Interpretation! The difference between calibrators, standards and controls

First, the difference in definition

1. Calibrator: The calibration for the test item used for quantitative detection is a reference material with the value of the independent variable used in the calibration function. It usually contains 2 to more concentration levels.

2, quality control: used to check the performance of analytical instruments or methods, is a stable substance used to verify the performance of analytical instruments or methods.

3. Standard: A substance having a determined characteristic value for evaluating the measurement method. Including national reference products and internal reference materials, it can be used for quality control of main raw materials, production process and determination of reaction system, product release, registration inspection, supervision and inspection.

Second, do you need to register?

1. Calibrator: Generally, it can be combined with the matching reagent to apply for registration, or it can be applied for registration separately;

2, quality control products: generally can be combined with the diagnostic reagents to apply for registration, you can also apply for registration separately.

3. Standard products: The national reference products are organized and calibrated by the China Food and Drug Administration Institute and submitted to the National Drug Standards Committee for approval. The internal standard products of the enterprise are developed by the enterprise according to the characteristics of the product to meet the quality control and performance evaluation in the production process of the product, and generally do not need to be registered.

Third, do you need traceability documents?

1. Calibrator: A complete traceability document is required.

2, quality control products: generally no traceability requirements, but for fixed value control products, there are requirements for assignment accuracy.

3. Standard products: If there are corresponding national or international standard products, the internal standard products of the enterprise should be traced to national or international standards; if there is no national or international standard, the preparation of enterprise reference products should have standardized quality. The control program, for example, is verified by the gold standard method or the similar products already listed.

Fourth, performance evaluation indicators

1. For calibrators and quality control products, in addition to traceability differences, generally include requirements for loading, bottle-to-bottle, biosafety, and stability.

2. For standard products: According to the different items, use the corresponding kit or gold standard method to verify and analyze the reference products.


The calibrators, standards, and quality control products are all reference materials. A reference substance is a material or substance, and one or more of the characteristic values ​​are only uniform and well defined, used to calibrate the measurement system, evaluate the measurement procedure, or assign values ​​to the material. But the three do not use a concept, they have different applications. There are often many erroneous applications in clinical practice, such as applying calibrators from different manufacturers to the detection system; using a quality control product to evaluate the detection system; using quality control products to calibrate the detection system, and so on. The source of the calibrators, standards, and controls, and the method of setting the values, lead to the correct use of the three reference materials.

1. The shortcomings of the traditional method

Traditional inspection items, in order to make the test results reliable or valid, are often measured together with the sample using a standard of known concentration.

The traditional standard solution is prepared with pure water. Compared with serum, the composition is very simple, except for the substance to be tested. At this time, a matrix effect is introduced when the sample is compared with the standard.
Matrix effect: The effect of non-assay substances in the sample on the measured amount.

In other words, in other words, the interference of other substances outside the object in the sample against the || detection causes the detection result to deviate from the true value.
At this point, the sample value of the sample with matrix effect obtained by comparison with the standard without matrix effect will deviate from the true value.

The standard solution can be used directly depending on the method of detection, the decisive method of minimizing interference, or the reference method of some known interference.

2, the standard value of the standard
In general, the standards used in the inspection work are application standards. The pure product meeting the quality standard is formulated into a solution using a weighing method and a volumetric method. The measurement was repeated by a decisive method, and the results were within the prescribed range. The reliability of the assay depends on the method of identification, which is less reliable than the accepted weighing method and volumetric method. The standard value is determined by the weighing and volume method. Never substitute the measured value for the correction.

3. Introducing calibrators
To overcome the matrix differences between pure standards and patient samples, calibrators with similar matrix effects to patient samples were used 20 years ago to replace the standard for routine work.

4, the value of the calibrator
1. Source of calibrators: Most of the calibrators are from a mixture of human samples, such as mixed serum. The analyte itself is contained in the analyte, and the vegetation is added with certain analytes at the moment to increase the content.
2. Fixed value method: The content of the analyte in the calibrator cannot be determined by the weighing method and the volume method, and can only depend on the analytical method. The calibration value of the calibrator can only be determined by the analytical method and the detection system. However, all test methods, instruments, reagents, etc. used in the test are used to monitor the patient's fresh sample, not to monitor the sample processed by the calibrator. All calibrators are processed samples with new matrix differences from fresh samples. If a well-established reference method is used to standardize the calibrator, the assay procedure is rigorous and the assay is only reliable, but not a calibration value. When using this measurement to calibrate a conventional detection system, the analyte in the calibrator is significantly different from the fresh patient sample when tested, and the accuracy of the reference method series cannot be passed to the patient via the calibrator.
If a patient sample is first tested using a recognized reference method, then a patient sample with a reference value is used to calibrate a test system. At this point, when the detection system detects other fresh patient samples, the traceability of the results of these patient samples can be traced back to the accepted reference method. Also using fresh patient samples is the best calibrator for the calibration system.
However, fresh patient samples with reference values ​​cannot be used for routine calibration of all methods, instruments, reagents, or detection systems; relying on existing calibrators, it is critical to determine the calibration values ​​for the calibrators. The only requirement for the reliability of the calibration calibration value is that the calibration system after calibration of the calibration product is comparable to the test results of the patient sample test and the test results of certain specified reference methods.
The calibration value is not the measured value and is the corrected adjustment value.

5, the specificity of the calibrator
In the past applications, users often do not pay attention to the specificity of the application of the calibrator. Any method or instrument or reagent uses a calibrator, which seriously affects the quality of the inspection. From the above calibrator method, we can know that only when using the same detection system as the fixed value, the results can be compared with the reference method results.

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6, quality control products fixed value
1. Source of quality control products: The source of quality control products is almost the same as that of calibrated products. Manufacturers may add a lot of substances to their own requirements. At this time, the added amount of some substances often reaches the high concentration of pathological conditions. For a project, the matrix effect will be greater for this project.
2. Fixed value method: Some manufacturers will set a fixed value range for their own standard. This fixed value range is determined by the manufacturer and several clinical users who use the same detection system. At this time, if the control is applied to another detection system, due to the difference in methodology, a value that is significantly different from the value given by the manufacturer may be obtained. At this time, the accuracy of the detection system cannot be considered to be poor. At this point it is important to emphasize that the detection system is used to measure fresh serum, not to measure quality control or other substances. The detection system is traceable only if it is the result of detecting fresh serum. Different detection systems are only comparable when detecting fresh serum.