Dataset Information

Photo-based External Quality Assessment of Malaria rapid diagnostic tests in a non-endemic setting.

ABSTRACT:

Introduction

In non-endemic settings, expertise in malaria microscopy is limited and rapid diagnostic tests (RDTs) are an adjunct to malaria diagnosis.

Aim

We performed an External Quality Assessment (EQA) on reading and interpretation of malaria RDTs in a non-endemic setting.

Methods

Participants were medical laboratories in Belgium and the Grand Duchy of Luxembourg using malaria RDTs; they received (i) 10 high-resolution photographs presenting test line combinations of RDTs with interpretations listed in a multiple choice format and (ii) a questionnaire about their practices of malaria diagnosis.

Results

Among 135 subscribing laboratories, 134 (99.3%) used 139 RDT products (11 different products from 8 brands). After exclusion of the results of one laboratory, analysis was done for 133 laboratories using 137 RDT products. Scores of 10/10, 9/10 and 8/10 were achieved for 58.4%, 13.1% and 8.0% of 137 RDT products respectively. For three-band P. falciparum-pan-Plasmodium RDTs (113 (82.5%) products, 6 brands), most frequent errors were (1) disregarding faint test lines (18.6%), (2) reporting invalid instead of P. falciparum (16.8%) and (3) reporting "Plasmodium spp., no further differentiation possible" without mentioning the presence or absence of P. falciparum (11.5%). For four-band RDTs (21 (15.3%) products, 1 brand), errors were (4) disregarding faint P. vivax test lines (47.6%) and (5) reporting "Plasmodium spp., no further differentiation possible" without mentioning the presence of P. falciparum and P. vivax (28.6%). Instructions for use (IFU) of only 4 out of 10 RDT products mentioned to interpret faint-intensity test lines as positive (conducive to errors 1 and 4) and IFU of 2 products displayed incorrect information (conducive to errors 2 and 5). Outside of office hours, 36.1% of participants relied on RDTs as the initial diagnostic test; 13.9% did not perform microscopic confirmation.

Conclusion

Reading and interpretation of malaria RDTs was satisfactory, but errors were embedded in the instructions for use of the products. Relying on RDTs alone for malaria diagnosis (about one third of participants) is not a recommended practice.

SUBMITTER: Vernelen K

PROVIDER: S-EPMC6118386 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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Publications

Photo-based External Quality Assessment of Malaria rapid diagnostic tests in a non-endemic setting.

Vernelen Kris K Barbé Barbara B Gillet Philippe P Van Esbroeck Marjan M China Bernard B Jacobs Jan J

PloS one 20180831 8

<h4>Introduction</h4>In non-endemic settings, expertise in malaria microscopy is limited and rapid diagnostic tests (RDTs) are an adjunct to malaria diagnosis.<h4>Aim</h4>We performed an External Quality Assessment (EQA) on reading and interpretation of malaria RDTs in a non-endemic setting.<h4>Methods</h4>Participants were medical laboratories in Belgium and the Grand Duchy of Luxembourg using malaria RDTs; they received (i) 10 high-resolution photographs presenting test line combinations of RD ...[more]

PMID: 30169508

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Project description:BackgroundMalaria has a negative effect on the outcome of pregnancy. Pregnant women are at high risk of severe malaria and severe haemolytic anaemia, which contribute 60-70% of foetal and perinatal losses. Peripheral blood smear microscopy under-estimates sequestered placental infections, therefore malaria rapid diagnostic tests (RDTs) detecting histidine rich protein-2 antigen (HRP-2) in peripheral blood are a potential alternative.MethodsHRP-2 RDTs accuracy in detecting malaria in pregnancy (MIP >28 weeks gestation) and placental Plasmodium falciparum malaria (after childbirth) were conducted using Giemsa microscopy and placental histopathology respectively as the reference standard. The study was conducted in Mbale Hospital, using the midwives to perform and interpret the RDT results. Discordant results samples were spot checked using PCR techniques.ResultsAmong 433 febrile women tested, RDTs had a sensitivity of 96.8% (95% CI 92-98.8), specificity of 73.5% (95% CI 67.8-78.6), a positive predictive value (PPV) of 68.0% (95% CI 61.4-73.9), and negative predictive value (NPV) of 97.5% (95% CI 94.0-99.0) in detecting peripheral P. falciparum malaria during pregnancy. At delivery, in non-symptomatic women, RDTs had a 80.9% sensitivity (95% CI 57.4-93.7) and a 87.5% specificity (95%CI 80.9-92.1), PPV of 47.2% (95% CI 30.7-64.2) and NPV of 97.1% (95% CI 92.2-99.1) in detecting placental P. falciparum infections among 173 samples. At delivery, 41% of peripheral infections were detected by microscopy without concurrent placental infection. The combination of RDTs and microscopy improved the sensitivity to 90.5% and the specificity to 98.4% for detecting placental malaria infection (McNemar's X(2)> 3.84). RDTs were not superior to microscopy in detecting placental infection (McNemar's X(2)< 3.84). Presence of malaria in pregnancy and active placental malaria infection were 38% and 12% respectively. Placental infections were associated with poor pregnancy outcome [pre-term, still birth and low birth weight] (aOR = 37.9) and late pregnancy malaria infection (aOR = 20.9). Mosquito net use (aOR 2.1) and increasing parity (aOR 2.7) were associated with lower risk for malaria in pregnancy.ConclusionUse of HRP-2 RDTs to detect malaria in pregnancy in symptomatic women was accurate when performed by midwives. A combination of RDTs and microscopy provided the best means of detecting placental malaria. RDTs were not superior to microscopy in detecting placental infection. With a high sensitivity and specificity, RDTs could be a useful tool for assessing malaria in pregnancy, with further (cost-) effectiveness studies.

