Bedside diagnosis of imported malaria using the Binax Now malaria antigen detection test
Lothar WieseBrita BruunL. BækAlice Friis‐MøllerBente Gahrn‐HansenJoanna HansenOle HeltbergTove HøjbjergMaren Kathrine HornstrupBirgit KvinesdalGrethe GommeJørgen A. L. Kurtzhals
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Abstract:
Malaria may be misdiagnosed in non-endemic countries when the necessary experience for rapid expert microscopy is lacking. Rapid diagnostic tests may improve the diagnosis and may play a role as a bedside diagnostic tool. In a multicentre study we recruited patients suspected of malaria over a period of 14 months. The Binax Now Malaria rapid test was used at the bedside and in the clinical microbiology laboratory. The training of clinical staff was monitored and their experience with the use of the test was recorded. 542 patients were included, 80 of whom had malaria diagnosed by microscopy. The rapid test used at the bedside had a sensitivity of 88% for the detection of P. falciparum compared to 95% when the test was performed in the microbiology laboratory. The risk of technical problems and invalid tests was highest when the test was used at the bedside. The rapid diagnostic test may be useful for the diagnosis of P. falciparum malaria when used by routine laboratory staff, but could lead to misdiagnoses when used at the bedside. Microscopy is still essential in order to identify the few missed diagnoses, to determine the degree of parasitaemia, and to ensure species diagnosis, including mixed infections.Keywords:
Rapid diagnostic test
Diagnosis of malaria
Although microscopy is a standard diagnostic tool for malaria and the gold standard, it is infrequently used because of unavailability of laboratory facilities and the absence of skilled readers in poor resource settings. Malaria rapid diagnostic tests (RDT) are currently used instead of or as an adjunct to microscopy. However, at very low parasitaemia (usually < 100 asexual parasites/µl), the test line on malaria rapid diagnostic tests can be faint and consequently hard to visualize and this may potentially affect the interpretation of the test results. Fio Corporation (Canada), developed an automated RDT reader named Deki Reader™ for automatic analysis and interpretation of rapid diagnostic tests. This study aimed to compare visual assessment and automated Deki Reader evaluations to interpret malaria rapid diagnostic tests against microscopy. Unlike in the previous studies where expert laboratory technicians interpreted the test results visually and operated the device, in this study low cadre health care workers who have not attended any formal professional training in laboratory sciences were employed. Finger prick blood from 1293 outpatients with fever was tested for malaria using RDT and Giemsa-stained microscopy for thick and thin blood smears. Blood samples for RDTs were processed according to manufacturers' instructions automated in the Deki Reader. Results of malaria diagnoses were compared between visual and the automated devise reading of RDT and microscopy. The sensitivity of malaria rapid diagnostic test results interpreted by the Deki Reader was 94.1% and that of visual interpretation was 93.9%. The specificity of malaria rapid diagnostic test results was 71.8% and that of human interpretation was 72.0%. The positive predictive value of malaria RDT results by the Deki Reader and visual interpretation was 75.8 and 75.4%, respectively, while the negative predictive values were 92.8 and 92.4%, respectively. The accuracy of RDT as interpreted by DR and visually was 82.6 and 82.1%, respectively. There was no significant difference in performance of RDTs interpreted by either automated DR or visually by unskilled health workers. However, despite the similarities in performance parameters, the device has proven useful because it provides stepwise guidance on processing RDT, data transfer and reporting.
Tropical Medicine
Parasitology
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Prompt diagnosis of malaria cases with rapid diagnostic tests (RDTs) has been widely adopted as an effective malaria diagnostic tool in many malaria endemic countries, primarily due to their easy operation, fast result output, and straightforward interpretation. However, there has been controversy about the diagnostic accuracy of RDTs. This study was conducted to evaluate the diagnostic performances of the 2 commercially available malaria RDT kits, RapiGEN Malaria Ag Pf/Pv (pLDH/pLDH) and Asan EasyTestTM Malaria Ag Pf/Pv (HRP-2/pLDH) for their abilities to detect Plasmodium species in blood samples collected from Ugandan patients with malaria. To evaluate the diagnostic performances of these 2 RDT kits, 229 blood samples were tested for malaria infection by microscopic examination and a species-specific nested polymerase chain reaction. The detection sensitivities for P. falciparum of Malaria Ag Pf/Pv (pLDH/pLDH) and Asan EasyTestTM Malaria Ag Pf/Pv (HRP-2/pLDH) were 87.83% and 89.57%, respectively. The specificities of the 2 RDTs were 100% for P. falciparum and mixed P. falciparum/P. vivax infections. These results suggest that the 2 RDT kits showed reasonable levels of diagnostic performances for detection of the malaria parasites from Ugandan patients. However, neither kit could effectively detect P. falciparum infections with low parasitaemia (<500 parasites/μl).
