance of rapid diagnostic tests versus blood. Importantly, having demonstrated the ways type o blood protects against severe malaria, this explains why the blood type is so common in areas where malaria is common. The giemsa stain highlights not only the malaria parasites but also the white blood cells, platelets, and artefacts.
The morphology of parasitic forms and the erythrocytes become atypical after that time from direct action of the anticoagulant. Screening blood donors involved in cases of transfusioninduced malaria when the donors parasitemia may be below the detectable level of blood film examination. If there is potential for delay, refer the patient to hospital for testing. If one test is negative and no parasites are found, you will have repeated blood. During this period, malaria diagnostic microscopy and parasitaemia evaluation have remained unchanged. The frequency with which blood films were positive at given parasite densities measured. Thick blood film examination for plasmodium falciparum malaria has. Thick and thin blood films were examined from ten patients with p. To prepare a thick blood film, a blood spot is stirred in a circular motion with the corner of the slide, taking care not make the preparation too thick, and allowed to dry without fixative. Expertlevel automated malaria diagnosis on routine blood films with deep neural networks april 14, 2020 14. Malaria is a potentially lifethreatening disease caused by infection with plasmodium protozoa transmitted by an infective female anopheles mosquito. Why type o blood protects against malaria medical daily. Areas that cannot afford laboratory diagnostic tests often use. Affordable and search from millions of royalty free images, photos and vectors.
A peripheral blood film will provide information on the following. Periodicity of fever correlates with type of malaria see table. The first is the use of reagent strips, which are impregnated with molecules that bind to various other proteins present in the blood during a malaria infection. This is the most specific, the most definitive way of diagnosing malaria and it is a couple of lab tests. Examination of thick blood films for malaria parasites. The simplest and surest test is the timehonoured peripheral smear study for malarial parasites. Therefore, this test should not be used as a primary screening test for malaria, except for clients in the immediate rochester, minnesota area when the specimen can be delivered within several hours of collection. Thick blood films are routinely used to diagnose plasmodium falciparum malaria. The simplest and surest test is the timehonoured peripheral smear study for malarial.
Malaria parasites can be identified by examining under the microscope a drop of the patients blood, spread out as a blood smear on a microscope slide. Peripheral smear study for malarial parasites the mp test. Sampling immediately upon onset of fever is the most desirable time to obtain blood. Blood smear microscopy has been used to detect malaria parasites in the blood of infected patients since laveran first identified the parasites in 1880. A thin blood smear, also called a blood film, is one drop of blood spread across most of the slide. Light microscopy of thick and thin stained blood smears remains the standard method for. Examination of giemsastained peripheral blood smear is the standard test for the diagnosis of malarial infection. A young girl informs her father shes been kidnapped and asks him to bring the ransom money. With a thick blood film, the red cells are approximately 6 20 layers thick which results in a larger volume of blood being examined. You may need to look quite carefully before you see them. Fullyautomated patientlevel malaria assessment on field.
Doctors use thick and thin blood smears to determine whether you have malaria. Testing a patient, usually from an endemic area, who has had repeated or chronic malaria infections for a condition known as tropical splenomegaly syndrome. The first difference is obvious as soon as you look at a thick film with the x 100 oil immersion objective and the x 7 ocular. Detection of unspeciated malaria parasite by microscopy on blood films in a laboratory with appropriate expertise in any person symptomatic or asymptomatic diagnosed in the united states, regardless of whether the person experienced previous episodes of malaria while outside the country. The frequency with which blood films were positive at given parasite densities measured by pcr were analysed. Any inclusion bodies eg, howelljolly bodies or malarial parasites will also be noted. Thin blood smears helps to discover which species of parasite is causing the infection. Thick and thin blood smears for malaria cs mott children.
Detection of malaria parasites in thick blood films. Older, ring stage parasites are referred to as trophozoites. The number of malaria parasites present in the blood at a given time fluctuates. Here, they were used to diagnose volunteers exposed to. Jun 05, 2018 the video describes the preparation and interpretation of a malarial thin smear for the detection of malarial parasites. Where there is suspicion of malaria, a venous blood specimen in an edta tube should be sent to the laboratory in under an hour. Thick and thin blood smear for malaria diagnosis learn. All of the developmental stages of the malaria parasite life cycle expected in the peripheral blood were observed in giemsastained thin blood films and are.
Therefore, examination of a thick blood film is recommended. Organisms are most likely to be detected just before onset of fever, which is predictable in many cases. If one test is negative and no parasites are found, you will have repeated blood smears every 8 hours for a couple of days to confirm that there is no malaria infection. Thick films contain several layers of red cells, whereas thin films contain a single layer of spread red cells. Plasmodium falciparum centers for disease control and.
Malaria parasites pass through a number of developmental stages. Thick and thin blood smears for malaria cs mott childrens. You must be able to distinguish the various parts of the parasite, as shown in the diagram that follows. Step 6 continue the examination for approximately 100 fields to determine whether the blood film is positive or negative for malaria. The mainstay of malaria diagnosis has been the microscopic examination of blood, utilizing blood films. Blood film when a peripheral blood sample is smeared on a slide and stained, it is known as a peripheral blood film peripheral blood smear.
