Ideal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing platforms must be simple, accessible, and timely to ensure that symptomatic and exposed individuals are tested, positive results are identified, and isolation, quarantine, and contact tracing begin as soon as possible. Many children remain unvaccinated and, as other respiratory viruses surge, families have a pressing need for reliable and practical SARS-CoV-2 testing options.
Point-of-care rapid antigen SARS-CoV-2 tests address many of the challenges associated with real-time reverse transcription–polymerase chain reaction by offering the convenience of in-home testing for individuals (including parents), tolerability (anterior nasal swab), and rapid results (within 15 minutes).1 SARS-CoV-2 antigen test performance data suggest lower sensitivity when performed by nonhealth care professionals2 ; however, limited information exists on specific testing barriers parents face.
Identifying in-home testing pitfalls and strategies that facilitate high-quality testing is essential to inform test kit design and result follow-up. We applied hierarchical task analysis (HTA) to (1) model the task of in-home rapid antigen testing by parents, (2) identify potential failure modes, and (3) identify and categorize strategies used to address potential failure modes.
Methods
Participants were enrolled as part of a larger study aimed at increasing safe return to school for children with complex medical conditions.3 Participants were parents/caregivers of children enrolled in the University of Wisconsin’s Pediatric Complex Care Program (cohort average of 5 affected organ systems, 7 subspecialists, 10 scheduled medications, and 3 medical devices).4
The BinaxNOW Antigen Self-Test (Abbott) is a point-of-care, lateral flow immunoassay intended for the qualitative detection of the SARS-CoV-2 nucleocapsid protein antigen in direct anterior nasal swabs (symptomatic testing sensitivity range; 57%–74%; specificity range = 99.0%–100%).2,5,6
We conducted a contextual inquiry over video conferencing software to observe parents testing their children in their home environment. Contextual inquiry is a design research method that pairs observation with opportunistic questioning with the goal of uncovering details implicit in how people approach and conduct tasks.7 Sessions were recorded, transcribed, then analyzed by using team-based content analysis.8,9 HTA is a Human Factors method used to decompose a task into actions that are required to meet the overall objective of the task. By combining Human Factors expertise and protocol comparison, the resultant HTA informs task redesign by pointing to potential failure modes. We applied HTA to visualize the primary steps and secondary subtasks required to complete an in-home test. Potential failure modes and associated family-generated strategies were identified through the HTA by comparing the task as prescribed by the manufacturer and as performed by the family.3,10
Results
In July 2021, we enrolled 20 caregivers with an average age of 40 years (range = 32–59) who mostly identified as women (90%).
HTA revealed that in-home testing required 14 primary steps, 10 of which required subtasks, for a total of 44 steps achieving 3 subgoals (Fig 1). Fifteen potential failure modes were identified and were addressed with 29 strategies (Table 1).
Hierarchical task analysis of rapid antigen point-of-care SARS-CoV-2 test conducted by families of children with medical complexity. Shaded boxes indicate steps that have associated potential failure modes, lettered for reference in Table 1.
Hierarchical task analysis of rapid antigen point-of-care SARS-CoV-2 test conducted by families of children with medical complexity. Shaded boxes indicate steps that have associated potential failure modes, lettered for reference in Table 1.
Potential Failure Modes With Associated Strategies Used by Families to Overcome Them
| Potential Failure Modes | Strategies Used by Families to Overcome Failure Mode |
|---|---|
| A. Remember to conduct the test | Plan to do test as part of a preestablished routine |
| Set alarm or reminder | |
| Leave testing materials in line of sight (eg, on the kitchen table) | |
| B. Remember in which order to do the steps of the test | Refer to instructions while conducting the test |
| C. Cannot locate testing materials | Keep all materials in original box |
| Keep all materials in a designated location (eg, kitchen cabinet, desk drawer, supply drawer in child’s room, etc) | |
| D. Perforation on testing card package is small and hard to see/find | Keep scissors with materials and use those to open testing card package |
| E. Child or pet knocks testing card off surface | Set up testing card in a carefully selected location (eg, out of the child’s reach, on a high countertop, within eyesight, etc) |
| F. Cannot tell if there were 6 drops administered | — |
| G. Cannot remember how many drops to use | Write “6” on the bottle to cue use of 6 drops |
| H. Cannot tell which end is the swab end versus the handle end when opening, potential for contamination | — |
| I. Child does not like swabbing | Do swab while child is sleeping |
| Explain testing steps to the child verbally | |
| Have child do swab themselves (while coaching them, eg, “swirl it like you’re swirling your French fries in ketchup”) | |
| Keep child in a comfortable/distracting setting (eg, watching TV, counting, singing, etc) | |
| Have child in a chair that supports child’s head and neck to prevent bucking | |
| Ask child which nostril to swab first | |
| Have another caregiver help restrain the child during swabbing | |
| Model test swabbing on oneself first | |
| Distinguish the test explicitly from a deep nasal swab | |
| J. Fear of not getting enough sample | Do more circles in each nostril |
| Observe swab to see if it looks wet | |
| K. Sticker can be hard to peel off | Peel sticker tab off before swabbing (so that both hands are free) |
| L. Remember to go back to read results after 15 min and before 30 min | Set timer (eg, using smart home system, stand-alone timer, or phone) |
| Sit and wait 15 min in front of the card | |
| Place the test card in a location to cue reading it in 15 min (eg, next to them at their desk) | |
| Write time of test administration onto the testing card | |
| Read results before 15 min pass | |
| M. Confuse testing cards (if conducting test on >1 person) | Write name on the testing card |
| N. Read the lines because of poor vision | Use zoom feature on phone camera to observe results |
