Technical Assistance Documents

8.1 Legibility

Issue

• Some test instructions use mixed or hard-to-read typefaces, fonts, and other text features.
• Entirely capitalized words are communicated by screen readers letter-by-letter, making interpretation challenging.

Recommendation

• Consistently use an easy-to-read, sans serif typeface such as Arial, Calibri, Helvetica, Verdana, etc.
• Do not use italicized text, which reduces legibility for some users. Emphasize important content via boldface text.
• Do not capitalize entire words. Emphasize important content via text labels (e.g., ‘Warning’, ‘Note’).
• Avoid underlining, except for clickable links.

Issue

• Content is displayed such that it is challenging to distinguish key and supporting information.
• Expiration dates and QR codes are small and difficult to locate.
• Presenting critical information without text labels creates issues with OCR interpretation (e.g., an expiration date presented as a number string may not be recognized as a date).

Recommendation

• Present key information in large and/or boldface font (minimum 14 point, ideally 18 point or larger).
• Include a QR code linking to digital instructions sized 0.8 inches (20.3 mm) square or larger to align with current industry practice.
• Present expiration date with abbreviated or spelled-out month, numerical day and year (e.g., Oct 12, 2022), as well as in unique device identifier (UDI) format (e.g., 2022-10-12). Ideally, identify expiration date via text label (e.g., ‘Expiration Date, ‘Use before’ or ‘Do not use after.’).
• Label critical information such as the product website, customer service phone number, and customer service email with text to provide context to users employing OCR applications.

Issue

Information may be provided with poor color contrast, making it challenging to perceive key information.

Recommendation

Color contrast should allow for clear differentiation between the text and background. Provide a minimum contrast ratio of 4.5:1 for 14 point or smaller font and 3:1 for larger font. Contrast ratio compares relative luminance of text and background color and can be measured using free color contrast checker tools like TPGi’s Colour Contrast Analyser (CCA). [12]

8.2 Readability and Layout

Issue

• Steps requiring multiple actions or tasks can be challenging to comprehend and follow.
• Too much information can be presented in a format that is difficult to follow with individual steps consuming variable amounts of page space.

Recommendation

• Provide a single, actionable task for each step.
• Break text describing workflow steps into block paragraphs of comparable length, using bullet points where possible.

Issue

• Blocks of text may be presented in different layouts, with some sequences of blocks reading left to right and others top to bottom, making following along cumbersome.
• Large, unbroken blocks of text make digesting information difficult, and wide columns make some users physically dizzy.

Recommendation

• Use the flow scheme shown above with columns arranged left to right. Two columns on 8.5 x 11 inches (216 x 279 mm) U.S. letter size paper in portrait orientation, or four columns on 11 x 17 inches (279 x 432 mm) tabloid size paper in landscape orientation works well.
• Text columns should be equal width and include proportioned column gutters.

Issue

Warnings are presented inconsistently making it hard to locate them or allow the critical warnings to attract the appropriate amount of attention.

Recommendation

Critical warnings (e.g., those where user error is associated with the greatest risk of an invalid test result) should be communicated in a consistent manner (e.g., with a red warning symbol and boldface font in a text box callout).

8.3 Language

• Plain Language
• Descriptive Language
• Alternative Text
• Braille

Plain Language

Plain language is a process for developing a communication (such as a printed document, webpage, or mobile application screen) that allows intended users to “find what they need, understand what they find, and use what they find to meet their needs”. [13] [14]

Plain language is the process of developing user-appropriate information. It includes purpose, structure, expression, design, and evaluation.

Purpose: identify and describe the target users and the communication goals.

• Develop clear information goals.
• Select document content with the target users in mind.
• Align content structure and design to target users’ needs, skills, and interests
• Use target user information, such as reading level, experience, and style preferences, when developing content.

Structure: group and present content with a clear rationale to guide the user.

• Organize the document with ease of access in mind.
• Use familiar structures to make document navigation logical and relatable.
• Create balance in information delivery: not too lengthy, in order to maintain attention, and not too short, in order to provide sufficient context.
• Create document flow by grouping related content and using descriptive headers.
• Divide document sections clearly and consistently.
• Limit header levels to three or fewer.
• Present sequential items in a numbered list rather than a bulleted list.
• Use parallel structures for equivalent content.

Expression: select words, sentence structure, and overall organization for logic and empathy to promote comprehension and engagement.

