For those consumers who would like to maintain their own equipment, we offer test kits and instructions to facilitate this process. You can test the calibration of your aneroid or mercurial manometer by connecting it to a unit of known accuracy. Testing is typically performed by taking simultaneous readings to eliminate timing variances, and it is highly recommended that you use the most precise reference instrument available to conduct this type of testing. (Typically this would be a precise digital device or mercurial unit. An aneroid manometer is never appropriate for this type of testing).
It is important to note that the level of accuracy you will attain is directly related to the accuracy of the device that you are using to perform your testing. For example, if you are using a known reference standard that is accurate to +/- 1 mmHg, you will never achieve an accuracy greater than +/- 4 mmHg since your reference device may vary by +/- 1 mmHg and the device you are testing is allowed to vary by as much as +/- 3 mmHg. Selecting the proper reference device is critical to accurate test results, and we recommend using a device that is accurate to +/- 0.1 where possible to obtain the best results.
To conduct the testing, connect your equipment to the reference instrument of known accuracy using a ‘Y’ test kit. This will allow you to simultaneously inflate both devices and monitor the readings. We offer a test kit (part number 991) that can facilitate this type of testing. Our test kit is equipped with a number of different connectors and is ideal for a variety of sphygmomanometer configurations.
First inflate both instruments to 300 mmHg to begin the test. Then slowly deflate both devices at a rate of 2-3 mmHg, pausing at the following five points and checking the reading on both instruments:
240 to 250 mmHg
190 to 200 mmHg
140 to 150 mmHg
90 to 100 mmHg
40 to 50 mmHg
The instrument you are testing must be within +/-3 mmHg of your reference device at all points during this calibration check. If you find that the unit differs from the reference device by more than +/- 3 mmHg at any test point, repeat the test once to verify that there is an inaccuracy. It is important to note that you must subtract the tolerance of your reference standard from the measurement when determining accuracy. If your reference standard is only accurate to +/- 1 mmHg, then your test device must be within +/- 2 mmHg of the reading. If you can confirm that the instrument is not reading within +/- 3 mmHg of the reference device, you should return your instrument to ADC for recalibration and/or warranty servicing.
Qualified institutions may request a copy of our complimentary field re-calibration guide. Click here to request this guide.