Please note: The QC Selection Grid display is not functional at this time.

Directions

Use the table below to calculate your Critical-Error (Δ SEcrit). You need to know your analytical quality requirement (i.e. a CLIA requirement for total analytical error at a given medical decision level), your method bias (for that decision level), and your method cv (for that decision level). For more thorough instruction, view the Lesson on QC Selection Grids.
Click here to see examples you can plug in.

Enter your test's Quality Requirement (TEa) as a percentage: 
[Hint: look up the CLIA requirement for your analyte] 
Enter your Method CV (smeas) as a percentage: 
Enter your Method Bias (biasmeas) as a percentage: 
Click here to see what your critical-error is:
Your critical-error will appear below when you click the button:
 
To use the QC Selection Grid, you will need to know your critical-error as well as your frequency of errors for your instrument. Once those are entered you can click "multirule" for a multirule recommendation and/or "single rule" for a single control rule recommendation. In both cases, another window will appear showing the recommendation. You can switch between windows to compare the multirule and single rule recommendations. If you decide to enter new data, close the recommendation windows first.
Enter the Critical Systematic Error:
(You can calculate that above if it isn't already entered)

Next, categorize the stability of your method:

 Excellent; problems with less than 2 runs per 100 
Moderate; problems with 2 to 10 runs per 100 
Poor: problems with more than 10 runs per 100

 

 

For more quantitative answers, use the Normalized OPSpecs calculator or use EZ Rules 3 QC Design software.
 

Examples:

 

1. Hemoglobin at a decision level of 9 g/dL:

0.117 g/dL method CV = 1.3% method CV (imprecision)
0.0 g/dL method bias = 0.0% method bias (inaccuracy)
CLIA PT requirement of 7% (See our CLIA page to see more hematology requirements)
What multirule would be recommended for a system with excellent stability? moderate stability? poor stability?

2. Cortisol at a decision level of 50 ug/dL:

2.65 ug/dL method CV = 5.3% method CV (imprecision)
0.0 ug/dL method bias = 0.0% method bias (inaccuracy)
CLIA PT requirement of 25% (See our CLIA page to see more endocrinology requirements)
What single control rule would be recommended for a system with excellent stability? moderate stability? poor stability?

3. Theophylline at a decision level of 10 ug/dL:

0.64 ug/dL method CV = 6.4% method CV (imprecision)
1.0 ug/dL method bias = 10% method bias (inaccuracy)
CLIA PT requirement of 25%  (See our CLIA page to see more toxicology requirements)
In this worst-case scenario, assume that your instrument had poor stability, would it be easier for you to implement a multirule or a single control rule?