Plasmodium (life cycle)
Rapid diagnostic test
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Accurate diagnosis of malaria is vital for the effectiveness of parasite clearance interventions in elimination settings. Thus, evaluating the diagnostic performance of rapid diagnostic tests (RDTs) used in malaria parasite clearance interventions in elimination settings is essential. Therefore, this study aimed to evaluate the diagnostic performance of rapid diagnostic tests recently used in detecting malaria parasites in northwest Ethiopia. A facility-based cross-sectional study was conducted from November 2020 to February 2021 comparing PfHRP2/pLDH CareStart malaria RDTs with light microscopy and polymerase chain reaction (PCR). Blood samples were collected from 310 febrile patients who attended the outpatient department and examined using CareStart RDTs, light microscopy, and PCR. Statistical analyses were performed using STATA/SE version 17.0. The sensitivity of PfHRP2/pLDH CareStart malaria RDTs, regardless of species, was 81.0% [95% CI, 75.3, 86.7] and 75.8% [95% CI, 69.6, 82.0] compared to light microscopy and PCR, while the specificity was 96.8% [95% CI, 93.7, 99.9] and 93.2% [95% CI, 88.6, 97.8], respectively. The false-negative rate of CareStart malaria RDTs in comparison with light microscopy and PCR was 19.0% and 24.2%, respectively. The level of agreement beyond chance between tests was substantial, RDT versus microscopy was 75.0% and RDT versus PCR was 65.1%. The diagnostic performance of PfHRP2/pLDH CareStart RDTs in detecting malaria parasites among febrile patients in the study area was below the recommended WHO standard. The limited diagnostic performance of RDTs in the malaria elimination area undoubtedly affects the impact of malaria parasite clearance interventions. Therefore, parasite clearance intervention like targeted mass drug administration with antimalarial drugs is recommended to back up the limited diagnostic performance of the RDT or replace the existing malaria RDTs with more sensitive, field-deployable, and affordable diagnostic tests.
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In the prevention and control of malaria, Prompt and accurate diagnosis is the key to effective disease management. Giemsa microscopy and rapid diagnostic tests (RDTs) are the diagnostic tests each with characteristic strengths and limitations is the best way for accurate diagnosis has a key role for malaria control successfully. Reduction in morbidity and drug resistance intensity of malaria require a parasite based diagnostic methods. A parallel commitment is needed in production of antimalarial drug or malaria vaccine along with improvement in diagnostic tests and their availability to people in endemic areas.endemic areas. [Jain S NJIRM 2014; 5(4) :82-87]
Key Words: Microscopy, Malaria, Rapiddiagnostic test, Malaria diagnosis, Parasetaemia, Plasmodium, Antimalarial drug.
Rapid diagnostic test
Diagnosis of malaria
Giemsa stain
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Malaria continues to be a major burden in the endemic regions of Kenya. Health outcomes associated with case management are dependent on the use of appropriate diagnostic methods. Rapid diagnostic tests (RDTs) have provided an important tool to help implement the WHO recommended parasite-based diagnosis in regions where expert microscopy is not available. One of the questions that must be answered when implementing RDTs is whether these tests are useful in a specific endemic region, as well as the most appropriate RDT to use. Data on the sensitivity and specificity of RDT test kits is important information to help guide test selection by national malaria control programmes. This study evaluated the diagnostic performance of RDTs including First Response (FR), CareStart (CS), SD Bioline (SD), and Binax Now (BN). The performance of these malaria kits was compared to microscopy, the gold standard, for the detection of malaria parasites. The malaria RDTs were also compared to PCR which is a more sensitive reference test. Five-hundred participants were included in the study through community screening (50 %) and testing suspected malaria cases referred from health facilities. Of the 500 participants recruited, 33 % were malaria positive by microscopy while 51.2 % were positive by PCR. Compared to microscopy, the sensitivity of eight RDTs to detect malaria parasites was 90.3–94.8 %, the specificity was 73.3–79.3 %, the positive predictive value was 62.2–68.8 %, and the negative predictive value was 94.3–96.8 %. Compared to PCR, the sensitivity of the RDTs to detect malaria parasites was 71.1–75.4 %, the specificity was 80.3–84.4 %, the positive predictive value was 80.3–83.3 %, and the negative predictive value was 73.7–76.1 %. The RDTs had a moderate measure of agreement with both microscopy (>80.1 %) and PCR (>77.6 %) with a κ > 0.6. The performance of the evaluated RDTs using field samples was moderate; hence they can significantly improve the quality of malaria case management in endemic regions in Kenya by ensuring appropriate treatment of malaria positive individuals and avoiding indiscriminate use of anti-malarial drugs for parasite negative patients.