Project description: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.

Project description:BackgroundThe diagnosis of malaria, using microscopy or rapid diagnostic tests (RDTs), requires the collection of capillary blood. This procedure is relatively simple to perform but invasive and poses potential risks to patients and health workers, arising from the manipulation of potentially infectious bodily fluids. Less or non-invasive diagnostic tests, based on urine, saliva or requiring no sampling, have the potential to generate less discomfort for the patient and to offer simpler and less risky testing procedures that could be safely performed by untrained staff or even self-performed. To explore the potential acceptance and perceived value of such non-invasive tests, an online, international survey was conducted to gather feedback from National Malaria Control Programme (NMCP) representatives.MethodsAn online survey comprising nineteen questions, available in English, French or Spanish, was emailed to 300 individuals who work with NMCPs in malaria-endemic countries. Answers were collected between November and December 2017; responses were qualitatively analysed to identify key themes and trends and quantitatively analysed to determine average values stratified by region.ResultsResponses were received from 70 individuals, from 33 countries. Approximately half of the respondents (52 %) considered current blood-based tests for malaria to be minimally invasive and non-problematic in their setting. For these participants, non-invasive tests would only be of interest if they brought additional performance improvements, as compared with the performance of microscopy and RDTs. Most respondents were of the view that saliva-based (80 %) and urine-based (66 %) tests would be more readily acceptable among children than blood-based tests. Potential use-case scenarios of interest for both saliva- and urine-based tests were ease-of-testing by community health workers, additional surveillance, self-testing, and outbreak investigation. Many respondents (41 %) thought that if saliva-based tests retailed at <$0.50 per unit they could largely replace conventional RDTs, whereas only 25 % of respondents thought a similarly priced urine-based test would do so.ConclusionsAlthough limited to NMCP stakeholders, this survey indicated that current tests for malaria, based on capillary blood, are generally perceived to be minimally invasive and non-problematic. Non-invasive tests, especially if saliva-based, would be welcome if they could match or out-perform the price and performance of current blood-based tests.

Project description:IntroductionInternal and external quality control (QC) of rapid diagnostic tests (RDTs) is important to increase reliability of RDTs currently used to diagnose malaria. However, cross-checking of used RDTs as part of quality assurance can rarely be done by off-site personnel because there is no guarantee of retaining visible test lines after manufacturers' recommended reading time. Therefore, this study examined the potential of using Fionet™ technology for remote RDT quality monitoring at seven clinics, identifying reasons for making RDT processing and interpretation errors, and taking corrective actions for improvement of diagnosis and consequently improved management of febrile patients.MethodsThe study was conducted at seven military health facilities in Mainland Tanzania and utilized RDTs capable of detecting Plasmodium falciparum specific Histidine-rich protein 2 (Pf-HRP2) and the genus specific Plasmodium lactate dehydrogenase (pLDH) for other species of plasmodium (P. vivax, P. malariae or P. ovale; pan-pLDH). Patients' data and images of processed RDTs from seven clinics were uploaded on a Fionet web portal and reviewed regularly to monitor preparation procedures and visual interpretation of test results compared to automated analysis using the Deki reader of RDT. Problems detected were rapidly communicated to remote laboratory personnel at the clinic for corrective action and follow-up of patients who were falsely diagnosed as negative and missed treatment. Factors contributing to making errors in visual interpretation of RDT results were analyzed during visits to the health facilities.ResultsA total of 1,367 (1.6%) out of 83,294 RDT test images uploaded to the Fionet portal had discordant test results of which 822 (60.1%) and 545 (39.9%) were falsely reported as negative and positive, respectively. False negative and false positive test results were common for a single test line in 515 (62.7%) and 741 (54.2%) tests, respectively. Out of 1,367 RDT images assessed, 98 (7.2%) had quality problems related to preparation procedures of which 95(96.9%) errors were due to putting too much blood on the sample well or insufficient buffer in the respective wells. The reasons for discrepant results included, false reporting of none existent lines in 526 (38.5%) tests, missing a faint positive line in 493 (36.1%), missing a strong positive line in 248(18.1%) and errors caused by poorly processed RDTs in 96 (7.2%) tests. Among the false negative tests (n = 822), 669 (48.9%) patients were eligible for follow-up and only 339 (48.5%) were reached and 291 (85.8%) received appropriate anti-malaria therapy.ConclusionFionet technology enabled remote monitoring of RDT quality issues, identifying reasons contributing to laboratory personnel making errors and provided a rapid method to implement corrective actions at remote sites to improve malaria diagnosis and consequently improved health care management of febrile patients infected with malaria.

