The measurement and monitoring of blood pressure by means of catheters and strain gauges may have errors due to unstandardized transducers and amplifiers. Inaccuracies in measurement were found to be over 10% in a large hospital. Causes for these errors were analyzed, and methods for reducing errors are presented. It is shown that to maintain accuracy, strain guages must have equal and exactly known sensitivity factors and that amplifiers have to exhibit constant gain and offset. The design of a simple and accurate strain gauge simulator with a precision of better than 0.3% is presented, and formulae for component selection and error analysis are developed. It is concluded that an appropriate quality control program for pressure-measuring equipment will uncover problem areas and ensure accurate pressure measurements.