| O. Remember to record the results | Record test date and details while waiting and place the recording sheet next to the test card to cue recording results |
| Potential Failure Modes | Strategies Used by Families to Overcome Failure Mode |
|---|---|
| A. Remember to conduct the test | Plan to do test as part of a preestablished routine |
| Set alarm or reminder | |
| Leave testing materials in line of sight (eg, on the kitchen table) | |
| B. Remember in which order to do the steps of the test | Refer to instructions while conducting the test |
| C. Cannot locate testing materials | Keep all materials in original box |
| Keep all materials in a designated location (eg, kitchen cabinet, desk drawer, supply drawer in child’s room, etc) | |
| D. Perforation on testing card package is small and hard to see/find | Keep scissors with materials and use those to open testing card package |
| E. Child or pet knocks testing card off surface | Set up testing card in a carefully selected location (eg, out of the child’s reach, on a high countertop, within eyesight, etc) |
| F. Cannot tell if there were 6 drops administered | — |
| G. Cannot remember how many drops to use | Write “6” on the bottle to cue use of 6 drops |
| H. Cannot tell which end is the swab end versus the handle end when opening, potential for contamination | — |
| I. Child does not like swabbing | Do swab while child is sleeping |
| Explain testing steps to the child verbally | |
| Have child do swab themselves (while coaching them, eg, “swirl it like you’re swirling your French fries in ketchup”) | |
| Keep child in a comfortable/distracting setting (eg, watching TV, counting, singing, etc) | |
| Have child in a chair that supports child’s head and neck to prevent bucking | |
| Ask child which nostril to swab first | |
| Have another caregiver help restrain the child during swabbing | |
| Model test swabbing on oneself first | |
| Distinguish the test explicitly from a deep nasal swab | |
| J. Fear of not getting enough sample | Do more circles in each nostril |
| Observe swab to see if it looks wet | |
| K. Sticker can be hard to peel off | Peel sticker tab off before swabbing (so that both hands are free) |
| L. Remember to go back to read results after 15 min and before 30 min | Set timer (eg, using smart home system, stand-alone timer, or phone) |
| Sit and wait 15 min in front of the card | |
| Place the test card in a location to cue reading it in 15 min (eg, next to them at their desk) | |
| Write time of test administration onto the testing card | |
| Read results before 15 min pass | |
| M. Confuse testing cards (if conducting test on >1 person) | Write name on the testing card |
| N. Read the lines because of poor vision | Use zoom feature on phone camera to observe results |
| O. Remember to record the results | Record test date and details while waiting and place the recording sheet next to the test card to cue recording results |
Discussion
In-home testing requires multiple steps that can be vulnerable to failure. Although families developed strategies to address failure modes, the influence of these strategies on test sensitivity and specificity is unknown.
Rapid antigen tests are challenged by lower than ideal sensitivity; they are influenced by test timing, frequency, and testing procedures.2,5 The failure modes uncovered may contribute to sensitivity discrepancies observed between health care and nonhealth care professionals. Findings can be used by manufacturers to update instructional materials and test kit designs (Supplemental Table 2). For example, addressing failure modes F and G by including only the amount of reagent needed or designing the test card (subtask 1.4) such that only the correct amount of reagent can be added. In addition, improved visual design on packaging could address failure modes D and H by directing attention to the test card packaging’s perforation and to the swab packaging’s peelable end, respectively.
Our findings uncover vulnerable areas that could be useful to clinicians. For example, when speaking with patients, clinicians may probe about failure modes to guide proper testing procedures. Knowing how to evaluate high-quality test procedures will bolster confidence among those depending on reliable results (eg, clinicians, employers, school administrators, etc). For example, clinicians could work with families to alert them to potential challenges and advise on any strategies that may compromise test performance.
Our findings may not generalize to all populations. Families of children with medical complexity have familiarity with medical care. Replicating this study in other populations (ie, caregivers having disabilities) could identify additional failure modes. We used 1 point-of-care SARS-CoV-2 antigen testing platform.
The many steps, potential failure modes, and strategies involved with in-home rapid antigen SARS-CoV-2 testing by families may influence test performance. Given growing direct-to-consumer test availability, similar studies are needed to quantify failure rates and ensure appropriate conclusions are drawn from reported results.
Acknowledgments
The authors would like to extend our gratitude to the families who participated in this study and the ReSET study overall. Your generosity and insights are invaluable as we aim to better design in-home testing platforms.
Ms Barton led data collection, analysis, and interpretation and drafted the initial manuscript; Dr Werner contributed to study conceptualization and design and supported data analysis and interpretation; Ms Morgen participated in data collection and analysis; Drs DeMuri, Kelly, and Wald and Ms Warner and Ms Katz contributed to study design; Dr Coller conceptualized and designed the study, contributed to data analysis and interpretation, and provided study supervision; and all authors critically reviewed and revised the manuscript, approved the final manuscript as submitted, and agree to be accountable for all aspects of the work.
FUNDING: This research was, in part, funded by the National Institutes of Health (NIH) Agreement No. 1 OT2 HD107558-01(award number OT2 HD107558). The project was additionally supported by the Clinical and Translational Science Award program, through the NIH National Center for Advancing Translational Sciences, grant UL1TR002373. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the NIH. Funded by the National Institutes of Health (NIH).
CONFLICT OF INTEREST DISCLOSURES: The authors have indicated they have no potential conflicts of interest to disclose.
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