Related Experiment Video
Updated: Aug 7, 2026
Fabrication and Characterization of a Conformal Skin-like Electronic System for Quantitative, Cutaneous Wound Management
Published on: September 2, 2015
Initial clinical evaluation of a handheld device for detecting retained surgical gauze sponges using radiofrequency
Alex Macario1, Dean Morris, Sharon Morris
1Department of Anesthesia and Health Research and Policy, Stanford University School of Medicine, Stanford, CA 94305-5640, USA. amaca@stanford.edu
Hypothesis:
A handheld wand-scanning device (1.5 lb, battery powered, 10 x 10 x 1.5 in) has been developed to detect commonly used surgical gauze sponges, which have been tagged with a radiofrequency identification (RFID) chip. We tested the hypothesis that this wand device has a successful detection rate of 100%, with 100% specificity and 100% sensitivity.
Design:
Prospective, blinded, experimental clinical trial.
Setting:
Stanford University Medical Center, Stanford, Calif.
Patients:
Eight patients undergoing abdominal or pelvic surgery.
Interventions:
Eight untagged sponges (1 control per patient) and 28 RFID sponges were placed in the patients. Just before closure, the first surgeon placed 1 RFID sponge (adult laparotomy tape; 18 x 18 in, 4-ply) in the surgical site, while the second surgeon looked away so as to be blinded to sponge placement. The edges of the wound were pulled together so that the inside of the cavity was not exposed during the detection experiments. The second (blinded) surgeon used the wand-scanning device to try to detect the RFID sponge.
Main Outcome Measures:
A successful detection was defined as detection of an RFID sponge within 1 minute. We also administered a questionnaire to the surgeon and nurse involved in the detections to assess ease of use.
Results:
The RFID wand device detected all sponges correctly, in less than 3 seconds on average. There were no false-positive or false-negative results.
Conclusions:
We found a detection accuracy of 100% for the RFID wand device. Despite this engineering success, the possibility of human error and retained sponges remains because handheld scanning can be performed incorrectly.
