Sensitivity of commercial scanners to microchips of various frequencies implanted in dogs and cats

Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA.
Journal of the American Veterinary Medical Association (Impact Factor: 1.56). 01/2009; 233(11):1729-35. DOI: 10.2460/javma.233.11.1729
Source: PubMed


To evaluate the sensitivity of 4 commercially available microchip scanners used to detect or read encrypted and unencrypted 125-, 128-, and 134.2-kHz microchips under field conditions following implantation in dogs and cats at 6 animal shelters.
Cross-sectional study. Animals-3,949 dogs and cats at 6 animal shelters.
Each shelter was asked to enroll 657 to 660 animals and to implant microchips in 438 to 440 animals (each shelter used a different microchip brand). Animals were then scanned with 3 or 4 commercial scanners to determine whether microchips could be detected. Scanner sensitivity was calculated as the percentage of animals with a microchip in which the microchip was detected.
None of the scanners examined had 100% sensitivity for any of the microchip brands. In addition, there were clear differences among scanners in regard to sensitivity. The 3 universal scanners capable of reading or detecting 128- and 134.2-kHz microchips all had sensitivities > or = 94.8% for microchips of these frequencies. Three of the 4 scanners had sensitivities > or = 88.2% for 125-kHz microchips, but sensitivity of one of the universal scanners for microchips of this frequency was lower (66.4% to 75.0%).
Results indicated that some currently available universal scanners have high sensitivity to microchips of the frequencies commonly used in the United States, although none of the scanners had 100% sensitivity. To maximize microchip detection, proper scanning technique should be used and animals should be scanned more than once. Microchipping should remain a component of a more comprehensive pet identification program.

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    ABSTRACT: To evaluate sensitivity of 4 commercially available microchip scanners used to detect or read encrypted and unencrypted 125-, 128-, and 134.2-kHz microchips under controlled conditions. Evaluation study. Microchip scanners from 4 manufacturers and 6 brands of microchips (10 microchips/brand). Each microchip was scanned 72 times with each scanner passed parallel to the long axis of the microchip and 72 times with each scanner passed perpendicular to the long axis of the microchip. For each scan, up to 3 passes were allowed for the scanner to read or detect the microchip. Microchip and scanner order were randomized. Sensitivity was calculated as the mean percentage of the 72 scans for each microchip that were successful (ie, the microchip was detected or read). Results-None of the scanners had 100% sensitivity for all microchips and both scanning orientations, and there were clear differences between scanners on the basis of operating frequency of the microchip, orientation of the microchip, and number of passes used to detect or read the microchip. For the 3 scanners designed to detect or read microchips of all 3 frequencies currently used in the United States, sensitivity was highest for 134.2-kHz microchips and lower for 125- and 128-kHz microchips. None of the scanners performed as well when only a single pass of the scanner was used to detect or read the microchips. Results indicated that use of multiple passes in different directions was important for maximizing sensitivity of microchip scanners.
    Journal of the American Veterinary Medical Association 01/2009; 233(11):1723-8. DOI:10.2460/javma.233.11.1723 · 1.56 Impact Factor
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