Moreover, the qbctechnique hasthe advantage ofspeed, and its sensitivity and specificity are good when comparedwith the gtfmethod. Moreover, this technique is not reliable for very low numbers of parasites, though most active malaria infections will be positively diagnosed. So early diagnosis of malaria is very much important. Malaria can be diagnosed by demonstration of the parasitering form,schizonts,gametocytes etc from the peripheral blood film and detection of antigen by. A total of 370 cases 194 boys and 176 girls were studied giving a male.
A comparison of rapid diagnostic testing by plasmodium lactate dehydrogenase, and quantitative buffy coat technique in malaria diagnosis in children. This method involves staining parasite deoxyribonucleic acid dna in microhematocrit tubes with fluorescent dyes, e. Blood samples were collected from 364 volunteer villagers, and each sample was examined with both the qbc and gtf techniques. Detection of birefringent haemozoin has been used to diagnose malaria since the turn of the 20th. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. Prompt laboratory diagnosis of malaria is crucial for effective disease management. Previousstudies in ethiopia 2, the philippines 3, thailand 4, and indonesia 5 concerned mainly falciparum malaria or mixed infections of falciparum and vivax malaria. Rapid diagnostic tests for malaria parasites clinical. Buffy coat qbc test and rapid diagnostic tests rdts are widely used and more sensitive in. The standard diagnostic method is the microscopic examination of giemsa. The main advantages of the fast malaria stain over gs are that it is presumably less technically complex, faster to perform, can be. The aim of our study is to determine the sensitivity. Even microscopic diagnosis has gone through a paradigm shift with the development of new techniques such as the quantitative buffy coat qbc.
The renewed interest in the use of fluorochromes for malaria diagnosis prompted us to evaluate the acridine orange fluorescence technique on blood slides, and to compare it with established techniques using thick and thin blood films and the qbc malaria test, using the giemsastained thick film technique as our standard method for comparison. Malaria is one of the major causes of preventable death in the world today. The use of quantitative buffy coat qbc tubes developed for malaria diagnosis is described in the diagnosis of african trypanosomiasis. 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. An estimated 429,000 casualties were reported in 2015, with the majority made up of children under five years old. Pcr, no technique can yet be used for routine clinical automated screening. In comparison to thick smear analysis, qbc examination could be as much as 100fold more sensitive. Field evaluation of the qbc technique for rapid diagnosis of. The qbc malaria test is a fluorescence microscopybased malaria diagnostic test embraced by users around the world. The qbc technique is in common use for diagnosis of malaria, but the presence of microfilariae and trypanosomes in the bloodstream can also be effectively detected by qbc. In malaria patients, a prompt and accurate diagnosis is the key to effective disease management. Drug resistance and genetic variation has altered many accepted morphological appearances of malaria species, and new technology has given an. Summary malaria presents a diagnostic challenge to laboratories in most countries. Laboratory diagnosis of malariavarious method and its.
Delay in diagnosis and treatment is a leading cause of death in malaria patients in the united. The test uses a specially made glass capillary tube of precise internal diameter containing acridine orange as a vital stain. If not properly treated, people may have recurrences of the. The sensitivity of the qbc malaria test is particularly notable in cases of low parasitemia, as the test allows for the detection of as little as one 1 parasite per l of blood in one study of 49 patients with low parasitemia defined as 10 parasites per l of blood, the qbc test established the diagnosis earlier than thick film in 47%. However, in the last ten years, there has been a rise in the availability and effectiveness of socalled rapid diagnostic tests rdts for malaria, which can be selfadministered and so are able to be. In regions where plasmodium species are indigenous, there are multiple etiologies of fever leading to. Malaria is a mosquitoborne infectious disease that affects humans and other animals.
