Objective:To learn about the detection quality and external quality control assessment of fluoride and arsenic in laboratories at all levels in Qinghai Province.Methods:The Z-score method was used to analyze and evaluate the evaluation results of 1 provincial, 8 municipal and 43 county level laboratories of disease prevention and control institutions participating in the external quality control assessment of water fluoride and brick tea fluoride in Qinghai Province in 2021, as well as 1 provincial, 1 municipal and 2 county level laboratories of disease prevention and control institutions participating in the external quality control assessment of water arsenic and urine arsenic. The feedback rate and qualification rate of external quality control of each assessment laboratory were calculated.Results:In 2021, the feedback rate of external quality control of water fluoride, brick tea fluoride, water arsenic and urine arsenic in provincial and municipal level laboratories of Qinghai Province were 100.00%; except that the qualified rate of water fluoride was 7/9, the qualified rate of external quality control of other projects was 100.00%. The feedback rate of external quality control of water fluoride, brick tea fluoride, water arsenic and urine arsenic in county level laboratories was 100.00%; except that the qualified rate of water fluoride was 86.05% (37/43), the qualified rate of external quality control of other projects was 100.00%. In the specific assessment results of the laboratory, the assessment results of water fluoride sample FS20210101 from 1 provincial, 1 municipal and 2 county level laboratories, and FS20210102 from 1 county level laboratory were suspicious; the assessment results of water fluoride sample FS20210101 from 3 county level laboratories were not satisfactory; the assessment results of fluoride and arsenic sample in other laboratories were satisfactory.Conclusions:The qualified rate of external quality control of fluoride and arsenic in laboratories at all levels in Qinghai Province is relatively high, but some county level laboratories are still dissatisfied with the assessment results of water fluoride. Therefore, it is necessary to strengthen the detection level of water fluoride in laboratories.

Objective:To analyze the external quality control assessment results of urinary iodine, salt iodine and water iodine in iodine deficiency disorders laboratories in Qinghai Province, to evaluate the testing capacity of provincial, municipal and county-level laboratories and the operation of external quality control network, so as to provide quality assurance for consolidating and eliminating iodine deficiency disorders.Methods:In 2021, 1 provincial, 8 municipal, and 43 county-level laboratories in Qinghai Province had participated in the assessment of urinary iodine and salt iodine, while 1 provincial and 8 municipal-level laboratories had participated in the assessment of water iodine. The assessment results were evaluated using the method of reference value ± uncertainty of external quality control samples.Results:All laboratories that participated in the assessment had provided feedback. One provincial-level laboratory passed the assessment of urinary iodine, salt iodine, and water iodine. Among 8 municipal-level laboratories, 2 laboratories failed the urinary iodine assessment, with a pass rate of 6/8; the assessment of salt iodine and water iodine in 8 laboratories were all qualified. Among 43 county-level laboratories, 7 laboratories failed the urinary iodine assessment, with a pass rate of 83.7% (36/43); the assessment of salt iodine in 43 laboratories were all qualified.Conclusions:The external quality control network of iodine deficiency disorders laboratories in Qinghai Province has fully covered all municipal and county-level laboratories. The testing capability of provincial-level laboratory is stable and maintains a high level; the testing quality of some municipal and county-level laboratories is still unstable and needs to be further strengthened.

Objective:To analyze the results of serum erythropoietin (EPO) in adults patients with Kaschin-Beck disease (KBD) in Qinghai Province.Methods:According to the "Diagnosis of Kaschin-Beck Disease" (WS/T 207-2010), by using clinical examination and X-ray, adults over 20 years old in KBD areas of Xinghai County and Guide County, Hainan Tibetan Autonomous Prefecture, Qinghai Province, were divided into KBD case group ( n = 109) and internal control group ( n = 95) in July 2019. At the same time, healthy people were selected as external control group ( n = 90) in Xunhua County. Then 2 ml fasting cubital venous blood was collected from the target population to separate serum. The serum EPO level was determined by enzyme-linked immunosorbent assay (ELISA). Results:There was no significant difference in age and sex ratio among the 3 groups ( F = 0.73, P = 0.484; χ 2 = 1.03, P = 0.611). There was significant difference in serum EPO levels among the 3 groups [KBD case, internal and external control groups: (30.74 ± 26.23), (19.73 ± 11.53) and (10.83 ± 4.48) U/L, F = 26.51, P < 0.001]. Multiple comparisons showed that there were statistically significant differences in serum EPO levels between KBD case group and the internal and external control groups ( P < 0.05), but there was no significant difference between the internal and external control groups ( P > 0.05). Conclusions:The serum EPO level in adult KBD patients in Qinghai Province is increased significantly.