• Use terminology specific to the end user.
• Provide the lay user with an explanation of unfamiliar or technical terms.
• Incorporate descriptive language where possible (see 8.3 Language • Descriptive Language).
• Mix sentence length, with an average of 12-15 words per sentence.
• Lead paragraphs with key information.
• Create coherence by grouping related ideas, with transition words between sections when appropriate.
• Use a bias-free conversational tone, focusing on positive outcomes and desired behaviors.
• Use warnings to convey potential negative outcomes
• Match hyperlinked text to the landing webpage titles.

Design: apply information design to enhance legibility, readability, and comprehension.

• Ensure document design elements support the message as well as user comprehension.
• Use typography to support legibility (see 8.1 Legibility).
• Use layout to support readability.
• Use whitespace to highlight information organization.
• Use clear and meaningful illustrations to support comprehension.
• Use illustrations of desired behaviors and results, when possible.
• Omit unnecessary elements that create distraction.

Evaluation: develop and test wording, structure, and design with end users.

• Elicit input from target users to determine needs, preferences, usability, and satisfaction before, during, and after development of a document. (See 5. Engaging End User Advocacy Groups and 7. Assessing Usability).
• Develop information with input from target users.
• Select valid methods for measuring understanding and actionability of information.
• Measure information clarity, accuracy, and usefulness with the target users.
• Ask target users if it is clear who the information is for and what the purpose is.
• Ask target users to paraphrase key concepts and show how they would find information in the document.
• Compare before and after versions of the information to confirm plain language improvement.

Descriptive Language

Language should be descriptive and provide nonvisual points of reference and instruction for better end user comprehension. In general, word count should be minimized while still providing effective descriptions. Ideally, descriptive language should be included in body text of test instructions, but additional supporting information may be provided via alt text or ‘More Info’ redirects.

Issue

• Certain practices create unnecessary ambiguity, such as referring to components or features generally as “this” or “that” and using abbreviations/ acronyms.
• Test instructions sometimes refer to components and features inconsistently.
• Component descriptions lack sufficient detail.

Recommendation

• Avoid using pronouns.
• Avoid using abbreviations or acronyms. If necessary, clearly define the abbreviation or acronym at first instance and use consistently thereafter.
• Use the same name for a component or feature throughout the test instructions and labels on components or packaging.
• Components should be described with both tactile and visual references. Terminology used should focus on differentiating components by feel, such as through shape, texture, material, or weight. Example descriptors:
• Shape: rectangular, cylindrical, long, thin, wide, flat, narrow, tall
• Texture: smooth, rough, soft, hard, raised
• Material: paper, plastic, foil, metal
• Weight: heavy, lightweight

Issue

Color is used and described ineffectively.

Recommendation

• Color should be used to refer to easily distinguishable areas, and reference to color should be accompanied by a nonvisual descriptor (e.g., ribbed red dropper cap, rectangular silver pouch).
• Avoid using colors that may be imperceptible or indistinguishable. [15]
• Describe each color by name and relative tone (e.g., brighter), if applicable.

Issue

• The order of descriptive information may prevent users from accurately locating an item.
• There is often no written description of where the results window is located, or where control and test lines will appear within it.

Recommendation

• Start with a brief description of how the feature will feel and follow with details of location progressing from broad to specific to yield one unique location. Conclude with a secondary visual descriptor.
• Example: “The notch is a small slit in the edge of the flat, foil pouch on the long side near one end. It is marked with a black arrow.”
• Description composition: [feature name = notch] [feature tactile reference = small slit in edge] [highest level location reference = flat, foil pouch] [increasingly specific location = long side, near one end] [secondary visual descriptor = black arrow].
• For results interpretation, describe the relative location of the result indicators.
• Example: “The results window is positioned closest to the rectangular end of the cassette. On the test strip secured in the results window, the control line is positioned closest to the rectangular end of the cassette and the test line is positioned closest to the rounded end of the cassette.”

Alternative Text

Alternative (alt) text is text included in webpage HTML code or in a digital file tag structure that describes non-text media such as graphs, charts, and non-decorative images. It provides equal access for those viewing content with a braille display or screen reader.

Issue

• Alt text may inadequately describe the content of an illustration.
• Alt text may inadequately convey information in visuals.
• Alt text length varies.
• Alt text may be overly informal.

Recommendation

• Alt text should build on the copy, translating visual content and providing supporting detail without being redundant. Together, alt text and instructional copy should enable a user to understand and complete the test workflow without visual references.
• Example: “an illustration of a swab breaking in half with the tip in a tube” would be better written as “with the swab tip in the tube, the swab can be broken in half at a notch in the middle of the handle.”
• Reiterate critical warnings provided in illustrations where the critical warning text is not included in the copy and digital read order.
• Generally, alt text should be kept to one to two sentences, though complex visuals may require longer alt text.
• If alt text is lengthy, consider incorporating it as part of the body text of test instructions instead.
• Maintain correct grammar and punctuation in alt text.

