Sphygmomanometers register blood pressure using a mercury column.
Parts of a Sphygmomanometer:
For accurate Measurement, it is not necessary for the gauge needle to rest at zero point but please make sure that the gauge needle should rest within the area of zero square prior to use. The zero square itself reflects the warranty for accuracy, i.e. ± 3 mmHg.
Yes, sphygmomanometer unit should be calibrated regularly for at least once a year.
The wrong cuff size will lead to inaccurate blood pressure measurement since the initial pressure given for the measurement may vary depends on how large the arm circumference is. When the cuff size is right the white index line comes in the range between the arrows after the cuff has been put on.
Ask here and we’ll get right back to you!