What is a trend in QC?
A trend is a continuous movement of values in one direction over six or more analytical runs. Trends can start on one side of the mean and move across it or can occur entirely on one side of the mean. Trends can be caused by deterioration of reagents, tubing, or light sources.
What is a trend in Six Sigma?
Applicable to run charts and control charts, a shift in its most basic form is seven points in a row either above or below the centerline. A trend is seven points in a row in an upward direction or seven points in a row in a downward direction. With a trend, it doesn’t matter if the centerline is crossed.
What is internal and external quality control?
Internal and external quality control programs complement each other. Internal quality control monitors the daily precision and accuracy of methodologies, personnel, and instruments. External quality control maintains long term accuracy. Increased confidence in the accuracy of the laboratory’s testing results.