Braille

Braille is a tactile reading and writing system in which raised dots represent the letters of the alphabet, numbers, and symbols. [16] Braille serves as one approach to capturing and conveying the same level of detail provided in text content.

Braille is an inherently physical medium traditionally produced using braille “printers” that emboss paper capable of retaining raised dots. Braille has a fixed minimum character size roughly comparable to 28-point font. One traditional print page of text typically transcribes to multiple braille pages, depending on the character count and formatting. Particularly dense, information-packed documents could easily transcribe into significantly longer paper braille documents, especially if they include complex content such as graphs, charts, or non-decorative images. It is desirable to make paper braille instructions available to customers upon request.

Creating web-based, digitally accessible documents is a cost-effective method for manufacturers to provide additional access to braille. Braille displays enable users to access digital content through braille instead of audio only, so they can obtain the rich information embedded in text including capitalization, typographical emphasis, spacing, and punctuation. [16] Digital formats that can be readily converted to braille using assistive technology include:

• An accessible webpage with HTML content that is compatible with screen readers and braille devices.
• An accessible PDF document available for download.
• A braille-ready file (.brf) aimed at users who have braille devices but do not regularly make use of computers, smartphones, and/or the Internet.

Note: Product labeling should adequately inform users of the instruction formats that are available and how to obtain them.

Issue

Photos contain extra, unnecessary information making them difficult to interpret, especially when printed on an embossing printer.

Recommendation

• Use line drawings with perspective instead of photos.
• Use varying line weights to distinguish detail and accent features (e.g., 1 point – 1.5 point for lines and 3 point – 4 point for accent features).

Issue

It can be difficult to interpret 2D drawings, especially those with thin lines, low contrast, or lower image quality or sharpness.

Recommendation

Use high-quality, high-contrast, thick line drawings with shading, as appropriate.

Issue

Illustrations without context do not inform readers about relative component size and force the reader to guess how components are to be utilized.

Recommendation

• Use illustrations that provide physical context for the reader (e.g., include hands, noses).
• Keep illustrations simple, using only enough detail on features to clarify their purpose (e.g., a head does not need to include hair).

Issue

Symbols are hard to understand if they are arbitrarily chosen or region-specific. Their meaning may not be obvious to the reader.

Recommendation

Use unambiguous and globally accepted symbols. Follow the ISO 15223-1:2021 standard for symbols used on medical device packaging. [17] Include text labeling immediately adjacent to symbols (e.g., ‘Expiration Date’ next to hourglass symbol).

Issue

Illustrations that are not presented with details that match the actual component may cause confusion.

Recommendation

• Make sure illustrations match the actual appearance of the components (e.g., if a cap is gray, do not illustrate in white; if the cassette has text or other markings on it, include these in illustrations).
• Use grayscale as appropriate and retain outlining of gray features.

Issue

Illustrations with elements that are overlapping and appear to be floating in space without a composite reference are difficult to decipher.

Recommendation

For exploded view illustrations:

• include a composite reference image;
• ensure exploded elements are not overlapping;
• utilize arrows to indicate each exploded element’s position in the composite reference image; and
• utilize solid arrows between exploded elements to signify stacking.

Issue

Large instruction panels with folds can result in text crossing over folds. Same-topic information may be split across front and back panels, resulting in reduced readability.

Recommendation

• Ensure paper creases only appear in text column gutters so it is easier to scan parts of a folded document for OCR.
• Place all information needed to run the test on one side of the paper or card. The other side can be used for supporting information.

Issue

• It can be difficult to physically place test instructions adjacent to test components due to size or material, which makes it difficult to reference instructions while using the test.
• Tests with fluid can result in spills that may deteriorate less robust instructional materials.

Recommendation

• Provide test instructions in a form that allows placement adjacent to a test on a table.
• Consider that lighter paper weights allow instructions to lay flat. Use materials that can withstand some amount of liquid spill. If coatings are used, limit reflectivity.

Issue

Paper (or similar) documents may be provided in an incompatible format for assistive technology. Pages or panels may be too large for flatbed scanners and smartphone OCR. Multiple panels without numbering make it difficult to navigate from page to page.

