Recommended Steps

When setting up a QC system, it is important to make sure you choose statistical process control (SPC) rules to maximize error detection while minimizing false rejections.

Clinical and Laboratory Standards Institute (CLSI–C24-A3, section 6) recommends using the following steps when setting up a QC system:

1. Determine the quality requirements for the test.
2. Identify appropriate control materials to use.
3. Evaluate test performance.
4. Identify possible QC procedures.
5. Predict the performance of the identified QC procedures.
6. Choose goals based on the required quality.
7. Select a QC procedure.

Obviously, this is not a simple process which may explain why many laboratories fall back on the 1_2s rule. Although the 1_2s rule produces too many false alarms, it feels safe.

Tip: The optional Westgard Advisor™ online makes the complex task of choosing the appropriate SPC rules easier. See "Westgard Advisor™ online" for more information.