Apr 20, 2015 blood film when a peripheral blood sample is smeared on a slide and stained, it is known as a peripheral blood film peripheral blood smear. With saed soheili, saghar ghanaat, azarakhsh farahani, azade namdari. Two kinds of blood film thick and thin are used in malaria microscopy. Thin film the thin film consists of a single layer of red blood cells and is used to assist in the identification of the malaria species, after the parasites have been seen in the thick film. Bfmp abbreviation stands for blood film for malaria parasite. Thick and thin blood smears for malaria michigan medicine. A thin film should always be examined if a definitive identification based on morphology is required. The most commonly used technique for blood examination 4. Apr 26, 2019 malaria is a potentially lifethreatening disease caused by infection with plasmodium protozoa transmitted by an infective female anopheles mosquito. Mar 09, 2015 importantly, having demonstrated the ways type o blood protects against severe malaria, this explains why the blood type is so common in areas where malaria is common. Blood film for malaria parasite how is blood film for.
The careful examination of a wellprepared and wellstained blood film currently remains the gold standard for malaria diagnosis. What is the abbreviation for blood film for malaria parasite. More recently, modern techniques utilizing antigen tests or polymerase chain reaction have been discovered, though these are not widely implemented in malaria endemic regions. The system is based on digital image analysis and featured with motorized stage units, designed to easily be mounted on most conventional light microscopes used in the endemic areas. Differences between thick blood smear and thin blood smear. Panicked, her father and brothers go to tehran to look for her. Thick blood smear for giemsa malaria microscopy, part 1 of. The number of malaria parasites in your blood can change each day. Malaria parasites take up giemsa stain in a special way in both thick and thin blood films.
Malaria parasites are rare in thin blood film images 1 per 100 rbcs in high parasitemia cases, and more commonly fewer than 1 per rbcs, so distractors typically outnumber parasites. 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. This is a video presentation on how to make a thick blood smear tbs for giemsa malaria microscopy. If doubtful diagnosis makes it necessary, more fields up to 400 may be examined. The detector needs high sensitivity, high specificity, and computational efficiency. A thin blood smear is a drop of blood that is spread across a large area of the. Diagnostic performance of rapid diagnostic tests versus. Thick blood film examination for plasmodium falciparum.
Malaria is a potentially lifethreatening disease and testing for this infection should be performed as rapidly as possible. Performance of rapid diagnostic test, blood film microscopy and pcr for the diagnosis of malaria infection among febrile children from korogwe district, tanzania. So we take some blood from the person and we stick it on a microscope slide. Parasite detection and identification for automated thin. Blood film for malaria parasite how is blood film for malaria parasite abbreviated. They are unaware, however, that the girl has in fact eloped with her boyfriend and now spends her time in the company of a band of. This paper investigates automated detection and identification of malaria parasites in images of giemsastained thin blood film specimens. In thin films the red blood cells are fixed so the morphology.
You will need to refocus, using the fine adjustment, each time you move the microscope field. They are unaware, however, that the girl has in fact eloped with her boyfriend and now spends her time in the company of a band of street. Malariababesia blood smear medical laboratory tests. Microscopic examination of blood is the most affordable, accessible, widely used and reliable technique for diagnosis of malaria infection. Performance of rapid diagnostic test, bloodfilm microscopy and pcr for the diagnosis of malaria infection. The diagnosis of malaria is frequently delayed because of the time required to prepare malaria blood films and lack of technical expertise. Differential counts and morphological characteristics of p. May 26, 2009 to prepare a thick blood film, a blood spot is stirred in a circular motion with the corner of the slide, taking care not make the preparation too thick, and allowed to dry without fixative. The poisson distribution was used to calculate the theoretical likelihood of diagnosis. Thin blood film is prepared similarly to that of the differential whitecell count. The use of both thick and thin giemsastained blood films is the gold standard method to screen for malaria parasites. Therefore, if no parasites are seen on the initial set of smears and the health practitioner still suspects malaria, then additional blood samples will be obtained to be tested.
Blood films are examined in the investigation of hematological disorders and are routinely employed to look for blood parasites, such as those of malaria and filariasis. Timing the blood smear for malaria diagnosis jama network. Although blood is the sample most frequently used to make a diagnosis, both saliva and urine have been investigated as alternative, less invasive specimens. Four species of plasmodia causing human malaria are plasmodium vivax, plasmodium falciparum, plasmodium malariae and plasmodium ovale. Blood smears are taken most often from a finger prick. Of these, 3 screen only a thick film, and 6 screen only a thin film.
Thick blood smears are most useful for detecting the presence of parasites. Blood smears, at least two thick and two thin, should be prepared as soon as possible after collection. Purpose and scope to describe the procedure for counting malaria parasites on thick and thin blood. The preferred and most reliable diagnosis of malaria is microscopic examination of blood films, because each of the four major parasite. The malaria parasites, however, can be seen, although, like the white blood cells, they appear to be smaller than in thin blood films. Density is usually assessed by thick films, either by counting parasites per microscope field, or by counting parasites per hundred white blood cells. Here, they were used to diagnose volunteers exposed to experimental malaria challenge. This work presents an automatic device for both detection and classification of malaria parasite species on thick blood film. The most commonly used microscopic tests include the peripheral smear study and the quantitative buffy coat qbc test. Capillary blood should be obtained by fingerstick, or venous blood should be obtained by venipuncture. This blood smear shows human blood positive for malaria infection, with a plasmodium falciparum gametocyte the sexual form of the most lethal of the malaria parasite species right in the center. A diagnosis of malaria should be supported by the identification of the parasites on a thin or thick blood smear. Sep 15, 2009 approximately 4 million us travelers to developing countries are ill enough to seek health care, with 1500 malaria cases reported in the united states annually. Does the practice of blood film microscopy for detection.
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