This fluorescent test which is done analysing 60ul of blood, by centrifuging the sample in a capillary tube coated with acridine orange is. The aim of our study is to determine the sensitivity and the specificity of the qbc tube method in the detection of malaria parasite in a hospital and field setting. Quantitative buffy coat qbc test for rapid diagnosis of. Malaria is a major international public health problem. Here we report our experiences and make a comparison between the different diagnostic. Previousstudies in ethiopia 2, the philippines 3, thailand 4, and indonesia 5 concerned mainly falciparum malaria or mixed infections of falciparum and vivax malaria. The qbc malaria tube is internally coated with all the necessary reagents and anticoagulants to perform a malaria test in minutes. Delay in diagnosis and treatment is a leading cause of death in malaria patients in the united. It is important to note that the basesalt conversions. Diagnosis all plasmodium species are identified and quantified in the qbc malaria tube using the qbc paralens advance system or traditional microscope.
Because results cannot be used to speciate plasmodium, a thin smear must be examined. Understand the transmission and life cycle of malaria parasites. It involves staining of the centrifuged and compressed red cell layer with acridine orange and its examination under uv light source. In the first place, sensitivity and specificity was measured in.
The qbc autoread plus haematology system can change the way you collect and analyse samples. A qbc test is highly specific and a negative result will enable the patient to avoid a multidrug therapy. Rapid diagnosis of malaria is important for the administration of effective treatment, to reduce the morbidity and mortality. It is prevalent in endemic areas in the middle east, asia, oceania and central and south america. Pdf quantitative buffy coat analysis was used in practical diagnosis situations. This speed improvement allows users to increase lab throughput and make the most of their limited resources. The qbc malaria tube contains a fluorochrome called acridine orange and anticoagulants when a capillary or venous blood sample is added, a precision engineered plastic float is inserted into the qbc malaria tube. The test, which is an antigen capture test detecting trophozoitederived histidine rich proteinii, is simple to perform and provides a definitive answer in about 10 min. Department of immunology and parasitology, armed forces research institute of medical sciences, bangkok 10400, thailand. The flow charts in different settings for diagnosis and drug selection for the treatment of malaria are as under. The qbc malaria test is a fluorescence microscopybased malaria diagnostic test. Pdf evaluation of falcivax against quantitative buffy. Malaria should be considered a potential medical emergency and should be treated accordingly.
Plasmodium malariae and plasmodium falciparum, which do not cause relapses. Buffy coat qbc test and rapid diagnostic tests rdts are widely used and more sensitive in detecting malaria parasite. Lot of articles written on qbc malaria test and about the sensitivity. The type of medications that are used to treat malaria depends on the severity of the disease and the likelihood of chloroquine resistance. Malaria in equatorial guinea remains a major public health problem. The quantitative buffy coat qbc is a technique that is as sensitive as thick smears. Performance of the now malaria rapid diagnostic test with.
Malaria pocket guide includes information to help service personnel. Microscopy is the most widely used laboratorybased diagnostic test for malaria, and it likely will remain the test of choice for some time. These parasites are primarily spread by the bite of infected female anopheles mosquitos. The most economic, preferred, and reliable diagnosis of malaria is microscopic examination of blood films because each of the four major parasite species has distinguishing characteristics. Recently, many new rapid diagnostic tests like quantitative buffy coat qbc. Plasmodium infections were identified with a genusspecific primer set, and species differentiation between plasmodium falciparum and plasmodium vivax was analyzed by multiplex pcr. Malaria can be diagnosed by demonstration of the parasitering form,schizonts,gametocytes etc from the peripheral blood film and detection of antigen by imm. While malaria is found in more than 87 countries, most infections and deaths happen in africa.
Even microscopic diagnosis has gone through a paradigm shift with the development of new techniques such as the quantitative buffy coat qbc method and the partec rapid malaria test. A rapid procedure for the diagnosis of malaria infections directly from dried blood spots by pcr amplification was evaluated with samples from 52 patients. In contrast to other techniques for malaria diagnosis, such as the thick slide, pcr noor et al. There are four main types of plasmodium p species that infect humans plasmodium vivax and plasmodium ovale, which cause a relapsing form of the disease, and. Actal artemisininbased combination therapy artemether lumefantrine. Fluorescent stain the qbc malaria test is internally coated with fluorescent acridine orange ao stain to improve. Endemic malaria, population movements, and travelers all contribute to presenting the laboratory with diagnostic problems for which it may have little expertise available. The present study was carried out to compare the efficacy of quantitative buffy coat qbc and rapid diagnostic test rdt with conventional peripheral blood smears. The quantative buffy coat qbc is an acridine orange fluorescence staining method, used as a preliminary screening tool for the diagnosis of malaria. Detection of circulating malariaspecific antigens using rapid diagnostic test rdt, or detection of species specific parasite dna in a sample of peripheral blood using a clia validated polymerase chain reaction test pcr, or detection of malaria parasites in thick or thin peripheral blood films with report of percent parasitemia. More sensitive than giemsa thick films, it can detect as little as one parasite per l of blood and establish diagnosis earlier than thick film in 47% of low parasitemia 10 parasites per l cases. Blood samples from 100 patients were obtained with symptoms suggestive of malaria. Quantitative buffy coat is another direct and rapid test for diagnosis of malaria.
