Many instrument manufacturers provide both calibrators and control materials for their own systems. These controls are designed for use only on their own test systems, but more importantly, they are often manufactured from the same materials as the calibrators.
Consequently, the control may mimic the calibrator, making it less sensitive to changes in device performance. This can lead to acceptance of patient test results with analytical error that could be medically important.
Conversely, independent quality controls which are more like patient samples, may be better able to detect performance shifts. This can increase confidence in reported patient results.