A user-friendly point-of-care device for G6PDH determination

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Abstract Malaria caused by Plasmodium vivax threatens over 2 billion people globally and sickens tens of millions annually. Radical cure for P. vivax malaria includes therapy aimed both at the acute attack (blood schizontocidal) and against future attacks (hypnozoitocidal). The only hypnozoitocides available are 8-aminoquinolines such as primaquine or tafenoquine. However, clinicians often do not prescribe 8-aminoquinolines due to the high prevalence (8%) of individuals with various levels of inherited Glucose-6-phosphate dehydrogenase (G6PD) deficiencies and 8-aminoquinolines can cause life-threatening acute hemolytic anemia in patients with moderate to severe G6PD deficiencies. There are no commercially available point-of-care (POC) tests that can quantify both Hgb and G6PD from a finger-stick sample. In Phase I, we successfully met the performance as outlined by the World Health Organization and the Program for Appropriate Technology in Health (PATH). Results of whole blood and plasma testing revealed excellent concordance between our PreQuine System and current reference methods. In Phase II, we propose to manufacture a simple-to-use inexpensive device, the PreQuine System, that can be used in the field or clinical setting, which will have a number of valuable features. First, the PreQuine System will be comprised of test strips and a hand-held meter with an on-board temperature correction algorithm. Second, the PreQuine System will be rugged, low cost, and minimally invasive for broad use in clinical settings, public health labs and targeted outreach programs. To complete development of the PreQuine System, we will: (1) Finalize Assay Development by Assessing Bioactive Components. Three commercially available diaphorases will be tested to ensure (1) a high degree of activity at the optimal pH (2) long-term stability; and (3) no inhibition in the presence of maleimide; (2) Transition from Hand Assembly to Semi-Automated Assembly of Test Strips. This will be achieved by optimizing process capabilities of coating, slitting and laminating the strips into 5-up card stock.; (3) Incorporate a Temperature Correction Factor (TFC). The PreQuine system must be enable function in a working temperature of 18°C to 40°C. The TFC will be incorporated into the software and correct for temperature differences. Finally, (4) Validation of the PreQuine System. Validation for G6PD and Hgb levels will demonstrate concordance between the manufactured test strips and reference methods. Once validated and commercialized, the PreQuine System will provide point of care diagnostic tool to identify G6PD deficient individuals who can or cannot tolerate 8-aminoquinoline treatment, which will transform malaria treatment strategies and aid in the eradication of P.vivax and P. ovale malaria.