General principles for laboratory verification of analytical systems

General principles for laboratory verification of analytical systems

Laboratory verification analysis system, should comply with the following general principles:

a) The established analytical system shall be verified using the specified analytical system verification tools. If the verification shows that the system is running beyond the control range, the test results are not credible, and the causes need to be investigated, and the analysis system needs to be re-tested after corrective measures are implemented. Laboratory managers also need to develop procedures for feedback on the verification of analytical systems, corrective actions, and incentives for employees. Due to the influence of errors, it may be impossible to identify the error or short-term interference in the test of individual samples.

B) The laboratory shall specify the departments or personnel responsible for the verification of the analysis system.

c) The conclusions obtained through the verification results of the analysis system are only suitable for the detection of samples within the concentration range after the verification or confirmation of the detection method.

d) For the analysis system established through method verification or confirmation, the elements of the system are determined, and the performance indicators of the system prove that it can meet the relevant requirements and can produce accurate and reliable test results. Once the elements change, it is necessary to reconfirm the degree of influence of the changed elements on the test results, and adjust the analysis system according to the confirmed results.

e) The main quality responsibility of the inspection personnel in the inspection process is to ensure the stability of the analysis system, and implement the quality control measures of the inspection process in strict accordance with the requirements of SOP. When the results meet the requirements of SOP, the inspection results can be reported.

f) The quality control department or quality control personnel of the laboratory shall carry out the verification of the analysis system according to the requirements of SOP, and draw a conclusion on whether the system is normal or not according to the verification results. If the verification shows that the system has deviated, the quality control department or quality control personnel work with the inspection personnel to analyze the cause and formulate and implement corrective measures. After the implementation of corrective measures, the quality control department or quality control personnel should check the analysis system again to prove that the system has returned to normal.

Quality control samples for verification of analytical systems

1. The nature of quality control samples

The quality control samples used for analysis system verification shall have the characteristics of stable nature, constant content, sufficient uniformity and sufficient quantity. The laboratory shall ensure that these four requirements are met.

2. Quality control sample type

The quality control samples used for analysis system verification include certified standard samples, I .e. CRM matrix, standard solution, reference substance or internal quality control substance, blank sample and regular test sample:

a)CRM matrix, the laboratory uses the repeated test results of CRM matrix to accurately reveal the system effect (bias) and precision. Whenever practical and economic conditions permit, the CRM matrix should be used as much as possible. However, compared with the sample, CRM matrix has better uniformity and less interference substances, and the precision of repeated detection results using CRM matrix is often better than that of repeated detection using regular samples, which should be paid attention to by laboratories.

B) The standard solution, reference substance or internal quality control substance is the same as the CRM matrix. The standard solution, reference substance or internal quality control substance can also provide system effect and random effect information related to the method. If it has been demonstrated at the initial stage of method validation or validation that laboratory testing of such verification samples and test samples yields similar method random effects, such samples can be used to obtain precision data.

c) For blank samples, the laboratory can use blank samples without target components to establish control charts. In this case, the value of reagent blank should be deducted from the result of blank sample detection.

d) regular the test sample. If the laboratory proves that the precision of the results obtained by using the repeated test CRM matrix and standard solution, reference substance or internal quality control substance is far less than the precision of the regular test sample, the regular test sample shall be used as the verification sample. The prerequisite for using regular samples as verification samples is that the samples are stable in nature, constant in content, uniform enough and sufficient in quantity.

3. Verification frequency

The analysis tasks shall be divided into several categories such as high detection frequency, low detection frequency and special analysis, and the verification frequency of the analysis system shall be determined according to the following requirements:

a) The detection frequency is low, the number of samples in each batch is less than 20, and the concentration or content range of target components in the batch is small. In this case, a concentration or content point can be determined, and a control chart can be made at this concentration or content point. In the subsequent verification of the analysis system, at least one quality control sample is added to each batch of samples, and the single result or average value (repeated detection of multiple quality control samples) obtained is marked on the control chart to judge the stability of the analysis system.