Objective:To analyze the external quality control assessment results of fluoride in brick tea in the provincial, city (prefecture) and county (city, district)-level endemic fluorosis laboratories in Qinghai Province, and to evaluate the testing capabilities of laboratories at all levels.Methods:The Z-score method was used to analyze and evaluate the results of provincial, city (prefecture) and county (city, district)-level laboratories that participated in the external quality control assessment of fluoride in brick tea in Qinghai Province from 2014 to 2020, and│Z│≤2 was qualified; 2 <│Z│ < 3 was basic qualified; │Z│≥3 was unqualified.Results:From the feedback, the feedback rate of external quality control of fluoride in brick tea in provincial and city (prefecture)-level laboratories in Qinghai Province from 2014 to 2020 was 100.00%; the feedback rate of county (city, district)-level laboratories from 2014 to 2018 was 100.00%, and there were no feedback units in 2019 and 2020. From the assessment of qualification, the qualification rate of provincial, city (prefecture)-level laboratories was 100.00% in all other years except one unit failed in 2017; the qualification rate of county (city, district)-level laboratories was 100.00% in 2014, 2015, 2016 and 2019, and there were 6 unqualified units in other years.Conclusions:From 2014 to 2020, some endemic fluorosis laboratories in Qinghai Province still fail to pass the external quality control assessment of fluoride in brick tea. In the future, it will be the focus of work to strengthen personnel training and improve the detection ability.

Objective:To evaluate the water fluoride detection ability of county (city, district) level (referred to as the county-level) laboratories in Qinghai Province.Methods:During the "13th Five-Year Plan" period (2016 - 2020), 4, 4, 4, 43, 43 county-level laboratories in Qinghai Province were organized to participate in the national water fluoride external quality control assessment, and the assessment results were evaluated by Z-ratio scoring method.Results:The response rate of county-level laboratories was 86.05% (37/43) in 2019, and 100.00% in other years. The qualified rate of county-level laboratories was 100.00% from 2016 to 2018; in 2019 and 2020, the assessment was fully covered, and the qualified rate was 81.40% (35/43) and 95.35% (41/43), respectively. Compared with 2019, the response rate and qualified rate in 2020 increased significantly, and the differences were statistically significant (χ 2 = 6.450, 4.074, P < 0.05). In the past 5 years, two assessment samples│Z│ < 1 in each laboratory were the most common, but with two assessment samples 2≤│Z│ < 3 in some qualified laboratories. Conclusion:The consistency of water fluoride determination in Qinghai Province is not very ideal, and the detection ability of county-level laboratories still needs to be strengthened.

