Autonomous swab robot for naso- and oropharyngeal COVID-19 screening

The COVID-19 outbreak has triggered a global health and economic crisis, necessitating widespread testing to control viral spread amidst rising cases and fatalities. The recommended testing method, a combined naso- and oropharyngeal swab, poses risks and demands limited protective gear. In response to the COVID-19 pandemic, we developed and tested the first autonomous swab robot station for Naso- and Oropharyngeal Coronavirus Screening (SR-NOCS). A force-sensitive robot running under a Cartesian impedance controller is employed to drive the swab to the sampling area. This groundbreaking device underwent two clinical studies-one conducted during the initial pandemic lockdown in Europe (early 2021) and the other, more recently, in a public place after the pandemic had subsided earlier in the year 2023. In total, 52 patients suspected of COVID-19 infection were included in these clinical studies. The results revealed a complete positive correlation between autonomous and manual sampling. The test subjects exhibited a high acceptance rate, all expressing a willingness to undergo future tests with SR-NOCS. Based on our findings, such systems could enhance testing capabilities, potentially conducting up to 300 tests per robot per day with consistent precision. The tests can be carried out with minimal supervision, reducing infection risks and effectively safeguarding patients and healthcare workers.


S4 Safety & hygienic measures
The two identified main risks of this kind of study are the physical interaction with the robot and the risk of cross-infection.Therefore, several precautionary measures were implemented for this prototypic setup.A plexiglass wall was placed to restrict the robot's motions mechanically.Direct physical interaction with the test subjects was only possible via a flexible swab through the fixture hole in a restricted motion range.The test subjects controlled the robot's start (with confirmation from the operator) and could always freely move away from the plexiglass wall.The interaction with the trained hospital employees only occurred if the robot was stopped.To prevent cross-infection, the employees changed gloves, and mouth-and-nose disposable fixtures and fully disinfected the station, robot, and chair surfaces using Perform © fabrics (Schülke & Mayr GmbH, Norderstedt, Germany) between tests.Additionally, the robot's cover and finger gloves were changed every few tests or if a test subject coughed.The tests were performed in a well-ventilated open garage with the employees and test subjects maintaining a safe distance between themselves.

S5 Data availability statement
The study has been registered to the German Registry of Clinical Studies (DRKS) with the ID DRKS00021420 (www.drks.de).The study is also approved by the WHO Registry (http://apps.who.int/trialsearch/).The datasets generated and/or analyzed during the current study will be available via these repositories.

S6 Summary of the State of the Arts contributions
Table S1 summarizes key attributes from state-of-the-art papers referenced and discussed in our manuscript.Each paper is assigned a unique reference number, and the 'System Characteristics' column provides a concise overview of the essential features, design, and control mechanisms of the discussed robotic systems.Categorization in the 'Type of Study' column offers insights into methodologies, encompassing various study types.'Clinical Study' indicates direct engagement with patients or volunteers.'In Hospital' and 'In Public' describe testing environments, while 'Autonomous' and 'Teleop' signify system automation levels.'Number of Participants' quantifies the study scale, 'Force Measurement' highlights sensitivity, and 'TRL' (Technology Readiness Level: further information can be found on this link: https://www.twi-global.com/locations/deutschland/was-wir-tun/haeufig-gestellte-fragen/was-sind-technology-readiness-levels-trls) reflects the developmental maturity of the systems.This detailed table enhances accessibility, providing a valuable resource for readers to navigate and understand the nuances of each study.Further abbreviation on the table: 'NF' refers to Data Not Found in the cited paper.

S7 Trial Timeline
Figure S1 illustrates the flow of the automated tests being studied (current iterations, evaluated in this study).In the clinical study, the initial step (registration) is manually performed by the scientific staff due to the limited number of subjects (a detailed description of the subject information sheet is provided).Before a subject enters the test station, the station is prepared and cleaned by the scientific staff.This process includes removing the nose and mouth adapter, immersing it in disinfectant liquid following the manufacturer's instructions, and conducting a thorough surface disinfection of the Plexiglas disc, chair, robot, and gripper.The sterile nose and mouth adapter is then reinserted before releasing it for the next test.The test station comprises two adjacent cubicles physically separated by a wall.Typically, two subjects are accommodated per test run, and their scheduling is coordinated to avoid overcrowding in the waiting area.Subjects are called into the study room one at a time, with subject 2 entering once subject 1 is seated.After the test run, subjects exit the study room sequentially to prevent direct contact between patients at a microscopic level.Macrologistics and waiting room administration are not within the scope of this study.However, we will analyze the impact of parallelization and micrologistic measures on waiting times to optimize patient organization during clinical deployments.The main steps are outlined and demonstrated in Figure S1.These steps correspond to those performed at the existing prototypical station.Here below we detail those nine steps depicted in Figure S1.

S7.1 Registration and test kit handover
Easy-to-understand instructions about the study procedure, including manual registration and contactless handover of the test kit.

S7.2 Open test kit
Before opening the test kit, the individual must wash and disinfect their hands.The process of opening the kit is demonstrated in advance, and each component is explained.The kit includes disposable gloves, a mouthpiece, a nosepiece, a mask, and disinfection materials.

S7.3 Post-disinfection by test subjects
After the technical staff demonstrates the disinfection process, the test subject is responsible for disinfecting their station.They should use the disinfection materials provided in the test kit, along with the gloves and mask.

S7.4 Inserting the nose disposable fixation
The test subject is trained to insert the disposable nose fixation while wearing gloves.

S7.5 Inserting the mouth/throat disposable fixation
the test subject is trained to insert the disposable mouth/throat fixation while wearing gloves.

S7.6 Nasal swab left
The test is initiated following instructions from qualified personnel.Each examination step and robot movement can only be initiated by pressing the foot pedal.Once the robot reaches the test starting position, the subject should place their nose on the nose cap and begin the test by pressing the foot pedal.The subject can interrupt the test at any time by pressing an emergency stop button to halt the robot.Additionally, the test subject has the option to make unlimited evasive movements to the rear at any time.

S7.8 Throat swab
The test is initiated following instructions from qualified personnel.Each examination step and robot movement can only be initiated by pressing the foot pedal.Once the robot reaches the test starting position, the subject should place their throat on the mouth/throat fixation and begin the test by pressing the foot pedal.The subject can interrupt the test at any time by pressing an emergency stop button to halt the robot.Additionally, the test subject has the option to make unlimited evasive movements to the rear at any time.

S7.9 Cleaning and fixations removal by test subjects
After a successful test procedure, the test subject should remove the disposable mouth and nose fixations, pre-disinfect their station, and dispose of all used materials.Subsequently, qualified personnel will clean and disinfect the test station.The station operator ensures the complete removal of the nose and mouth fixations, immerses them in disinfectant liquid following the manufacturer's instructions, and conducts a thorough surface disinfection of both sides of the Plexiglas disc, the chair, the robot, and the gripper.Swabs are collected and sent to the laboratory.Finally, the sterile nose and mouth adapter is replaced and prepared for the next test.

S8 Data Availability
Correspondence and requests for materials should be addressed to Sami Haddadin (haddadin@tum.de).
Figure S1: Steps within single trial timeline.

Table S1 :
Table summarizing the current advancements in swabbing systems for comparative analysis with our work.