Questions about Independent Quality Controls

What is an independent control?

The term “independent" control is used to describe a control material that:

  • Provides an unbiased, independent performance assessment for an analytical process
  • Is not optimized to work with any specific test system
  • Is manufactured independently of instrument, calibrators and reagents

Why should I use an independent control?

Many instrument manufacturers provide both calibrators and control materials for use specifically with their own systems. These controls are often designed and manufactured from the same materials as the calibrators. Consequently, the control may mimic the calibrator, making it less sensitive to changes in device performance. This can lead to acceptance of patient test results with analytical error that could be medically important.

What are some other benefits of using independent controls?

Often times, a laboratory using an instrument manufacturer or in-kit control may receive a different control lot with each new reagent lot. This does not provide the laboratory with the benefits of long-term QC monitoring. Independent controls with a longer shelf life allow use of the same control lot over multiple batches of reagents and calibrators, giving the laboratory the ability to detect shifts that may occur with new lot of reagents or calibrators.

A control with a long shelf life allows for long-term QC monitoring across different reagent lots and saves time and money due to fewer lot crossovers. See chart to help provide further explanation.

Crossover

Are there any specific guidelines or recommendations regarding the use of independent controls?

Yes. There are several professional organizations that specifically recommend using independent controls. See examples ▸

What is the difference between a calibrator and a control?

Calibrators and controls are not the same. They are designed to be used for two completely different purposes.

A calibrator is a material or in vitro medical device with known quantitative / qualitative characteristics (concentration, activity, intensity, reactivity) that is used to calibrate, graduate, or adjust a measurement procedure.

A control is used to monitor an analysis performance within desired limits.

Should a calibrator also be used as a control?

No. If a calibrator is also used as a control, then the control will closely mimic the calibrator. In this situation, the control may not be able to detect shifts in values that could be caused by a degrading calibrator. Read more from Clinical and Laboratory Standards Institute ▸

Can I use Bio-Rad controls with Bio-Rad instruments and methods?

Yes. Bio-Rad is the worldwide leader in quality controls for the clinical laboratory. Bio-Rad also provides a wide range of instruments and assay methods. Bio-Rad quality controls meet all the criteria for an independent control. The controls are manufactured independently of the calibrators and reagents, and are not optimized to work with any specific instrument or method. Bio-Rad controls provide an unbiased, independent assessment of performance, regardless of the instrument or reagent manufacturer.