Usability of a point-of-care diagnostic to identify glucose-6-phosphate dehydrogenase deficiency: a multi-country assessment of test label comprehension and results interpretation.

BACKGROUND: Point-of-care glucose-6-phosphate dehydrogenase (G6PD) testing has the potential to make the use of radical treatment for vivax malaria safer and more effective. Widespread use of G6PD tests as part of malaria case management has been limited, in part due to due concerns regarding product usability, user training, and supervision. This study seeks to assess how well end users can understand the Standard™ G6PD Test (SD Biosensor, Suwon, South Korea) workflow, result output, and label after training. This will ultimately help inform test registration and introduction. METHODS: Potential G6PD test users who provide malaria case management at three sites in Brazil, Ethiopia, and India were trained on the use of the SD Biosensor Standard G6PD Test and assessed based on their ability to understand the test workflow and interpret results. The assessment was done through a questionnaire, designed to assess product usability against key technical product specifications and fulfill regulatory evidence requirements. Any participant who obtained 85% or above correct responses to the questionnaire was considered to adequately comprehend how to use and interpret the test. RESULTS: Forty-five participants, including malaria microscopists, laboratory staff, nurses, and community health workers took part in the study. Seventy-eight percent of all participants in the study (35/45) obtained passing scores on the assessment with minimal training. Responses to the multiple-choice questions indicate that most participants understood well the test intended use, safety claims, and warnings. The greatest source of error regarding the test was around the correct operating temperature. Most test results were also read and interpreted correctly, with the haemoglobin measurement being a more problematic output to interpret than the G6PD measurement. CONCLUSIONS: These data results show how a standardized tool can be used to assess a user's ability to run a point-of-care diagnostic and interpret results. When applied to the SD Biosensor Standard G6PD Test, this tool demonstrates that a range of users across multiple contexts can use the test and suggests improvements to the test instructions and training that can improve product usability, increase user comprehension, and ultimately contribute to more widespread effective use of point-of-care G6PD tests. TRIAL REGISTRATION: NCT04033640.

Global economic costs due to vivax malaria and the potential impact of its radical cure: A modelling study.

BACKGROUND: In 2017, an estimated 14 million cases of Plasmodium vivax malaria were reported from Asia, Central and South America, and the Horn of Africa. The clinical burden of vivax malaria is largely driven by its ability to form dormant liver stages (hypnozoites) that can reactivate to cause recurrent episodes of malaria. Elimination of both the blood and liver stages of the parasites ("radical cure") is required to achieve a sustained clinical response and prevent ongoing transmission of the parasite. Novel treatment options and point-of-care diagnostics are now available to ensure that radical cure can be administered safely and effectively. We quantified the global economic cost of vivax malaria and estimated the potential cost benefit of a policy of radical cure after testing patients for glucose-6-phosphate dehydrogenase (G6PD) deficiency. METHODS AND FINDINGS: Estimates of the healthcare provider and household costs due to vivax malaria were collated and combined with national case estimates for 44 endemic countries in 2017. These provider and household costs were compared with those that would be incurred under 2 scenarios for radical cure following G6PD screening: (1) complete adherence following daily supervised primaquine therapy and (2) unsupervised treatment with an assumed 40% effectiveness. A probabilistic sensitivity analysis generated credible intervals (CrIs) for the estimates. Globally, the annual cost of vivax malaria was US$359 million (95% CrI: US$222 to 563 million), attributable to 14.2 million cases of vivax malaria in 2017. From a societal perspective, adopting a policy of G6PD deficiency screening and supervision of primaquine to all eligible patients would prevent 6.1 million cases and reduce the global cost of vivax malaria to US$266 million (95% CrI: US$161 to 415 million), although healthcare provider costs would increase by US$39 million. If perfect adherence could be achieved with a single visit, then the global cost would fall further to US$225 million, equivalent to $135 million in cost savings from the baseline global costs. A policy of unsupervised primaquine reduced the cost to US$342 million (95% CrI: US$209 to 532 million) while preventing 2.1 million cases. Limitations of the study include partial availability of country-level cost data and parameter uncertainty for the proportion of patients prescribed primaquine, patient adherence to a full course of primaquine, and effectiveness of primaquine when unsupervised. CONCLUSIONS: Our modelling study highlights a substantial global economic burden of vivax malaria that could be reduced through investment in safe and effective radical cure achieved by routine screening for G6PD deficiency and supervision of treatment. Novel, low-cost interventions for improving adherence to primaquine to ensure effective radical cure and widespread access to screening for G6PD deficiency will be critical to achieving the timely global elimination of P. vivax.