Objective:To investigate the dietary iodine intake of people in different areas of Qinghai Province, and to provide the basis for scientific iodine supplementation and continuous elimination of iodine deficiency hazards.Methods:From 2018 to 2019, according to administrative division, natural geographical regions, population distribution and economic development level of Qinghai Province, a total of 14 survey sites were selected. One village was selected from each survey site, and 20 households were selected from each village, the salt samples and 24 h urine samples of all family members were collected to detect salt iodine and urinary iodine. One drinking water sample was collected at the five directions of east, west, south, north and middle of each village to detect water iodine. Salt iodine was detected by direct titration, urinary iodine and water iodine were detected by arsenic-cerium catalytic spectrophotometry. At the same time, the 3-day weighing method was used to investigate the diet, the daily dietary iodine intake per capita (the result was expressed as average) and the proportion of dietary iodine in urinary iodine were calculated, the daily dietary iodine intake per capita of different production modes (agricultural region and pastoral region), different geographical environment (Hehuang Valley, Qaidam Basin, Qilian Mountain and Qingnan Plateau), different nationalities (Han, Tibetan, Hui, Mongolian, Tu, Salar) and different economic levels (< 8 000, 8 000 -, 10 000 -, ≥12 000 Yuan) were compared.Results:A total of 999 people from 280 families were surveyed, including 511 males and 488 females. The median water iodine of each survey site was less than 10 μg/L, all of which were environmentally iodine-deficient areas. A total of 280 salt samples were collected, the median salt iodine was 26.0 mg/kg, and the consumption rate of qualified iodized salt was 100% (280/280). A total of 999 urine samples were tested, and the median urinary iodine of people was 192.5 μg/L, which was at an appropriate level of iodine. There was no statistically significant difference ( t =-1.599, P > 0.05) in the daily dietary iodine intake per capita (28.53, 33.44 μg) of people in agricultural region ( n = 643) and pastoral region ( n = 356). The daily dietary iodine intake per capita (25.38, 33.30, 32.98, 34.79 μg) of people in Hehuang Valley ( n = 448), Qaidam Basin ( n = 125), Qilian Mountain ( n = 157), and Qingnan Plateau ( n = 269) were compared, the difference was statistically significant ( F = 2.883, P < 0.05); among them, the daily dietary iodine intake per capita in Hehuang Valley was lower than that in Qingnan Plateau ( P < 0.05). The daily dietary iodine intake per capita of different nationalities were compared, the difference was statistically significant ( F = 3.647, P < 0.05), Salar ( n = 68) and Tibetan ( n = 239) were higher (37.21 and 32.21 μg). The daily dietary iodine intake per capita (38.97, 17.01, 30.86, 33.14 μg) of annual per capita disposable income < 8 000 ( n = 194), 8 000-( n = 221), 10 000-( n = 302), ≥12 000 Yuan ( n = 282) were compared, the difference was statistically significant ( F = 9.407, P < 0.05). The proportions of dietary iodine in urinary iodine of various population ranged from 5.35% to 15.54%. Conclusions:The iodine nutrition of people in Qinghai Province is suitable, the dietary iodine intake of people is closely related to geographical environment, nationality and economic level. But the proportion of dietary iodine in urinary iodine is relatively low, the consumption of iodized salt is still the main way for people to intake iodine, and it is also the main measure to continuously eliminate the harm of iodine deficiency in Qinghai Province.

Objective:To verify the revised method of cerium sulfate catalytic spectrophotometry for iodide index of "Standard Examination Methods for Drinking Water-Nonmetal Parameters" (GB/T 5750.5-2006).Methods:From July to September 2019, the Laboratory of Department for Endemic Disease Prevention and Control of Qinghai Institute for Disease Prevention and Control verified the revised method (determination of iodide in drinking water by cerium sulfate catalytic spectrophotometry) of cerium sulfate catalytic spectrophotometry (hereinafter referred to as original method) in "Standard Examination Methods for Drinking Water-Nonmetal Parameters" (GB/T 5750.5-2006). The revised method was verified according to the requirements of "Standard Examination Methods for Drinking Water-Water Analysis Quality Control" (GB/T 5750.3-2006), including standard curve, detection limit, precision, accuracy and actual sample determination.Results:The linear range of the revised method was 0 - 20.0 μg/L, the correlation coefficient was - 0.999 4 - 0.999 8, and the detection limit was 0.231 μg/L. The relative standard deviation ( RSD) of low, medium and high iodine water samples of 6 times detection ranged from 1.4% to 9.6%, and the recoveries of low and medium water samples ranged from 89.0% to 108.0%. The detection results of national first-class reference materials for iodine composition analysis in water were within the range of standard value ± uncertainty. There was no significant difference in the test of results of 12 tap water samples between the revised method and the original standard method ( t = - 0.075, P > 0.05). Conclusion:The revised method has a good linear relationship of standard curve, high precision and accuracy, and good reproducibility, is simple and easy to operate, and is suitable for promotion and application.