Malaria was diagnosed in 60, 72 and 56 patients by leishman staining technique, qbc method and malaria antigen test respectively. At the same time, several pcr assays have been developed for the diagnosis of malaria. A rapid diagnostic test rdt is an alternate way of quickly establishing the diagnosis of malaria infection by detecting specific malaria antigens in a persons blood. Alternative diagnostic methods that are timely and effective are required to identify. Laboratory diagnosis of malaria by conventional peripheral blood. They were read for 20 minutes to confirm that the qbc results were negative. At the earlystage of infection, patients show nonspecific symptoms or are asymptomatic, which makes it difficult for clinical diagnosis, especially in nonendemic areas. To extend the diagnostic possibilities, a quantitative buffy coat microscopy qbc test for rapid diagnosis of malaria can be used as well. Endemic malaria, population movements, and travelers all contribute to presenting the laboratory with diagnostic problems for which it may have little expertise available. Four diagnostic techniques for plasmodium falciparum infection were evaluated against serial parasite dilutions and on identical field samples. Rdts have recently become available in the united states. The blood film result indicated that malarial parasite was detected in 112 27. Malaria diagnosis by quantitative buffy coat technique. Comparative study of thick smear, thin smear, qbc and.
Falciparum malaria dk mendiratta, k bhutada, r narang, p narang abstract rapid diagnosis is a prerequisite for institution of effective treatment and reducing the mortality and morbidity of falciparum malaria. This technique is, in general, substantially faster than conventional microscopy by a thick smear examination, but also needs more training for appropriate reading and interpretation 7. An afford has been made to classify the tests on the bases of their specificity, sensitivity,cost effectiveness and easily availability to tertiary care center for accurate early diagnosis of malaria. Automated malaria diagnosis using pigment detection. One hundred and thirtyfour patients with trypanosoma gambiense were examined using qbc plus either haematocrit hct or mini anion exchange centrifugation maec or both. Thereference tests werethe qbcmalaria diagnosis system and by examination of thin blood smears. 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.
Acridine orange fluorescence techniques as alternatives to. Clinical diagnosis, the most widely used approach, is unreliable because the symptoms of malaria are very nonspeci. More recently, modern techniques utilizing antigen tests or polymerase chain reaction. The two diagnostic approaches currently used most often, however, do not allow a satisfactory diagnosis of malaria. This minimizes the risk of parasite resistance development, reduces drug wastage and unnecessary. Early and accurate diagnosis of malaria is of paramount importance to ensure appropriate administration of treatment. The former was performed following the recommended technique 6 and used as a screening tool. A blood specimen collected from the patient is applied to the sample pad on the test card along with certain reagents. The qbc quantitative buffy coat technique was compared with that of the giemsastained thick blood film gtf under field conditions in junlian and mingshan counties, sichuan, china, for rapid diagnosis of vivax malaria. Early diagnosis and prompt treatment is one of the main strategies in malaria prevention and control.
Comparative study of peripheral blood microbiology section. Malaria is a potentially lifethreatening disease caused by infection with plasmodium protozoa transmitted by an infective female anopheles mosquito. Comparison of quantitative buffy coat technique qbc with. Microscopic diagnosis, the established method for laboratory confir. The qbc malaria test was the first malaria diagnostic test to receive fda clearance, and. The method, which is largely used for diagnosis of malaria 15 32, was intended for rapid demonstration of amastigotes in the bm and pb of persons with avl and in dogs infected with l. After the tube is filled with blood, it is capped and a small plastic float is.
Comparative study of thick smear, thin smear, qbc and antigen. Journal of parasitology research hindawi publishing corporation. The qbc technique was designed to enhance microscopic detection of parasites and simplify malaria diagnosis 31. Every year, millions of people are burdened with malaria. The renewed interest in the use of fluorescent microscopy for malaria diagnosis prompted the comparison of quantitative buffy coat technique qbc with the old standard giemsastained thick blood film gtf in ikeja general hospital, now lagos state university teaching hospital, in lagos. Microscopic diagnosis using blood smears plays an important role in malaria diagnosis because of its ability to diagnose and differentiate each species of malaria, and so it is used as the gold standard for any new detection tool or technique see, for example, 1822. The country is a holoendemic area with a yearround transmission pattern. Field evaluation of the qbc technique for rapid diagnosis of vivax malaria wang xingzhen. Capital and test costs are high but, in busy haematology laboratories where large numbers of malaria requests are received daily, qbc screening may be a useful and. Wang, xingzhen, zhu, shenghua, liu, qing, hu, anqi, zan, zhongxue. What is the role of the quantitative buffy coat qbc. Sensitivities and specificities for the qbc and kawamotos acridine orange techniques com pared to giemsas stain for the diagnosis of malaria sensitivity % specificity % all samples qbc936 915 aoa 979 865 parasitaemia diagnosis system and by examination of thin blood smears. Field evaluation of the qbc technique for rapid diagnosis. Studies by means of immunofluorescence and blood smear by a.