Comparative study of peripheral blood microbiology section. With centrifugation, parasites are concentrated at a predictable location. Detection and species determination of malaria parasites. Quantitative buffy coat qbc test 1,3 the qbc test is a new method for identifying the malarial parasite in the peripheral blood. In africa, it is rare except in the horn and it is almost. Microscopy has been the gold standard for malaria diagnosis for decades. The country is a holoendemic area with a yearround transmission pattern. Pdf application and evaluation of qbc malaria diagnosis in a. Malaria chapter 4 2020 yellow book travelers health.
Multiplex realtime pcr for diagnosing malaria in a non. What is the role of the quantitative buffy coat qbc. Persuade commanders to enforce malaria preventive measures. The qbc malaria test is a fluorescence microscopybased malaria diagnostic test embraced by users around the world.
Almost a decade ago our diagnostic laboratory implemented an inhouse realtime pcr for the detection of plasmodium dna to diagnose malaria in parallel with conventional diagnostics, i. Summary malaria presents a diagnostic challenge to laboratories in most countries. Malaria treatment table can be used as a guide for treatment of malaria in the united states. The qbc malaria test can provide results in just eight 8 minutes, compared to 45 minutes to 2 hours with giemsa thick films. Species differentiation is possible in the qbc malaria test. In this technique, two drops of blood, typically obtained from a finger pricked by a metal lancet, are placed on a glass microscope slide. A total of 387 samples were collected from patients presenting with fever and chills.
Rapid diagnostic tests for malaria parasites clinical. Malaria diagnosis by quantitative buffy coat technique. Evaluation of falcivax against quantitative buffy coat qbc for the diagnosis of malaria. Drug resistance and genetic variation has altered many accepted morphological appearances of malaria species, and new technology has. Comparative evaluation of a rapid diagnostic test, an. Drug resistance in malaria world health organization. Advantages to qbc are that less training is required to operate the system than for reading giemsastained blood films, and the test is typically quicker to perform than normal light microscopy.
Malaria is an infectious disease caused by plasmodium parasites. According to the manufacturer, qbc malaria test is 5. It speeds and simplifies malaria detection, with a. The purpose of this study was to determine the prevalence of malaria parasitaemia in blood donors in buea, cameroon, and to evaluate the performance of a rapid diagnostic test rdt, a malaria antibody enzymelinked immunosorbent assay elisa, and a plasmodium lactate dehydrogenase pldh elisa in the detection of asymptomatic malaria. It is based on acridine orange staining of centrifuged peripheral. The drug or drug combination recommended for each specific situation are listed in bold on the first line of each box in the adult and pediatric dosing columns. Treatment malaria is treated with antimalarial drugs and measures to control symptoms, including medications to control fever, antiseizure medications when needed, fluids and electrolytes. Malaria was diagnosed in 60, 72 and 56 patients by leishman staining technique, qbc method and malaria antigen test respectively. Learn about the different types of tests doctors use to test for malaria in your body and how the exam is performed. Thin films are similar to usual blood films and allow species identification because the parasites appearance is best preserved in this preparation. Evaluation of blood smears, quantitative buffy coat and. Moreover, the qbctechnique hasthe advantage ofspeed, and its sensitivity and specificity are good when comparedwith the gtfmethod. The qbc malaria tube contains a fluorochrome called acridine orange and anticoagulants when a capillary or venous blood sample is added, a precisionengineered plastic float is inserted into the qbc malaria tube. Rapid diagnostic tests for malaria parasites clinical microbiology.
Laboratory diagnosis of malariavarious method and its. For full access to this pdf, sign in to an existing account, or purchase an annual subscription. If we dont do the test and the doctor gives us drugs, the sickness may not stop because it may be due to other ailments and not malaria alone. Respondent 01, fgd 4 the test can identify any cause of sickness.
However, the microscope is a key tool in the integrated management of disease in resource poor settings, and the optimal role and conditions in malaria patients, a prompt and accurate diagnosis is the key. Practical uses of acridine orange fluorescence microscopy of centrifuged blood qbc malaria test tm and the qbcii hematology system tm in patients attending malaria clinics in thailand. Rapid mp qbc blood preparation, procedure, cost, normal. Command responsibility malaria control depends on directed discipline by those in. Laboratory diagnosis of malaria by conventional peripheral blood. Malaria must be recognized promptly in order to treat the patient in time and to prevent further spread of infection in the community via local mosquitoes. Compared with the qbc test and thin blood films, the now malaria test had sensitivity and specificity values of 96. The qbc tubes are internally coated with all the necessary reagents including acridine orange fluorochrome stain and anticoagulants with the exception of the qbc venous tubes. The qbc technique has been shown to be a rapid and sensitive test for diagnosing malaria in numerous laboratories settings 15,3235.
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