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About this tool
Calculate mean, SD, CV and laboratory control limits.
Sample standard deviation is used (n−1). Interpret QC results according to your laboratory's validated procedures and control material requirements.
Interpreting laboratory quality-control statistics
The tool calculates arithmetic mean, sample standard deviation, coefficient of variation and illustrative ±2 SD and ±3 SD limits.
Worked example
For control values 100, 102, 99, 101 and 98, the mean is 100 and sample SD is about 1.58.
Frequently asked question
Does this establish a valid laboratory control range?
No. Validated control limits require appropriate historical data, methods and laboratory quality procedures.