Recommendation

• Provide paper (or similar) documents in panels no larger than 8.5 x 11 inches (216 x 279 mm) U.S. letter size to facilitate flatbed scanning.
• Use page numbers for multiple panels on the front and back.

Issue

Physical instructions lack tactile, page orientation cues.

Recommendation

Include a tactile page orientation cue, typically a clipped upper right corner, on physical instructions.

8.6 Digital Embodiment

• Operating System Compatibility
• Assistive Technology Compatibility
• User Interface and Experience Features
• Standalone Audio Instructions
• Interactive Voice Response (IVR) System
• Video Tutorial

Operating System Compatibility

The ability for content to be recognized and understood by computer, smartphone, and tablet device operating systems (OS) and accessibility tools is vital for ensuring user access to information about the test.

Issue

• Test instructions are provided in a format that is not compatible with computer, smartphone, or tablet device OS and accessibility tools
• Some features that provide feedback (e.g., auditory and haptic) can compromise user’s privacy and others (e.g., bright mode) can cause eye strain.
• Applications sometimes require users to enter personal information to sign in before providing access or the ability to receive test results.

Recommendation

• Ensure application recognizes and supports native device OS accessibility settings. Custom video playback tools are not desirable.
• Recognize and apply the user’s system-wide accessibility preferences (e.g., font sizing or inverted colors) and provide an in-application option to turn auditory/haptic feedback on or off.
• Enable dark mode option.
• If the application requires data entry for sign-in/ results reporting:
• Enable autofill and/or single sign-on (SSO) through Google, Apple, Facebook, etc.
• Clarify which data entry fields are required versus optional.
• Save partial data (e.g., create a user profile) so user does not have to input data again for repeat testing.
• Ensure that all data entry fields are assigned screen reader-compatible labels.

Assistive Technology Compatibility

Digital instructions should be provided on a website that conforms to WCAG 2.1 AA standard and has undergone rigorous testing with assistive technology such as screen readers and voice dictation software. [18]

The website should be accessible via QR code and a plain text URL. Test-specific companion applications are another method for users to access digital test instructions.

Issue

Test instructions are provided in a format that is not web or mobile accessible and/or is incompatible with native device operating system (OS) accessibility features.

Recommendation

• Digital test instructions should be housed on a webpage that applies responsive web design.
• Audit all relevant webpages for WCAG 2.1 AA compliance with experienced digital accessibility professionals to ensure compatibility with assistive technology. Complete a follow-up audit for WCAG 2.1 AA compliance following any remediation efforts.
• Reference and implement best practices for making application content web accessible and mobile accessible.[19] [20]
• Ensure the test instructions are available as a PDF that conforms to Section 508, WCAG 2.1 AA, and PDF/ Universal Accessibility (UA) standards. [21] Note that while Section 508 compliance indicates an accessible digital file format, it does not confirm language is accessible. Content requires a separate and thorough review (see 8.3 Language).
• Ensure all images have meaningful, descriptive alt text (see that 8.3 Language • Alternative Text) supports nonvisual discernment of kit components (e.g., by shape, size, feel).
• Ensure all form fields, buttons, and other interactive elements have accessible names/labels.
• Provide a digital accessible information system (DAISY) format of the test instructions with sections and subsections defined in the file.
• Provide a direct link on the product website to a full digital version of the test instructions.

Issue

Not all digital test instructions are compatible with screen readers. Key elements are often coded incorrectly or in a format that screen readers cannot detect, meaning content may be out of order, incomplete, or incomprehensible. Test instructions may be provided in a format that is not compatible with use on a smartphone or tablet or that cannot be digested by native OS accessibility features.

Recommendation

Ensure digital test instructions are compatible with all commonly used screen reader and operating system combinations. Confirm both computer and mobile screen reader compatibility of every screen element (e.g., images, fields, buttons).

User Interface and Experience Features

The presence or absence of features in an application or web design can significantly impact usability and user satisfaction with the test. A small improvement in user interface design can have a major impact on the entire user experience.

Issue

Some important content can be missed with the use of a digital user interface if the content is not appropriately segmented.

Recommendation

• Provide pop-up messages for important content that remains on screen until user provides input to acknowledge the message.
• Errors, warnings, and success messages should not automatically disappear until the user acknowledges the message.

Standalone Audio Instructions

Audio may be the preferred mode for some users to receive test instructions. Designing the audio content is critical to providing a comprehensive understanding of the product.

Issue

• Audio test instructions are not always available.
• Audio test instructions alone are not always sufficient for full understanding.
• Audio test instructions, when available, can only be accessed indirectly (e.g., via a webpage).

