2. Westgard rules
12s rule: the run is accepted when both control results are within 2 SD limits from the mean value
13s rule: the run is considered out of control when one of the control results exceeds the ±3 SD limits
22s rule: the run is rejected when both controls exceeds the mean value +2 SD or the mean -2 SD ; dispersion

3. R4s rule: The run is rejected when both controls exceeds the mean +2 SD limit and one exceeds the mean -2 SD limit or when the range of a group of controls exceeds 4SD ; dispersion
41s rule: The run is rejected when four consecutive control results exceeds the mean +1 SD or the mean -1 SD ; trend
10x rule: The run is rejected when the last 10 consecutive control results fall on the same side of the mean ; trend