Project description:BACKGROUND: The World Health Organization recommends parasitological confirmation of all malaria cases. Tanzania is implementing a phased rollout of malaria rapid diagnostic tests (RDTs) for routine use in all levels of care as one strategy to increase parasitological confirmation of malaria diagnosis. This study was carried out to evaluated artemisinin combination therapy (ACT) prescribing patterns in febrile patients with and without uncomplicated malaria in one pre-RDT implementation and one post-RDT implementation area. METHODS: A cross-sectional health facility surveys was conducted during high and low malaria transmission seasons in 2010 in both areas. Clinical information and a reference blood film on all patients presenting for an initial illness consultation were collected. Malaria was defined as a history of fever in the past 48 h and microscopically confirmed parasitaemia. Routine diagnostic testing was defined as RDT or microscopy ordered by the health worker and performed at the health facility as part of the health worker-patient consultation. Correct diagnostic testing was defined as febrile patient tested with RDT or microscopy. Over-testing was defined as a non-febrile patient tested with RDT or microscopy. Correct treatment was defined as patient with malaria prescribed ACT. Over-treatment was defined as patient without malaria prescribed ACT. RESULTS: A total of 1,247 febrile patients (627 from pre-implementation area and 620 from post-implementation area) were included in the analysis. In the post-RDT implementation area, 80.9% (95% CI, 68.2-89.3) of patients with malaria received recommended treatment with ACT compared to 70.3% (95% CI, 54.7-82.2) of patients in the pre-RDT implementation area. Correct treatment was significantly higher in the post-implementation area during high transmission season (85.9% (95% CI, 72.0-93.6) compared to 58.3% (95% CI, 39.4-75.1) in pre-implementation area (p?=?0.01). Over-treatment with ACT of patients without malaria was less common in the post-RDT implementation area (20.9%; 95% CI, 14.7-28.8) compared to the pre-RDT implementation area (45.8%; 95% CI, 37.2-54.6) (p?<?0.01) in high transmission. The odds of overtreatment was significantly lower in post- RDT area (adjusted Odds Ratio (OR: 95% CI) 0.57(0.36-0.89); and much higher with clinical diagnosis adjusted OR (95% CI) 2.24(1.37-3.67) CONCLUSION: Implementation of RDTs increased use of RDTs for parasitological confirmation and reduced over-treatment with ACT during high malaria transmission season in one area in Tanzania. Continued monitoring of the national RDT rollout will be needed to assess whether these changes in case management practices will be replicated in other areas and sustained over time. Additional measures (such as refresher trainings, closer supervisions, etc.) may be needed to improve ACT targeting during low transmission seasons.

Project description:BackgroundRapid diagnostic tests (RDTs) for malaria are a vital part of global malaria control. Over the past decade, RDT prices have declined, and quality has improved. However, the relationship between price and product quality and their larger implications on the market have yet to be characterized. This analysis used purchase data from the Global Fund together with product quality data from the World Health Organization (WHO) and Foundation for Innovative New Diagnostics (FIND) Malaria RDT Product Testing Programme to understand three unanswered questions: (1) Has the market share by quality of RDTs in the Global Fund's procurement orders changed over time? (2) What is the relationship between unit price and RDT quality? (3) Has the market for RDTs financed by the Global Fund become more concentrated over time?MethodsData from 10,075 procurement transactions in the Global Fund's database, which includes year, product, volume, and price, was merged with product quality data from all eight rounds of the WHO-FIND programme, which evaluated 227 unique RDT products. To describe trends in market share by quality level of RDT, descriptive statistics were used to analyse trends in market share from 2009 to 2018. A generalized linear regression model was then applied to characterize the relationship between price and panel detection score (PDS), adjusting for order volume, year purchased, product type, and manufacturer. Third, a Herfindahl-Hirschman Index (HHI) score was calculated to characterize the degree of market concentration.ResultsLower-quality RDTs have lost market share between 2009 and 2018, as have the highest-quality RDTs. No statistically significant relationship between price per test and PDS was found when adjusting for order volume, product type, and year of purchase. The HHI was 3,570, indicating a highly concentrated market.ConclusionsAdvancements in RDT affordability, quality, and access over the past decade risk stagnation if health of the RDT market as a whole is neglected. These results suggest that from 2009 to 2018, this market was highly concentrated and that quality was not a distinguishing feature between RDTs. This information adds to previous reports noting concerns about the long-term sustainability of this market. Further research is needed to understand the causes and implications of these trends.

Dataset Information

Photo-based External Quality Assessment of Malaria rapid diagnostic tests in a non-endemic setting.

Introduction

Aim

Methods

Results

Conclusion

Publications

Photo-based External Quality Assessment of Malaria rapid diagnostic tests in a non-endemic setting.

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