Levey Jennings chart If a control point falls outside the +/- 2SD of the mean value, the control results are considered to be "out of control" and patient samples cannot be run or reported. NOTE: ONE control point out of 20 outside of +/- 2 SD is acceptable (95% confidence limits) If the control values falls within the +/- 2SD of the mean value, the QC results are "in control" and patient results may be reported