Recommendation

• Audio test instructions should always utilize the copy and alt text as the script.
• Written instructions and alt text together should provide enough description of components and actions for understanding without visual reference.
• Audio test instructions should be available in easy-to-navigate formats.
• Use of professional human voice is preferred to create the audio, but clear text-to-speech (TTS) engines may be used as an alternative. Audio test instructions may be provided as part of a tutorial video (see 8.6 Digital Embodiment • Video Tutorial). Suitable file formats for standalone audio instructions include:
• Podcast type file (M4A) with all sections of the test instructions included as timestamped chapters or episodes. Alternative open file types that support meta data and navigational features may be used.
• DAISY audiobook file with sections of the test instructions included as chapters.
• Enable direct access to complete audio test instructions via radio frequency identification (RFID) tags on the outer box.
• En-Vision America’s ScripTalk and CVS Pharmacy’s Spoken Rx are examples of such services. [22] [23]

Interactive Voice Response (IVR) System

IVR systems can be used to connect users to instructions through a phone call. This is particularly useful for users who are less familiar with using web or mobile applications. Connecting users to test instructions via telephone allows them to use a well known, expected instruction format.

Issue

• Test instructions are not always available by phone.
• Audio test instructions made available via phone are not navigable by section and step.

Recommendation

• Provide audio test instructions via phone.
• Implement an IVR system where caller responds to prompts via button presses or spoken statements associated with actions, including navigation (e.g., continue to next step, repeat current step, return to previous step, return to main menu, connect to a live agent).

Video Tutorial

Videos can be an effective way to inform users about the product. They provide dynamic demonstrations to learners who prefer to process information visually and audibly. Executed well, they can also provide an improved audio instruction experience versus screen reading digital instructions.

Issue

• Video test instructions are not always provided on websites or applications.
• Some videos do not provide the ability to pause, rewind, or forward in discrete increments, making it challenging to jump to the step a user is trying to review.
• Visuals with actors completing steps can be challenging to follow due to issues with lighting and contrast and general visual complexity.
• An abbreviated version of a longer video allows users to skip the complete video and miss important steps.
• Automatically looping videos can be distracting and challenging to navigate.
• Closed captions are not always provided or are not properly synchronized.
• Audio description – description of a video’s visual elements – is not provided, not easy to locate, and/or does not provide sufficient nonvisual context.

Recommendation

• Make video test instructions available via the product website
• Confirm video player is accessible. [24] [25]
• Provide the ability to control video playback including pause/play, rewind, forward, replay from the beginning, scroll through time or advance incrementally, and switch to full screen mode.
• Use high-contrast 2D animations with perspective/ depth and appropriate fill instead of live action.
• Do not provide an abbreviated version of a longer video.
• Avoid looping videos and/or audio with no ability to pause.
• Ensure closed captions are provided and synchronized with the video and audio content. [26]
• If the video tutorial is embedded in an application, allow skipping the video after it has been viewed once.
• Consistent with providing alt text for 508 compliance of digital documents ( see 8.6 Digital Embodiment • Assistive Technology Compatibility), video must include complete audio description. Refer to Digital.gov’s “508 Accessible Videos – How to Make Audio Descriptions” for details. [27]
• Provide audio description within the main audio, or preferably, as an option enabled by the user. [28]
• Include timestamps on the player for easy navigation to specific sections (e.g., getting started, workflow, interpreting results). Use native device OS video controls.
• Ensure on-screen buttons conform to WCAG 2.2 success criterion 2.5.8. [29]

9. Physical Components

• 9.1 Outer Packaging
• 9.2 Kit
• 9.3 Swab
• 9.4 Fluid Vials and Sample Preparation
• 9.5 Cassette
• 9.6 Test Reader
• 9.7 Disposal

9.1 Outer Packaging

• Labeling
• Accessing Contents

Labeling

The outer box packaging is the initial introduction to any device, so labeling and interaction with the outer packaging should be carefully considered. Packaging typically conveys information through text, images, and symbols. Packaging can also convey information through shape and links to external information (e.g., QR codes).

Issue

Packages are often inadequately labeled and missing critical information.

Recommendation

Consider how the package might be displayed (e.g., on a shelf in a retail setting) and what information the user will find most useful.

Issue

• Outer box label information is presented without visual hierarchy.
• Outer box labeling is cluttered with excess information in a small font.

