Price, quality, and market dynamics of malaria rapid diagnostic tests: analysis of Global Fund 2009–2018 data

Background Rapid 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? Methods Data 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. Results Lower-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. Conclusions Advancements 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.

Modelling the epidemiology of malaria and spread of HRP2-negative Plasmodium falciparum following the replacement of HRP2-detecting rapid diagnostic tests

Malaria rapid diagnostic tests (RDTs) are dominated by products which use histidine-rich protein 2 (HRP2) to detect Plasmodium falciparum. The emergence of parasites lacking the pfhrp2 gene can lead to high rates of false-negative results amongst these RDTs. One solution to restore the ability to correctly diagnose falciparum malaria is to switch to an RDT which is not solely reliant on HRP2. This study used an agent-based stochastic simulation model to investigate the impact on prevalence and transmission caused by switching the type of RDT used once false-negative rates reached pre-defined thresholds within the treatment-seeking symptomatic population. The results show that low transmission settings were the first to reach the false-negative switch threshold, and that lower thresholds were typically associated with better long-term outcomes. Changing the diagnostic RDT away from a HRP2-only RDT is predicted to restore the ability to correctly diagnose symptomatic malaria infections, but often did not lead to the extinction of HRP2-negative parasites from the population which continued to circulate in low density infections, or return to the parasite prevalence and transmission levels seen prior to the introduction of the HRP2-negative parasite. In contrast, failure to move away from HRP2-only RDTs leads to near fixation of these parasites in the population, and the inability to correctly diagnose symptomatic cases. Overall, these results suggest pfhrp2-deleted parasites are likely to become a significant component of P. falciparum parasite populations, and that long-term strategies are needed for diagnosis and surveillance which do not rely solely on HRP2.

CRISPR-Cas System: A Promising Diagnostic Tool for Covid-19

More than a year has passed since the beginning of the 2019 novel coronavirus diseases (COVID-19) pandemic which has created massive problems globally affecting all aspects of people's life. Due to the emergence of new strains of the SARS-CoV-2, pandemic risk still remains, despite the start of vaccination. Therefore, rapid diagnostic tests are essential to control infection, improve clinical care and stop the spread of the disease. Recently CRISPR-based diagnostic tools have facilitated rapid diagnostic. Here, we review the diagnostic applications of CRISPR-Cas system in COVID-19.

Performance of the BinaxNOW COVID-19 Antigen Rapid Diagnostic Test for the Detection of SARS-CoV-2

Background: Diagnosis of COVID-19 disease primarily relies on nucleic acid amplification tests (NAAT) that amplify and detect viral RNA in specimens. These methods are expensive and time consuming. Antigen-based rapid diagnostic tests can substantially decrease turnaround time.Methods: We analyzed paired anterior nares swabs collected from symptomatic patients and asymptomatic healthcare workers being tested COVID-19. One swab was used for a direct RDT and the results were compared to NAAT.Results: 89 paired specimens were evaluated. The positive percent agreement (PPA) for the antigen RDT was 68.2%, and the negative percent agreement (NPA) was 98.5%. Despite a low PPA, the Κ statistic was 0.733 indicating substantial agreement with the NAAT result. The median cycle number in paired specimens with concordant results was significantly lower than in discordant specimens (21.3 versus 32.3; P=0.003).Conclusions: The RDT showed modest PPA and high NPA when compared to NAAT. The quick TAT and use of an inexpensive test more frequently could be useful in settings in which results from NAAT testing is delayed.

Comparing the Performance of HIV Rapid Diagnostic Tests Used in Zambia: a Systematic Review of Clinical Data.

Objective: To investigate the performance of the HIV RDTs used in Zambia. Method: 2,564 participants aged between 15 and 95 years from two sites in Lusaka province years were tested on OraQuick ADVANCE, Abbot Determine, and then confirmed on Uni-Gold Recombigen. The data from the participants were analyzed using SPSS version 25.0. Results: The 3 RDTs when compared to the 4th generation Abbot Architect results had the following results: OraQuick ADVANCE, Alere Determine and Uni-Gold Ultra, at 95% CI had Sensitivities of: 91.8%, 93.3% and 92.5% respectively. The specificities of OraQuick ADVANCE and Uni-Gold were the same (100.0%; 95% CI: 98.8 -100.0) but slightly different from Alere Determine (99.8%). Positive predictive values at 95% CI were 100% for OraQuick ADVANCE and Uni-Gold and 98.4% for Alere Determine. Negative predictive values (at 95% CIs) were 99.1, 99.2 and 99.1 for OraQuick ADVANCE, Alere Determine, and Uni-Gold Ultra respectively. The results showed that these RDTs could only detect 12 out of every 13 HIV positive results. Conclusion: Third generation RDTs are not effective in detecting acute positive cases. Fourth generation Rapid Tests are required to capture the positive cases being missed out.