WS/T 404.6-2015Reference intertials for common clinical biochemistry tests. Part 6: Serum calcium, phosphorus, magnesium, iron (English PDF)

5.1 General principles

5.1.1 Clinical laboratories should first consider citing the reference interval of this document.

Note 1.The research workload and cost of establishing the reference interval are huge, and it is more realistic and feasible for clinical laboratories to quote the reference interval than to establish the reference interval by themselves.

Note 2.This reference interval is based on the results of a multi-center study of the Chinese adult population. The test results in the study can be traced to internationally recognized reference methods or reference materials.

See Appendix B.

5.1.2 The necessary verification or evaluation shall be carried out before using the reference interval of this document.

Note 1.The applicability of the external reference interval in the laboratory mainly depends on the comparability of the test results and the applicability of the population when the laboratory and the reference interval are established.

Note 2.Test results only have a constant system bias (correctness of test results) that affects the applicability of the reference interval. Excessive intra-laboratory variation is an experiment the quality of laboratory analysis is not a question of the applicability of the reference interval.

Note 3.The reference interval of this document is established based on the test results of serum. If the type of specimen used by the clinical laboratory is plasma, appropriate evaluation should be performed to determine Decide whether to use this reference interval.

5.2 Reference interval evaluation, verification and use

5.2.1 Perform reference interval evaluation and verification in accordance with the relevant provisions of WS/T 402.

5.2.2 If the laboratory confirmation is comparable to the test results when the reference interval is established and the population is applicable, the reference area of this document can be directly quoted If you are uncertain or need to verify the quoted reference interval based on the requirements of the laboratory management system, you can follow the steps below.

a) There are no less than 20 qualified reference individuals for screening, see A.2.2 for screening criteria;

b) Collect, process, and analyze samples according to the laboratory's operating procedures;

c) Check and eliminate outliers according to appropriate methods (if any, select another reference individual to fill in);

Note. The Dixon method is used for the outlier test. first sort the test results by size and calculate the range R, and then calculate the maximum and minimum values respectively the difference D between its adjacent value; if D/R>=1/3, the maximum or minimum value is regarded as an outlier and eliminated; the remaining data is repeated the previous step Carry out outlier test immediately until all outliers are eliminated.

d) If 20 qualified reference individuals are selected, compare the 20 test results with the reference interval. If the data beyond the reference interval does not exceed If there are more than 2, then the verification is passed; if there are more than 2, then another 20 qualified reference individuals will be selected and re-inspected in accordance with the above judgment standards.

certificate. If there are more than 20 reference individuals and the data exceeding the reference interval does not exceed 10%, the verification is passed; if the data exceeds 10% If the reference interval is exceeded, at least 20 qualified reference individuals shall be selected and re-verified in accordance with the above judgment standards. Validation results If it meets the requirements, the reference interval can be used directly, otherwise the reason should be found.

5.3 Procedure when the reference interval fails the verification

5.3.1 In the case of failure to pass the verification, the analysis quality, especially the accuracy, should be evaluated first, if it is confirmed that the analysis quality is caused by the detection system Problems, the analysis system should be improved or replaced. Analysis quality evaluation can adopt (but not limited to) the following methods.

a) Analyze interchangeable certified reference materials or other suitable reference materials;

b) Participate in the appropriate accuracy verification plan or standardization plan;

c) Compare with other systems or methods with reliable performance.

5.3.2 If it is proved that it is due to population reasons (such as ethnicity, high altitude areas, special living habits, etc.), the verification should be carried out according to WS/T 402 the requirements for establishing or citing appropriate reference intervals.

Appendix A

(Informative appendix) Information about the process of establishing the reference interval A.1 Steps to establish reference interval the reference interval of this document is established in accordance with the requirements of WS/T 402 using a multi-center research method, which mainly includes the following steps.

a) Select reference individuals to form a reference sample group;

b) Collect and process blood samples to obtain serum samples;

c) Test serum samples to obtain reference values;

d) Statistically process reference values and establish reference intervals.

A.2 Reference individual selection A.2.1 Selection of reference sample group the overall reference population for the design is the adult healthy population in my country, and the reference sample group is selected from 6 places in Northeast, North China, Northwest, East China, South China and Southwest China.

District urban and rural residents, the age range is 20-79 years old, the final selected reference individuals in the six regions total 4397 people, of which 1878 are males and 1878 are females.

Sex is 2519 people.

A.2.2 Selection of reference individuals each center recruits enough possible reference individuals in the region, obtains informed consent, and screens reference individuals to form a reference Sample group.

Select reference individuals through questionnaire surveys, physical examinations, and laboratory examinations to meet the following requirements.

a) Questionnaire survey, physical examination.