As with trypanosomes, spirochetes concentrate in the qbc just above the. Sep 17, 2018 malaria in equatorial guinea remains a major public health problem. Wang x, zhu s, liu q, hu a, zan z, yu q, and yin q, 1996. Malaria diagnosis based on clinical signs and symptoms alone is not.
The quantitative buffy coat for the diagnosis of trypanosomes. Multiplex realtime pcr for diagnosing malaria in a non. These were i giemsastained thick blood films gtf, ii acridine orangestained thick aotf and thin aotnf blood films, iii the quantitative buffy coat technique qbc. The mainstay of malaria diagnosis has been the microscopic examination of blood, utilizing blood films. Capital and test costs are high but, in busy haematology laboratories where large numbers of malaria requests are received daily, qbc screening may be a useful and time. Comparison of quantitative buffy coat technique qbc with giemsastained thick film gtf for diagnosis of malaria. Both qbc and gtf techniques, however, recorded the same level of malaria in persons above 50 years of age. Several malaria diagnostic kits based on antigen detection of plasmodium falciparum have been developed, such as parasightf becton dickinson, cockeysville, md. Table of contents malaria vector classification of malaria signs and symptoms diagnosis malaria is a mosquitoborne infectious disease of human. Pdf a comparison of rapid diagnostic testing by plasmodium. The large number of deaths caused by malaria each year has increased interest in the development of effective malaria diagnoses. Field evaluation of the qbc technique for rapid diagnosis of vivax malaria. According to the qbc technique, the percentage positive for malaria in those examined increased steadily from age 0 to 39 years, and then decreased from 39 to 69 years, while the gtf technique revealed highest prevalence of malaria in age group 40 to 49 years.
This minimizes the risk of parasite resistance development, reduces drug wastage and unnecessary adverse. 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. Comparative evaluation of four techniques for the diagnosis. In severe cases it can cause yellow skin, seizures, coma, or death. Direct acridine orange fluorescence examination of blood.
The quantitative buffy coat qbc is a technique that is as sensitive as thick smears. Microscopy has been the gold standard for malaria diagnosis for decades. Although some methods lend themselves to automation eg. Tickborne relapsing fever imported from west africa. The qbc technique was designed to enhance microscopic detection of parasites and simplify malaria diagnosis. The world health organization recommends confirmatory testing using microscopybased techniques or rapid diagnostic tests rdt for all cases of suspected malaria.
Symptoms usually begin ten to fifteen days after being bitten by an infected mosquito. Malaria should be considered a potential medical emergency and should be treated accordingly. Qbc technique the qbc technique was designed to enhance microscopic detection of parasites and simplify malaria diagnosis 31. Drug resistance and genetic variation has altered many accepted morphological appearances of malaria species, and new technology has.
Results of qbc and rdt were compared with microscopy results for the diagnosis of malaria. Although blood is the sample most frequently used to make a diagnosis, both saliva and urine have been investigated as alternative, less invasive specimens. The quantitative buffy coat qbc technique is a commercially available test based on fluorescence microscopy wardlaw and levine, 1983. A successful malaria prevention and control program is dependent on availability of high quality laboratory diagnostic services. Various methods has been recommended by texts and literature. Prevention 1 table of contents malaria vector classification of malaria signs and symptoms 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. Malaria laboratory diagnosis external quality assessment. Several new methods of malaria diagnosis have recently been developed, but these all rely on clinical suspicion and, consequently, an explicit clinical request. Some laboratories use qbc as a screening test backed up by thickthin films on qbc. Towards ultrasensitive malaria diagnosis using surface. Because results cannot be used to speciate plasmodium, a thin smear must be examined.
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