Patient Misidentifications Caused by Errors in Standard Bar Code Technology Marion L. Snyder, 1,2 Alexis Carter, 1 Karen Jenkins, 3 and Corinne R. Fantz 1* BACKGROUND: Bar code technology has decreased tran- scription errors in many healthcare applications. How- ever, we have found that linear bar code identification methods are not failsafe. In this study, we sought to identify the sources of bar code decoding errors that generated incorrect patient identifiers when bar codes were scanned for point-of-care glucose testing and to develop solutions to prevent their occurrence. METHODS: We identified misread wristband bar codes, removed them from service, and rescanned them by using 5 different scanner models. Bar codes were re- printed in pristine condition for use as controls. We determined error rates for each bar code–scanner pair and manually calculated internal bar code data integ- rity checks. RESULTS: As many as 3 incorrect patient identifiers were generated from a single bar code. Minor bar code im- perfections, failure to control for bar code scanner res- olution requirements, and less than optimal printed bar code orientation were confirmed as sources of these errors. Of the scanner models tested, the Roche ACCU- CHEK® glucometer had the highest error rate. The in- ternal data integrity check system did not detect these errors. CONCLUSIONS: Bar code–related patient misidentifica- tions can occur. In the worst case, misidentified patient results could have been transmitted to the incorrect patient medical record. This report has profound im- plications not only for point-of-care testing but also for bar coded medication administration, transfusion recipient certification systems, and other areas where patient misidentifications can be life-threatening. Care- ful control of bar code scanning and printing equip- ment specifications will minimize this threat to patient safety. Ultimately, healthcare device manufacturers should adopt more robust and higher fidelity alterna- tives to linear bar code symbologies. © 2010 American Association for Clinical Chemistry Bar code technology has been an indispensable ad- vancement for patient safety. When used for patient and/or specimen identification, bar codes, combined with the appropriate software, permit clinical staff to instantly identify individual patients and their medica- tions and specimens and have significantly reduced identification and data entry error rates (1, 2 ). Despite this, there still exists the potential for bar code misreads and patient misidentification. On the basis of findings in our institution, we estimate that more than 1 in 84 000 bar code–scanning events generate an incorrect patient identifier. We were first alerted to bar code–related errors in our institution when several patients’ point-of-care testing (POCT) 4 glucose results were not transmitted to the intended patient medical records. Iterative scan- ning of wristbands from these patients produced both correct and incorrect patient identifiers. The defective bar codes originated from 2 different printer models (Datacard Model LBD24-2043-002 and FastMark AMT Datasouth Model 4602), with each printer model printing a specific sized bar code (width by height = 13  13 mm or 25  12 mm, respectively, where bar code width was defined as the measured distance across the bar code, perpendicular to the long axis of the bar code bars). Visual examination of the problematic wristbands revealed fine white lines in the black alpha- numeric text juxtaposed to the bar code. These lines were parallel to and ran through the adjacent bar code bars, splitting a single bar code bar into 2 bars of vari- able width. These white lines were observed in all faulty wristbands. Printers responsible for generating these faulty bar codes were either replaced or removed from service for maintenance. 1 Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA; 2 Department of Pathology, Brigham and Women’s Hospital, Boston, MA (current address); 3 Emory University Hospital Midtown, Emory Medical Labo- ratories, Atlanta, GA. * Address correspondence to this author at: Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 1364 Clifton Road, NE, Atlanta, GA 30322. Fax 404-712-5596; e-mail cfantz@emory.edu. Received May 18, 2010; accepted July 16, 2010. Previously published online at DOI: 10.1373/clinchem.2010.150094 4 Nonstandard abbreviations: POCT, point-of-care testing; CkChr, check charac- ter; RACG, Roche ACCU-CHEK glucometer; CCD/LED, charge-coupled device/ light-emitting diode; CkSum, check sum. Clinical Chemistry 56:10 1554–1560 (2010) Informatics and Statistics 1554