Assessment of serum aflatoxin B1 levels in neonatal jaundice with glucose-6-phosphate dehydrogenase deficiency: a preliminary study.

Aflatoxin (AF) contamination of food products is still a major health issue globally. Prior studies suggest that exposure to AFs during pregnancy has harmful fetal outcomes. This preliminary study was designed to assess serum AFB1 levels in neonatal jaundice (NNJ) secondary to glucose-6-phosphate dehydrogenase (G6PD) deficiency. Twenty-four full-term neonates with hemolytic jaundice secondary to G6PD deficiency were enrolled in the study. Erythrocyte G6PD status was assessed colorimetrically, and serum aflatoxin B1 (AFB1) concentrations were measured by high-performance liquid chromatography. The results revealed that AFB1 was detected in 58% (14/24) of the studied newborns while detected in 75% (18/24) of their mothers. AFB1 positive cases had a highly significantly lower birthweight and G6PD activity (P = 0.001, each). Birthweight (r = - 0.574, P = 0.032) and G6PD activity (r = - 0.585, P = 0.028) negatively correlated with serum AFB1 levels while serum alanine aminotransferase activity positively correlated with serum AFB1 levels (r = 0.536, P = 0.048). Maternal AFB1 exposure is associated with adverse birth outcomes as verified by the low birthweight and the evident decline in the activity of G6PD enzyme with the resultant hemolytic NNJ.

Humanized mouse model of glucose 6-phosphate dehydrogenase deficiency for in vivo assessment of hemolytic toxicity.

Individuals with glucose 6-phosphate dehydrogenase (G6PD) deficiency are at risk for the development of hemolytic anemia when given 8-aminoquinolines (8-AQs), an important class of antimalarial/antiinfective therapeutics. However, there is no suitable animal model that can predict the clinical hemolytic potential of drugs. We developed and validated a human (hu)RBC-SCID mouse model by giving nonobese diabetic/SCID mice daily transfusions of huRBCs from G6PD-deficient donors. Treatment of SCID mice engrafted with G6PD-deficient huRBCs with primaquine, an 8-AQ, resulted in a dose-dependent selective loss of huRBCs. To validate the specificity of this model, we tested known nonhemolytic antimalarial drugs: mefloquine, chloroquine, doxycycline, and pyrimethamine. No significant loss of G6PD-deficient huRBCs was observed. Treatment with drugs known to cause hemolytic toxicity (pamaquine, sitamaquine, tafenoquine, and dapsone) resulted in loss of G6PD-deficient huRBCs comparable to primaquine. This mouse model provides an important tool to test drugs for their potential to cause hemolytic toxicity in G6PD-deficient populations.

Drug-induced glucose-6-phosphate dehydrogenase deficiency-related hemolysis risk assessment.

Glucose-6-phosphate dehydrogenase (G6PD) is an essential enzyme that protects human red blood cells from premature destruction caused by oxidative damage. People suffering from G6PD deficiency would be vulnerable to various oxidative substances, such as fava beans and oxidant drugs. Until now, many institutes, organizations or domain experts have compiled low-risk or high-risk drugs collection for patients with G6PD deficiency, mainly from the case report or clinical trails. Recently, we have explored a classification system to predict drug-induced hemolytic potential. In this paper, we screen the normally used over-the-counter (OTC) drugs for "high-risk" and "low-risk" ones to G6PD deficient patients by this system.

Low-grade haemolysis and assessment of iron status during the steady state in G6PD-deficient subjects.

We evaluated the iron status of 50 Sicilian patients with G6PD deficiency under steady-state conditions and compared our results with those for 50 control patients. We studied haemolysis and iron indices to evaluate the iron balance. These patients could be considered to be at risk of iron overload as a result of increased bone marrow activity. Reticulocytosis and macrocytosis with reduced levels of haptoglobin were found in the G6PD-deficient subjects, both of which are evidence of a moderate haemolysis. Iron status within the normal range, without iron overload or iron deficiency, was found.