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WS/T 641-2018 PDF EnglishSearch result: WS/T 641-2018_English: PDF (WS/T641-2018)
WS/T641-2018 (WST641-2018): PDF in EnglishWS/T 641-2018 HEALTH INDUSTRY STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 11.020 C 50 Internal quality control for quantitative measurement in clinical laboratory ISSUED ON: DECEMBER 11, 2018 IMPLEMENTED ON: JUNE 01, 2019 Issued by: National Health and Wellness Committee of the People's Republic. Table of Contents Foreword ... 3 1 Scope ... 4 2 Terms and definitions ... 4 3 Preparation before internal quality control carried out ... 5 4 Design of internal quality control method ... 6 5 Actual operation of internal quality control ... 11 6 Management of internal quality control data ... 17 7 Quality control method of applicable patient data ... 18 8 Comparison between laboratories for internal quality control data ... 19 Annex A (informative) Common quality control rules and meanings ... 21 Annex B (informative) Power function diagram method ... 23 Annex C (informative) Operational process specifications diagram method .. 25 Bibliography ... 27 Internal quality control for quantitative measurement in clinical laboratory 1 Scope This Standard specifies the purpose of internal quality control for quantitative measurement items in clinical laboratory, the design of internal quality control method, the actual operation of internal quality control, the management of internal quality control data, the quality control method based on patient data as well as the comparison of internal quality control data between laboratories. This Standard is applicable to the quantitative measurement in clinical laboratory of the medical institution that carries out the clinical inspection service. 2 Terms and definitions For the purposes of this document, the following terms and definitions apply. 2.1 quality control a part of quality management that is committed to meeting quality requirements [GB/T 19000-2016, 3.2.10] 2.2 internal quality control the inspector, according to a certain frequency, continuously measure the specific components in a stable sample; use a series of methods to analyze; according to statistical law, infer and evaluate the reliability of the measurement results for this batch so as to determine whether the inspection report can be sent out; timely discover and exclude the dissatisfaction factors in quality link 2.3 quality control strategy quality control variety, testing frequency of each variety, position of placement, as well as rules for interpretation of quality control data and rules for determination whether the analysis batch is under control or out of control 2.4 measurement bias [JJF 1001 5.5] bias for short 3.3 Calibration The instrument used to measure clinical sample shall be calibrated according to some certain requirements. In calibration, select suitable (supporting) calibration product. If possible, ensure that test results are traceable to reference methods or/and reference materials. For different analysis items, it shall, according to the characteristics, establish their own calibration frequencies. 3.4 Quality control product 3.4.1 Characteristics The quality control product shall have the similar or same matrix with the testing sample of patient. The quality control product shall be uniform and stable. If conditions permit, store the quality control product that can be used for one year or more. The inter-bottle variability shall be less than the variation of analysis system. If there is no commercialized quality control product, the laboratory can make the quality control product by itself. 3.4.2 Analyte concentration in quality control product The concentration of selected quality control product shall be within the concentration range that is clinically meaningful. If the fixed-value quality control product is used, the original calibration value in the user’s manual can be only used as reference. It must be repeatedly measured by the laboratory to determine the tentative and common mean value as well as the standard deviation. 4 Design of internal quality control method 4.1 Quality control method selection and design form The quality control selection form is a 3×3 form. It determines quality control method that is applicable to nine different types of inspection procedures (quality control rules and number of quality control results per batch N). For single-rule fixed-limit quality control method, establish quality control selection and design form, for example, Levey-Jennings quality control chart. For multi- rule quality control method, establish quality control selection and design form, for example, multi-rule quality control method. Table 1 and Table 2 respectively show two quality control selection and design forms. The process capability of the form row is described by medically important systematic error (ΔSEc). The process stability of the form column is described by frequency of errors, f. new batch number shall be determined with the currently used quality control product. According to the results of at least 20 quality control measurements obtained by 20 or more independent batches (excluding abnormal values or outlying values), calculate average value as tentative mean value. Use this tentative mean value as the central line of next month’s internal quality control diagram for internal quality control. After one month, gather the under- control results of this month and the results of previous 20 quality control measurements. Calculate the accumulated average (the first month). Use this accumulated average as the average value of next month’s quality control diagram. Repeat the above operation process. Continue three to five months or continuously accumulate on a monthly basis. 5.1.1.2 Setting of common mean value Use the accumulated average number that is calculated by the first 20 data and all data collected by 3~5 months’ under-control data AS the common mean value of quality control product within validity period. And use it as the average number for future internal quality control diagram. For the individual item that the concentration level continuously changes within validity period, the average value needs adjusting constantly. 5.1.2 Quality control product of short stability Within 3~4 days, analyze 3~4 bottles per level of quality control products every day. Repeat 2~3 times per bottle. After data collection, calculate the average number, standard deviation and coefficient of variation. Inspect the abnormal value to data. If an abnormal value is found, it needs to recalculate the average number and standard deviation of the rest data. Use this mean value as the central line of quality control diagram. 5.2 Setting of control limit For quality control product that has new batch, it shall determine the control limit. The control limit is usually represented by the standard deviation multiple. 5.2.1 Quality control product of long stability 5.2.1.1 Setting of tentative standard deviation To determine the standard deviation, the quality control product that has new batch number shall be tested together with the currently used quality control product. According to the results of at least 20 quality control measurements obtained by 20 or more independent batches (excluding abnormal values or outlying values), calculate the standard deviation and use it as tentative 5.3.2 Frequency of quality control product inspection Within each analysis batch, at least perform one inspection for quality control product. The manufacturer of inspection system or reagent shall recommend the amount of quality control product for each analysis batch. User, according to different situation, may increase or reduce the number of quality control measurements. 5.3.3 Position of quality control product User shall determine the positions of each batch of internal quality control products. The principle is that before reporting the inspection results of a batch of patients, it shall evaluate the quality control results. When determining the position of quality control product, it must consider the type of analysis method and possible error type. For example, within the user specified batch length, perform non-continuous sample inspection. If the quality control product is put before the end of the specimen inspection, it may monitor the bias. If the quality control product is evenly distributed within the entire batch, it may monitor the drift. If it is randomly inserted in the patient sample, it may inspect the random error. In any case, it shall evaluate the quality control results before reporting patient inspection results. 5.3.4 Replacement of quality control product When it plans to replace the quality control product with new batch number, it shall be performed before the end of the “old” batch number of quality control product. Measure the new batch number of quality control product and “old” batch number of quality control product together. Repeat the processes of 5.1 and 5.2. Establish new mean value and control limit. 5.4 Drawing of quality control diagram and record of quality control results The quality control diagram is to measure and record the process quality, so as to assess and monitor if the process is under control. It is a diagram of a statistical method design. There are central line (CL), upper control limit (UCL) and lower control limit (LCL) on the diagram. There shall also be quality control results that are in chronological order or trace sequence of quality control results’ statistical value. According to the mean value and control limit of quality control product, draw Levey-Jenning quality control diagram (single concentration level), or Z-score diagram that different concentration levels are drawn on the same diagram or Youden diagram. Record the original quality control results on the quality control chart. Reserve the printed or electronic original quality control record. 5.5 Applicatio.......Source: https://www.ChineseStandard.net/PDF.aspx/WST641-2018 |