Objective:To understand the water iodine content in Qinghai Province and draw a distribution map of water iodine, so as to provide a basis for scientific supplementation of iodine and continuous elimination of iodine deficiency hazards.Methods:In 2017, in all counties (cities, districts) in Qinghai Province, with townships (towns, streets, referred to as townships) as the unit, the residents' drinking water samples were collected, water iodine content was tested, the median water iodine was calculated, and the water iodine distribution map of Qinghai Province was drew.Results:Totally 1 836 drinking water samples were collected in 392 townships, the median water iodine was 1.7 μg/L. Townships that had the median water iodine < 5 μg/L, in the range of 5 to 10 μg/L and > 10 μg/L accounted for 80.6% (316/392), 17.1% (67/392) and 2.3% (9/392), respectively. Among all townships, the highest of the median water iodine was 24.8 μg/L. Based on the results, water iodine distribution map of Qinghai Province, water iodine distribution map of Xining City and water iodine distribution map of Haidong City were compiled.Conclusions:Iodine deficiency is widespread throughout natural environment in Qinghai Province. Hence, salt iodization measures to prevent iodine deficiency disorders should be implemented continuously. According to the water iodine distribution map, the people should be guided to supplement iodine scientifically.

Objective:To detect serum Col2-3/4 C-terminal cleavage product of type Ⅱ collagen (C2C) and pyridinoline (PYD) among brucellosis patients at early period, and to provide a better understanding of the changes of bone and joint collagen metabolism in the early stage of brucellosis.Methods:From 2013 to 2016, 61 cases of brucellosis patients at early period (within 6 months) from brucellosisout patient of Qinghai Institute for Endemic Disease Prevention and Control were selected as case group, and 67 cases of healthy volunteers were selected as control group. Serum C2C and PYD levels in all samples were measured simultaneously with enzyme linked immunosorbent assay (ELISA).Results:The median serum C2C of patients with early brucellosis was 83.45 ng/ml and that of the control group was 73.35 ng/ml. There was significant difference in serum C2C between the case group and the control group ( Z = 5.027, P < 0.05). The median serum PYD of patients with early brucellosis was 278.45 nmol/L and that of the control group was 212.75 nmol/L. There was significant difference in serum PYD between the case group and the control group ( Z = 6.967, P < 0.05). Conclusion:Serum C2C and PYD levels of brucellosis patients at early period are increased.

Objective:To analyze the assessment results of the external quality control in iodine deficiency disorders laboratories at all levels in Qinghai Province so as to provide quality assurance for monitoring and control effect evaluation of iodine deficiency disorders.Methods:The results of urinary iodine, salt iodine, and water iodine quality control assessments at the provincial, city (state) and county-level iodine deficiency disorders laboratories were analyzed in Qinghai Province from 2013 to 2018 (sourced from the annual evaluation results issued by National Reference Laboratory for Iodine Deficiency Disorders). Among them, there were 1 provincial, 8 city (state) and 43 county-level (2017, 2018) laboratories participated in the urinary iodine assessment; 1 provincial, 8 city (state) and 30 county-level (43 in 2017 and 2018) laboratories participated in the salt iodine assessment; 1 provincial and 8 city (state)-level laboratories participated in the water iodine assessment.Results:From 2013 to 2018, the feedback rates and qualified rates of provincial and city (state)-level laboratories participated in the urinary iodine external quality control assessment were 100.0%; the feedback rates of 43 county-level laboratories (2017 and 2018) were 100.0%, and the qualified rates were 93.0%(40/43) and 88.4%(38/43), respectively. The feedback rates and qualified rates for salt iodine assessment in provincial and city (state)-level laboratories were 100.0%; the county-level laboratories feedback rates were 100.0%, and the qualified rates were > 90.0% except for 2014. And the feedback rates of provincial and city (state)-level laboratories for water iodine assessment were 100.0%; the qualified rate of provincial-level laboratory was 100.0%, and the city (state)-level laboratories were 100.0% except 2016 (7/8).Conclusions:The quality control network of Qinghai Province's iodine deficiency disorders laboratories has fully covered all city (state) and county-level laboratories. Provincial, city (state)-level laboratories have stable and reliable levels of urinary iodine, salt iodine, and water iodine; some individual county-level laboratories testing capabilities still need to be improved.