Methods
Summary
Objectives
To determine the effectiveness of Foldscope microscopy for Schistosoma haematobium detection, as measured by sensitivity, specificity, PPV, NPV, and accuracy of this diagnostic tool, as well as the level of agreement between trained lab scientists and CHEWs using the Foldscope.
To assess community feasibility of implementation, and opportunities for educational interventions for community health extension workers (CHEWs).
To assess acceptability and barriers encountered using the Foldscope in this clinical setting vs. conventional methods, as measured by focused group discussions (FGDs), structured in-depth interviews, and key-informant interviews (KIIs) with community leaders and current control effort leaders.
Methods
Study Design
This is a mixed methods cross-sectional study aimed at evaluating Foldscope-based microscopy against conventional diagnostic methods. All samples will be examined with the current gold standard in addition to the experimental process. It will also incorporate qualitative research components to assess community perceptions and implementation feasibility.
Study Area
This study will be conducted in Ogun State, Nigeria, specifically within the Imala Odo and Imala communities near Oyan River Dam to begin with. These communities have been selected due to their varying prevalence rates of schistosomiasis, with Imala Odo showing high prevalence (greater than 90% from unpublished reports) and Imala showing decreasing prevalence. The study will be conducted in rural communities within two local government areas in Ogun State. 3.3 Study Population The study will involve three distinct populations:
- Community members for diagnostic testing:
- Individuals aged 5 years or older with a history of freshwater exposure, recent travel from endemic areas, or hematuria/urinary symptoms
- Must be able to provide informed consent (or guardian consent for minors)
- Capable of providing a urine sample of at least 30 mLs
- Healthcare workers for feasibility assessment:
- Community health extension workers (CHEWs), lab scientists, technicians, nurses, or other clinicians
- Willing to participate in both the diagnostic testing phase and the qualitative evaluation phase
- Key stakeholders for acceptability assessment:
- Adults residing in rural communities in the study area
- CHEWs or clinicians from the study communities
- Other stakeholders with experience in schistosomiasis control (State & Local NTD coordinators, Medical Officers of Health, lab scientists or technicians)
- Must have been involved with schistosomiasis control efforts in the past
The project will assess diagnostic accuracy, community acceptability, and feasibility of implementation of this Foldscope-based microscope diagnostic process through collaboration with local community health extension workers (CHEWs) and volunteers.
The study will compare Foldscope-based microscopy workflow with conventional methods, focusing on the effectiveness and accuracy of this diagnostic tool paired with a reusable microfluidic device for trapping eggs in urine. Additionally, we will measure feasibility and community acceptability using a mixed-methods approach including focus group discussions and key informant interviews.
The research will be conducted in selected rural communities near the Oyan River Dam in Ogun State, with a sample size of 365 participants. The study employs a cross-sectional design with both quantitative and qualitative components to evaluate the diagnostic tool's performance.
Challenges
One problem could be integrating into existing work
Local scholars point to a gap between policy-making and control measures for schistosomiasis, as well as a lack of clarity about the number of people affected by S. haematobium infection in endemic areas, making epidemiological data difficult to determine (Ezeh et al., 2019).
However, we are honored to be in contact with the National Coordinator for Schistosomiasis Control in Nigeria, Ms. Imaobong Umah, who will remain informed as the study progresses to see if elements can be incorporated into control efforts.
We are also so fortunate to be collaborating with the Ogun State NTD coordinator, Dr. Soneye Islamiat.
We hope that by collaborating with over 5 academic mentors based in Ogun State, and directly working with government leadership focused on tackling schistosomiasis, we can integrate into existing control efforts successfully.
Pre Analysis Plan
Diagnostic Accuracy Data
The following metrics will be calculated using a 2×2 contingency table in GraphPad Prism:
Sensitivity = (TP/(TP + FN)) * 100
Specificity = (TN/(TN + FP)) * 100
PPV = (TP/(TP + FP)) * 100
NPV = (TN/(TN + FN)) * 100
Accuracy = (TP + TN)/(TP + TN + FP + FN) * 100
Kappa statistic (κ) = (Po - Pe)/(1 - Pe)
McNemar's test will be applied to compare performance between methods
Level of agreement between trained lab scientists and CHEWs will be assessed
rism:
Gold Standard | Foldscope Positive | Foldscope Negative | Total |
Positive (True Cases) | TP (True Positives) | FN (False Negatives) | TP + FN |
Negative (Non-Cases) | FP (False Positives) | TN (True Negatives) | FP + TN |
Total | TP + FP | FN + TN | N (Total Cases) |
● Kappa statistics will be used to determine the level of agreement between the Foldscope and the gold standard diagnostic approach.
● McNemar’s test will be applied to compare the performance of Foldscope versus gold standard microscopy.
Equations:
Sensitivity = (TP/(TP + FN)) * 100
Specificity = (TN/(TN + FP)) * 100
PPV = (TP/(TP + FP)) * 100
NPV = (TN/(TN + FN)) * 100
Accuracy = (TP + TN)/(TP + TN + FP + FN) * 100
κ = (Po - Pe)/(1 - Pe)
Calculations:
1. Sensitivity (True Positive Rate)
Sensitivity = (TP/(TP + FN)) * 100
Measures the proportion of true infections correctly identified by the Foldscope.
2. Specificity (True Negative Rate)
Specificity = (TN/(TN + FP)) * 100
Measures the proportion of uninfected individuals correctly identified as negative.
3. Positive Predictive Value (PPV)
PPV = (TP/(TP + FP)) * 100
Indicates the likelihood that a positive Foldscope result truly represents an infection.
4. Negative Predictive Value (NPV)
NPV = (TN/(TN + FN)) * 100
Indicates the likelihood that a negative Foldscope result truly represents an absence of infection.
5. Diagnostic Accuracy
Accuracy = (TP + TN)/(TP + TN + FP + FN) * 100
Represents the overall proportion of correctly classified cases.
6. Agreement (Kappa Statistic, κ)
κ = (Po - Pe)/(1 - Pe)
Where:
● PoPo = Observed Agreement (proportion of TP and TN combined)
● PePe = Expected Agreement due to chance
7. McNemar’s Test
● Used to compare the Foldscope's performance against the gold standard, testing whether the proportion of false positives and false negatives differs significantly.
All calculations will be performed using GraphPad Prism's Contingency Table and Agreement Analysis tools.
3.7.2 Qualitative Data Analysis
A thematic analysis of qualitative data will be conducted to explore perceived feasibility, acceptability, and barriers to implementing Foldscope-based diagnostics in community settings. Dedoose software will be used to facilitate coding, categorization, and pattern recognition in transcribed focus group discussions (FGDs), key informant interviews (KIIs), and structured interviews with community health extension workers (CHEWs) and other stakeholders. A deductive and inductive coding approach will be applied, incorporating predefined themes (e.g., usability, training needs, perceived accuracy) while allowing for emergent themes identified during coding. Coding reliability will be enhanced through inter-rater agreement, with discrepancies resolved through discussion. Stakeholder perspectives (e.g., CHEWs vs. community members) will be compared to identify variation in diagnostic feasibility and acceptability. Sentiment analysis will be performed to assess overall attitudes toward Foldscope implementation. Findings from FGDs and KIIs will be triangulated with diagnostic accuracy results to explore how perceived usability and feasibility correlate with Foldscope performance metrics. Descriptive statistics (e.g., frequency of themes, coding matrices) will be used to quantify qualitative findings where applicable. This approach will provide a comprehensive understanding of diagnostic implementation challenges and inform future scale-up strategies for community-based schistosomiasis control.
Protocols
Browse the protocols that are part of the experimental methods.