Recommendation

• Prioritize key information including brand name, device type, expiration date, links to test instructions, and customer service number by size and position. Ensure labeling complies with regulatory bodies’ requirements.
• Use minimum 14 point and ideally 18 point or larger font and legible sans serif typeface (e.g., Arial, Calibri, Helvetica, Verdana, etc.). Do not use decorative typefaces (e.g., Script, Slab).
• Use effective color contrast (see 8.1 Legibility).

Issue

• QR codes are often missing or insufficiently sized.
• Expiration date format is not recognizable by common OCR applications.

Recommendation

• Present QR codes in a size 0.8 inches (20.3 mm) square or larger to align with current industry practice.
• See 8.1 Legibility for guidance on expiration date formatting.

Issue

Outer packaging may make it difficult to find or access information.

Recommendation

Provide a tactile means for finding information (e.g., QR code on sticker or within a raised outline).

Accessing Contents

Opening and accessing contents of outer packaging requires a balance of competing needs:

• preventing unauthorized users from tampering with contents;
• ensuring the package is easy to open for all users; and
• protecting internal components.

Issue

• It can be challenging to find and remove small, clear, tamper-evident seals.
• Users may resort to external tools such as scissors to open a challenging package, which may result in damaged contents.
• Tearing open a package without removing the seal may result in damage to the package and the fluid vial holder if it is integrated into the outer box.

Recommendation

• The tamper-evident seal should be a contrasting color to the rest of the package.
• For easy removal without the use of external tools, the seal should include a grasp feature with sufficient graspable area (e.g., at least 0.5 inches [12.7 mm] square).
• Force required to remove a tamper-evident seal should not exceed 5 lbs. (22.2 N). [30]

Issue

It can be challenging to open a package when the only indication regarding top, bottom, front, and back is through visual, printed labeling.

Recommendation

Provide familiar tactile cues on the packaging indicating where a package should be opened (e.g., thumb cutout, overlapping flaps).

9.2 Kit

• Organization
• Internal Pouches

Organization

Test kits containing multiple components must identify the components, secure small components, and provide information about the order in which the components are to be used. Organizing package components thoughtfully can greatly enhance the user’s ability to complete the test. A tray is an optional accessory for organizing components and improving the user experience.

Issue

Internal, physical test instructions and key information can be difficult to find.

Recommendation

Provide legible (see 8.1 Legibility) test instructions face up as the first thing users encounter.

Issue

Packages can have multiple components and internal pouches loosely placed inside. When opened, the contents can fall out and be misplaced. The order in which internal pouches or components are meant to be opened is unclear.

Recommendation

• Place contents in an organized and/or fixed manner (e.g., tray, bag, card, box dividers, etc.), in clear order of use.
• If including a tray, provide ample finger clearance and gripping space/features (e.g., pull tabs) for removing the tray from the box and components from the tray.

Issue

Components in internal tray can be difficult to identify

Recommendation

Include high-contrast component text labels on internal tray.

Issue

There is a risk of unintentional spillage when the fluid vial holder in a tray is improperly positioned.

Recommendation

The fluid vial holder should be positioned strategically in the tray to prevent unintentional disruption.

Internal Pouches

Accessing internal components frequently requires opening secondary packaging. The user should be able to easily distinguish pouched components, identify where to open each pouch, and open pouches with less than 5 lbs. (22.2 N) force. [30] Design features such as grip areas, visual cues, and labeling play a pivotal role in usability of internal pouches.

Issue

Internal pouches that are similar in size, shape, and/or material, or insufficiently labeled, may be difficult to distinguish from one another.

Recommendation

• Ensure that each pouched component is tactilely discernible from others (e.g., distinct internal pouch shapes/sizes).
• Label internal pouches with component names or illustrations.

Issue

Internal pouches may be difficult to open.

Recommendation

• Pouches should contain a notch labeled with high- contrast text or an arrow indicating tear location.
• Incorporate textured grip areas

Issue

• Peel-apart pouches have layers that are challenging to differentiate and separate.
• Internal packaging may present a method for opening that exposes an area to contamination through touch.

Recommendation

• Include half-moon cutout in one of the peel-apart pouch layers or fold-over of one of the peel-apart pouch layers.
• Ensure the opening exposes a component part intended for touch (e.g., peel feature near swab handle rather than swab tip).

9.3 Swab

Issue

Swabs with no clear indications for handling may be contaminated by touch.

Recommendation

• Swab shaft should have identifiable features (e.g., textures) so that the user knows where to grasp, preventing sample contamination.
• Employ contrasting colors for the swab shaft and swab tip so they can be readily discerned.

