A novel collection cup for tuberculosis sputum in South Africa: engineering design and user testing considerations

Low-cost, targeted engineering interventions can revolutionize health care, particularly in low-income environments. We outline a process for user testing of novel sputum collection cup models for PCR-based based tuberculosis assays in Cape Town, South Africa. Providing a sputum sample is difficult for many patients, and the quality of the sample affects downstream test performance. Observational data was collected from six representative sites including outpatient clinics, hospitals, and processing laboratories, and interviews were performed with individuals involved with sputum collection (n=10), processing (n=10), and transportation (n=3). Participants compared “rocket” and “squeeze” prototypes to the current cup by answering standardized questions and ranking the usability and perceived safety of the models. Sputum collectors found the current model significantly easier to use (p-value: 0.0091) and safer (p-value: 0.0044) than the “squeeze” model. Sputum processors found the “squeeze” model more difficult to use than both the current jar (p-value: 0.0091) and the “rocket” model (p-value: 0.0012). They additionally perceived the “squeeze” model to be less safe than the “rocket” prototype (p-value: 0.0007). These results were incorporated into a remodelled sputum collection cup that contains a stable, upright base, maximum and minimum markers, and a tight seal to meet the needs of primary users.