Rapid diagnostic test
Gold standard (test)
Diagnosis of malaria
Tropical Medicine
Parasitology
Positive predicative value
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In recent years, rapid diagnostic tests (RDTs) have been widely used for malaria detection, primarily because of their simple operation, fast results, and straightforward interpretation. The Asan EasyTest™ Malaria Pf/Pan Ag is one of the most commonly used malaria RDTs in several countries, including Korea and India. In this study, we tested the diagnostic performance of this RDT in Uganda to evaluate its usefulness for field diagnosis of malaria in this country. Microscopic and PCR analyses, and the Asan EasyTest™ Malaria Pf/Pan Ag rapid diagnostic test, were performed on blood samples from 185 individuals with suspected malaria in several villages in Uganda. Compared to the microscopic analysis, the sensitivity of the RDT to detect malaria infection was 95.8% and 83.3% for Plasmodium falciparum and non-P. falciparum, respectively. Although the diagnostic sensitivity of the RDT decreased when parasitemia was ≤500 parasites/µl, it showed 96.8% sensitivity (98.4% for P. falciparum and 93.8% for non-P. falciparum) in blood samples with parasitemia ≥100 parasites/µl. The specificity of the RDT was 97.3% for P. falciparum and 97.3% for non-P. falciparum. These results collectively suggest that the accuracy of the Asan EasyTest™ Malaria Pf/Pan Ag makes it an effective point-of-care diagnostic tool for malaria in Uganda. Key words: Plasmodium falciparum, rapid diagnostic test, malaria, point-of-care testing, field test, Uganda
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Diagnosis of malaria
Point-of-Care Testing
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Treatment of malaria, with the appropriate diagnostic tool, helps to reduce morbidity and mortality in children. The absence of resources and inadequate labor in emerging countries like Ghana make malaria microscopy difficult. The Rapid Diagnostic Test kit (RDT) remains unpopular despite its availability and ease of use because of limited research on its effectiveness leading to over prescription of antimalarial drugs. This study shows how reliable the malaria diagnostic test is. Out of 132 children were recruited in all into the study with more females (59.1%) than males (40.9%). 35 (26.5%) of children who were recruited tested positive for Plasmodium falciparum with the Malaria rapid diagnostic test cassette while 97 (73.5%) children tested negative for Plasmodium falciparum with the malaria diagnostic test cassette. In Malaria Microscopy, 35 (26.5%) children tested positive while 97 (73.5%) tested negative for malaria parasites. Out of the 35 children who tested positive, RDT picked 33 as positive and 2 as negative (sensitivity = 94.3%). While out of the 97 that tested negative for microscopy, RDT picked 94 as negative and 3 as positive (specificity= 96.9%). The positive predictive value and negative predictive values are 91.7% and 97.9%, respectively.This clearly shows the Rapid Diagnostic Test (RDT) is an effective diagnostic tool for the testing of malaria in children in the Akuapem North District in the Eastern Region of Ghana.
Rapid diagnostic test
Diagnosis of malaria
Positive predicative value
Outpatient clinic
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Introduction: Malaria is a life-threatening disease caused by infection with Plasmodium parasites. Rapid diagnostic tests (RDTs) have been used for the diagnosis of malaria without special equipment by unskilled personnel over the last 15 years. The treatment should only be given after the clinical diagnosis confirmed by RDT or microscopy. RDTs' specificity and sensitivity have been reported as >95% by the World Health Organization - Foundation for Initiative New Diagnostics (WHO-FIND).
Case Report: A 30-years-old male and a 23-years-old female presented to our emergency department with fever and history of a visit to a malaria-endemic country. Plasmodium trophozoites were seen in the blood smear samples via light microscopy. However, RDTs were negative. The patients were treated according to their pathogens.
Conclusion: Rarely, RDT might result in a false negative in the diagnosis of malaria. People travelling to endemic areas should be closely monitored. Emergency department physicians should not neglect microscopy which is the gold standard for diagnosis of malaria.
Rapid diagnostic test
Gold standard (test)
Diagnosis of malaria
Negativity effect
Blood smear
Clinical Diagnosis
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Diagnosis of malaria cases depends on parasitological examination. Since 2006, the Department of Infectious Diseases at the Joseph Raseta Befelatanana University Hospital in Madagascar has been using the malaria rapid diagnostic test. The percentage of malaria cases (presumed or confirmed) in relation to the number of hospitalized patients has decreased. It was 23.4% in 2003, 10.3% in 2006 and 4.3% in 2008 (p<0.01532). To improve management of malaria cases and rationalize use of antimalarial agents, diagnosis should be confirmed by rapid diagnostic tests.
Diagnosis of malaria
Rapid diagnostic test
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