Issue

Swabs have no indication for appropriate nostril insertion depth.

Recommendation

Incorporate a tactile feature on the swab to inform the user of the required depth of insertion.

9.4 Fluid Vials and Sample Preparation

Issue

Small caps and vials may be misplaced and are tricky to handle, creating a spill risk.

Recommendation

• Large caps and vials with identifiable features (e.g., color, shape) help improve handling.
• Attach caps to the fluid vial (e.g., with a living hinge).

Issue

Tests may require transferring buffer solution (e.g., reagent) into the extraction fluid vial, which increases the risk for incomplete transfer and/or spill.

Recommendation

Eliminate the need to transfer buffer solution when possible (e.g., by integrating a prefilled fluid vial and dropper cap).

Issue

• Fluid vials with stiff walls (e.g., thick plastic) make it hard to dispense liquid by squeezing.
• Short fluid vials may be difficult to grip or manipulate.
• Depending on material opacity, it may be difficult to visualize liquid dispensing.

Recommendation

• Make fluid vial walls thinner and more pliable, ensuring force to dispense liquid is less than 3.5 lbs. (15.6 N). [31]
• Vials should be at least 1.6 inches (40mm) long. [32]
• Construct fluid vials of see-through materials to allow clear visualization of contents.

Issue

Fluid vials may be unstable, making them difficult to set down during the testing process.

Recommendation

• Design fluid vials to ensure stability when set upright (e.g., integrated vial base, separate vial stand, vial stand punch-out in outer box).
• For a vial stand punch-out in the outer box, ensure force to puncture is less than 5 lbs. (22.2 N) , use high-contrast labeling to indicate location, size to ensure secure fluid vial fit, and position in a location that does not interfere with box use (e.g., at box edge). [30]

Issue

Narrow openings make it difficult to insert the swab into the fluid vial, which can result in the swab tip being touched and contaminated during insertion.

Recommendation

Widen or reshape (e.g., funnel) fluid vial opening so that the swab can be easily and safely inserted.

Issue

Tests may require physically supporting the fluid vial during sample agitation, increasing spill risk.

Recommendation

Incorporate fluid vial design features that reduce the force that needs to be applied during sample agitation or sample extraction (e.g., internal ribbing).

Issue

Counting drops delivered to the cassette sample well is challenging and creates potential for user error.

Recommendation

Design the test so that the complete volume in the fluid vial is used for analysis.

9.5 Cassette

Issue

• An indistinct cassette shape may make it challenging to correctly orient the device and identify features such as the sample well and results window.
• An indistinct shape may also make it challenging to correctly load the cassette into a test reader, if applicable.

Recommendation

• Design the cassette with distinguishing features (e.g., colors, shapes, textures) for easy identification and manipulation.
• Provide a keying feature so that the cassette can only be loaded into the test reader in the correct orientation.

Issue

• The location of the sample well and results window may be difficult to identify, especially by touch. This may lead to sample spills.
• The sample well and results window may be easily confused.

Recommendation

• If sample fluid transfer is required, incorporate features on the cassette that facilitate alignment or docking of the fluid vial and sample well (e.g., locking features, raised edges of sample well, contrasting color of sample well).
• The sample well and results window should be shaped differently and separated sufficiently.

Issue

An exposed sample well increases the risk of touch contamination, which may affect the test result.

Recommendation

Include features on the cassette that reduce likelihood of touch contamination (e.g., raised edges of sample well).

Issue

• Users may dispense an incorrect number of drops.
• Users may dispense drops in an incorrect location.

Recommendation

• If counting drops is required, include a high-contrast label on the cassette indicating the number of drops required.
• To facilitate identification of sample well location, include a 0.1 inch (3 mm) raised edge and/or a high-contrast outline.

9.6 Test Reader

Issue

The test reader shape may make orientation and identification of features (e.g., cassette insert area) challenging.

Recommendation

Design the test reader with distinguishing features (e.g., colors, shapes, textures) for easy orientation.

Issue

Physical buttons may be difficult to locate and activate.

Recommendation

• Ensure physical buttons are a minimum 0.5 inches (12.7 mm) wide and are spaced a minimum 0.7 inches (17.8 mm) center to center. [33]
• Physical button features (e.g., shape, edges) should be distinct.

Issue

• Test kits or instructions may not clearly indicate battery location.
• Batteries may be located in an area that is hard to reach.

Recommendation

• If applicable, include an on-device label with a tactile symbol to indicate battery location.
• Position batteries so that they can be easily accessed.

