Proceedings Article | 31 December 2010
KEYWORDS: Sensors, Calibration, Blood, Glucose, Measurement devices, Blood pressure, Oxygen, In vivo imaging, Tissues, Standards development
Invasive and non-invasive measurement sensors and systems perform vital roles in medical care. Devices are based on
various principles, including optics, photonics, and plasmonics, electro-analysis, magnetics, acoustics, bio-recognition,
etc. Sensors are used for the direct insertion into the human body, for example to be in contact with blood, which
constitutes Invasive Measurement. This approach is very challenging technically, as sensor performance (sensitivity,
response time, linearity) can deteriorate due to interactions between the sensor materials and the biological environment,
such as blood or interstitial fluid. Invasive techniques may also be potentially hazardous. Alternatively, sensors or
devices may be positioned external to the body surface, for example to analyse respired breath, thereby allowing safer
Non-Invasive Measurement. However, such methods, which are inherently less direct, often requiring more complex
calibration algorithms, perhaps using chemometric principles. This paper considers and reviews the issue of calibration
in both invasive and non-invasive biomedical measurement systems. Systems in current use usually rely upon periodic
calibration checks being performed by clinical staff against a variety of laboratory instruments and QC samples. These
procedures require careful planning and overall management if reliable data are to be assured.