B) The detection frequency is high, the number of samples in each batch is more than 20, and the concentration or content range of target components in the batch is small. In this case, it is also possible to determine only one concentration or content point and to create a control chart at this concentration or content point. In the subsequent verification of the analysis system, one quality control sample is added to each of the 20 test samples at intervals. The single result or average value (repeated detection of multiple quality control samples) obtained from the test is marked on the control chart to judge the stability of the analysis system.

c) The detection frequency is high, and the concentration or content range of the target component of the sample in the batch is large. In this case, at least two representative target component concentration or content levels should be determined, one should be close to a medium level of target component concentration or content, and the other should be close to a higher or lower target component concentration or content level. A control chart is made at these two concentration or content levels. In the subsequent verification of the analysis system, one quality control sample is added to every 20 test samples for each batch of samples. The single result or average value (repeated detection of multiple quality control samples) obtained from the test is marked on the control chart to judge the stability of the analysis system.

d) Special analysis. For some special analysis, the statistical control method may not be applicable. However, it can be assumed that the samples in the batch are of the same type, I .e. the errors are sufficiently similar. In this case, repeat the determination of all the tested substances, insert the blank control and add the appropriate number of quality control samples. Recovery tests can be carried out for different concentrations of the substance under suitable circumstances. Where appropriate quality control limits are not available, comparisons may be made using deviations or other criteria.

4. Analysis of system verification tools

1) The control chart verification and analysis system shall meet the following requirements:

a) The requirements for the verification of the analysis system using the control chart shall be specified in the SOP. Identify the types of control charts used and the methods for establishing and using control charts.

B) When establishing the control chart, the laboratory shall confirm that the analysis system is stable and can produce accurate and reliable test results. At the same time, the control concentration or content point shall be determined according to the requirements of verification frequency. The test should be repeated more than 25 times under reproducibility conditions and ensure that there are more than 20 qualified data before these results can be used to establish a control chart.

c) The quality control sample shall be mixed into the test sample in the form of blind sample to ensure that the test personnel carry out the test according to normal procedures to reflect the actual situation of the test process. The result analysis and judgment of quality control samples shall be completed by the personnel or departments responsible for quality management, and the analysis and judgment results shall be timely fed back to the inspection department or inspection personnel.

d) A control chart maintenance system shall be established, and the management and technical operation management shall regularly review the control chart. If there is a substantial change in the analytical system, the laboratory should re-establish the control chart.

2) Participating in the ability verification plan or measurement audit Participating in the ability verification or measurement audit plan is an effective measure for intermittent verification and analysis system, and should be carried out according to the following principles:

a) Participation in the laboratory proficiency testing plan is an indirect proof of the effective operation of the laboratory quality control system and the accuracy and reliability of the test results, but it cannot replace the internal quality control of the laboratory.

B) The laboratory shall reasonably arrange the plan for participating in the laboratory capability verification according to the scope of the testing capability, including the frequency of participation.

c) If no competency verification plan is available, a measurement review should be applied to a qualified laboratory.

3) Organize inter-laboratory comparison Organize inter-laboratory comparison to verify the analysis system, which shall meet the following requirements:

a) The organization of inter-laboratory comparison is an indirect self-certification of the effective operation of the laboratory quality control system and the accuracy and reliability of the test results, but it cannot replace the internal quality control of the laboratory.

B) in the case of not being able to participate in the ability verification plan or the measurement audit, the laboratory shall make its own inter-laboratory comparison plan. This standard refers to the selected comparison laboratory as the "participating comparison laboratory". The laboratory should make an accurate judgment on whether the participating comparison laboratories can obtain accurate and reliable test results. In order to facilitate the correct evaluation of the results, the participating comparison laboratories should not be less than 2.

c) Inter-laboratory comparison procedures shall be established and implemented after approval by relevant laboratory managers. In such procedures, it is particularly important to specify methods for evaluating test results, and the use of mathematical and statistical techniques in the judgment of results *.

5, measurement uncertainty in the laboratory internal quality zui control application.

The laboratory shall systematically assess the measurement uncertainty during the method verification or validation phase. During the use of the method, the measurement uncertainty should also be re-evaluated periodically. Give the following recommendations:

a) The measurement uncertainty assessed at the method verification or confirmation stage is the sum of all the error components of the method at the existing technical level of the laboratory, which is more scientific in the application of this to laboratory quality control activities. The laboratory should study and apply the application of measurement uncertainty in laboratory quality control.

B) It is recommended to combine measurement uncertainty with control charts as an effective tool for analytical system verification.