1) Consciously healthy;

2) Without the following diseases. acute and chronic infections (acute upper respiratory tract infection, pneumonia, tuberculosis, etc.), digestive system diseases (cirrhosis, liver Inflammation, fatty liver disease, gallstone disease, cholecystitis, chronic diarrhea, inflammatory bowel disease, etc.), kidney disease (chronic kidney disease, acute Kidney damage, etc.), metabolic and nutritional diseases (diabetes, metabolic syndrome, dyslipidemia and lipoprotein dyslipidemia, hyperuricemia Disease, gout, etc.), rheumatic diseases (rheumatoid arthritis, systemic lupus erythematosus, etc.), thyroid disease (thyroid function Hyperactivity, hypothyroidism, etc.), blood system diseases (anemia, leukemia, etc.), atherosclerosis and blood vessels Disease, heart disease, myopathy, malignant tumor, burns and muscle damage, obesity or weight loss [BMI (body mass index) >=28kg/m2 or < 18.5kg/m2], hypertension [systolic blood pressure >=140mmHg and/or diastolic blood pressure >=90mmHg];

3) No surgery within 6 months, no blood donation, blood transfusion or massive blood loss within 4 months, no medication within 2 weeks;

4) No malnutrition, vegetarianism, alcoholism (long-term drinking or heavy drinking within 2 weeks), smoking (smokers > 20 cigarettes/d);

5) No strenuous exercise or heavy physical labor recently;

6) The woman is not pregnant or breastfeeding.

b) Excluded by laboratory inspection.

1) Alanine aminotransferase >80U/L;

2) Triglyceride >=2.26mmol/L;

3) Total cholesterol >=6.22mmol/L;

4) Fasting blood glucose >=7.0mmol/L;

5) Hemoglobin. male < 120g/L; female < 110g/L;

6) HBsAg positive, anti-HCV positive, anti-HIV positive.

A.3 Blood sample collection and processing the principles of blood sample collection and processing are carried out in accordance with the relevant requirements of WS/T 225-2002.The specific requirements are as follows.

a) Reference individual preparation. Maintain normal living habits for 3 days before blood collection, do not do strenuous exercise and heavy physical labor. 1d dinner before blood collection Fasting from the next morning before blood collection, the fasting time is 8h~14h;

b) Blood collection. The subject takes a sitting position, uses a serum separation hose, and uses a vacuum blood collection method to collect blood from a vein in front of the elbow;

c) Blood sample processing. The serum is separated in time within 2 hours after the sample is collected, and the hemolysis, jaundice or chyle samples are checked and eliminated.

Analyze within 2h after departure.

A.4 Analysis of serum samples A.4.1 Analysis system Use a variety of analysis systems commonly used in clinical laboratories in my country.

Note. Refer to Appendix B for the analytical system used in the establishment of this reference interval and the metrological traceability of its detection results. The accuracy of the test results of each analysis system See A.4.2 for proof. Serum inorganic phosphorus Since there is no certified reference material of human serum matrix for verification and evaluation, the inorganic phosphorus reference interval in this document is based on the statistical results and comprehensive clinical opinion setting of test data in multiple analysis systems.

A.4.2 Analysis system performance evaluation the analysis system should perform analysis performance evaluation before reference individual serum samples are analyzed. According to the operating procedures specified in the instrument and reagent instructions Run the analysis system. Precision evaluation. Analyze two levels of quality control materials, determine 1 batch a day, repeat the determination 4 times, and determine the accuracy for 5 days;

Certificate. Analyze the comparison between the standard material SRM956c of the National Institute of Standards and Technology (NIST) and the Chinese national standard GB W09152 Calcium, magnesium, and iron are verified for accuracy. The precision and accuracy meet the relevant requirements of WS/T 403.

A.4.3 Serum sample analysis and quality control After the analytical performance meets the requirements, analyze the serum samples, and analyze each serum sample once. Precision control adopts two levels of quality control for substances, quality control material analysis is carried out before and after each independent analysis batch; the certified reference material SRM956c is analyzed monthly for accuracy control.

A.5 Reference value processing and reference interval establishment A.5.1 Outlier check Check and eliminate the outliers in each group according to the Dixon method.

A.5.2 Group judgment According to the nestedANOVA method, the group-group test is performed on the reference values of each group of gender, age, and region to determine whether grouping is needed, and there will be no need for classification the reference values of the groups are combined to determine the actual reference sample group.

A.5.3 Reference limit and reference interval establishment the middle 95% interval is used as the reference interval. Calculate the 2.5 percentile of the reference value of each actual reference sample group using non-parametric methods and 97.5 percentile as the reference lower limit and reference upper limit. According to clinical opinions, the reference limit is appropriately rounded to form a reference interval.

Appendix B

(Informative appendix) Measurement methods of serum total calcium, inorganic phosphorus, magnesium, iron and metrological traceability of the detection results the measurement methods of serum total calcium, inorganic phosphorus, magnesium and iron and the metrological traceability of the test results are shown in Table B.1.