• Selecting a wrong size of cuff results in an inaccurate reading. A narrow cuff wrapped round a fat arm will give an abnormally high reading, and vice versa
• The accuracy of an aneroid sphygmomanometer declines with use, due to physical defects in the casing and tubing or the indicator needle drifting to zero
• Although the von Recklinghausen oscillotonometer is accurate for mean arterial pressure, it does not accurately measure diastolic pressure
• NIBP is inaccurate at extremes of blood pressure. Non-invasive devices tend to over-read at low blood pressure, and under-read at very high blood pressure
• The arm should be at the level of heart whilst taking the reading
• As blood pressure measurement relies on regular pulse, arrhythmias such as atrial fibrillation can cause inaccurate readings
• Movement of the arm, shivering or external pressure, such as someone leaning on the arm, can cause an inaccurate reading
• The pressure effects of frequent cuff inflation for a prolonged period can cause nerve damage and petechial haemorrhages