Issue

• Test kits or instructions may not clearly indicate battery access and removal method.
• Battery access doors may be difficult to remove due to small, hard-to-grip handles.

Recommendation

• Clearly label the access door to indicate removal method (e.g., tactile features).
• Implement familiar battery removal methods.
• Include features that can be manipulated without employing fine motor skills (e.g., pull tag, larger divot).

Issue

Some test readers only communicate status (e.g., power, rechargeable battery level, results available) visually.

Recommendation

Consider adding nonvisual indicators, such as audible and/or haptic feedback, to inform the user of test reader status. If using LED colors to indicate status, consider using multiple LED lights with spatial differentiation rather than a single LED light that changes colors.

Issue

Battery-powered test readers may not clearly indicate the correct orientation for loading batteries (e.g., how to position positive and negative battery terminals).

Recommendation

• Consider pre-loading batteries.
• Provide visual and tactile indicators of the correct orientation for loading batteries both on the battery access door and inside the battery compartment.
• Match existing consumer mental models about battery orientation to design (e.g., the negative battery terminal goes on a spring).

Issue

Smartphone-based readers may require specific placement of a component (e.g., in a camera frame) using only visual cues (e.g., on-screen tracking markers).

Recommendation

• Provide auditory/haptic device positioning and camera visibility feedback to the user (e.g., “test identified” or “failed - move closer”; or “failed - increase brightness”).
• Implement automated image correction.
• Leverage native smartphone camera application accessibility controls.

Issue

Reusable test readers collect dirt and grime in hard-to-reach places.

Recommendation

If the test reader is reusable rather than disposable, design it with cleanability in mind. Eliminate crevices to facilitate easy wipe down.

9.7 Disposal

Issue

• Tests kits may not indicate which components are disposable.
• Test kits may not indicate appropriate methods for disposal (e.g., household waste, recycling, hazardous waste, etc.).
• Devices with batteries may not indicate the need for removal prior to disposal.

Recommendation

• Provide clear disposal labeling and instructions.
• If applicable, provide clear instructions for battery removal before disposal.

10. Test Procedure

• 10.1 Bluetooth Pairing
• 10.2 Test Analysis
• 10.3 Results Communication

10.1 Bluetooth Pairing

Issue

• Some tests require Bluetooth pairing (connecting a smartphone and another device) to analyze and communicate results. Common pairing methods only provide visual feedback on pairing status.
• Some pairing requires devices to be placed in proximity with inadequate feedback on whether the devices are in or out of range.

Recommendation

• Provide multi-modal, clear feedback on pairing status (e.g., audible and/or haptic feedback).
• If devices are required to be placed a specific distance from each other, provide device positioning recognition to the user.

10.2 Test Analysis

Issue

• There is no clear feedback, visual or otherwise, indicating that the sample has been properly entered into the device and test analysis is underway.
• Most tests only indicate visually that the sample has completed processing and results are available.

Recommendation

• Provide visual, auditory, and/or haptic cues letting the user know that the sample has been properly entered into the device and is processing.
• In addition to visual cues, consider adding auditory and/or haptic indications that results are available.

10.3 Results Communication

Issue

• Control and/or test lines on the test strip within the cassette can be very faint.
• Result labeling on the cassette may be too small or low contrast and may not align exactly with the associated position of the control and test lines in the results window.
• Results of cassette-based COVID-19 home tests are typically displayed in a ‘raw’ format that may be misinterpreted by lay users (e.g., ‘C’ indicating control could be misunderstood as ‘C’ indicating COVID-19).
• When cassette labeling appears in multiple orientations, the user must rotate the cassette to read labeling.
• A transparent shield over the results window can create optical challenges.

Recommendation

• Optimize chemistry in LFAs to maximize control and test line contrast and sharpness.
• Result labeling should comply with recommendations in 8.1 Legibility.
• Ensure cassette labeling aligns exactly with the position of the control and test lines in the results window.
• Abbreviations should be adequately defined in the test instructions (see also 9.5 Cassette for additional labeling suggestions).
• When feasible, design the results status to be self-communicative and interpreted without the need for a key/legend (e.g., spell out ‘Control’ and ‘Test’ on cassette.
• Cassette labeling should all be in the same orientation.
• If cassette design includes a transparent shield over the results window, carefully consider how optics (e.g., refraction or reflection) might interfere with results interpretation.

Issue

Most tests only communicate results visually.

Recommendation

Consider adding nonvisual cues such as audible and/or haptic feedback to communicate results.

11. References