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Objective To improve the detection ability of laboratories, and to identify possible technical defects in the detection of dichloroacetic acid and trichloroacetic acid in drinking water. Methods A number of laboratories were organized to conduct interlaboratory determination of dichloroacetic acid and trichloroacetic acid in drinking water. Prefabricated standard series and intermediate samples were distributed. Data of determination were collected and statistically analyzed to evaluate the detection results. Results The slopes of dichloroacetic acid and trichloroacetic acid working curves were analyzed by Grubbs test. The analysis results showed that there were 1 outlier in the dichloroacetic acid data and 3 outliers in the trichloroacetic acid data, respectively. The determination results of the spiked samples of dichloroacetic acid and trichloroacetic acid were 1.5 and 4 times the actual value, respectively. Conclusion This investigation reveals that there exist some technical problems in the direct determination of dichloroacetic acid and trichloroacetic acid by gas chromatography, such as inappropriate selection of chromatographic conditions and injection port flow control, and incorrect way of spiking internal standards.
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Objective:To understand the salt sales situation and salt iodine content in the market of Guizhou Province 3 years after the system reform of salt industry.Methods:From August to October 2020, in 9 cities (prefectures) of Guizhou Province, 2 counties (cities and districts) were selected from each city (prefecture), 1 urban area and 1 township were selected from each county (city and district), 1 large supermarket and 1 farmers' market were selected in the urban area, and 1 small supermarkets or convenience stores were selected in the township, to check the varieties, place of origin and iodine content label on the package of salt sold, and different brands of salt were collected and sent to the provincial and county salt iodine laboratories. The iodine content was determined and analyzed.Results:A total of 18 large supermarkets, 18 farmers' markets and 18 small supermarkets or convenience stores were investigated, and 70 salt samples of 23 brands, 3 types and origin from 11 provinces were collected. Among them, there were 56 samples with iodine content of 21 - 39 mg/kg on the package. The iodine content range of provincial detection was 19.23 - 37.41 mg/kg (two of them were lower than 21.0 mg/kg), and the median was 25.75 mg/kg. There were 12 samples of two iodine contents (18 - 33 and 21 - 39 mg/kg) marked on the package, and the salt iodine range of provincial detection was 23.52 - 32.90 mg/kg, with a median of 26.55 mg/kg. One sample was marked with 18 - 33 mg/kg, and the iodine content of provincial detection was 25.20 mg/kg; the iodine content of 1 sample of non-iodized salt was not detected. According to the actual test value, iodine contents of 68 samples were within the range of packaging marks, accounting for 97.14% of the total. Taking the provincial test results as a standard, the absolute value of the relative deviation of the provincial and county test results was 0 - 27.45%, the average deviation was 7.65%, and the coincidence rate was 91.43% (66/70). The county test results were acceptable.Conclusions:After the system reform of salt industry, there are many kinds of salt which come from many provinces, and more than 97% of the salt iodine content which is within the standard range of salt concentration in Guizhou Province.
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OBJECTIVE: To analyze the comparison results of volatile organic components in chemicals tested by occupational health laboratories.METHODS: A total of 37 reference laboratories that participated in the 2019 National Occupational Health Inspection and Testing Institution Laboratory Comparison Chemical Qualitative Testing Comparison organized by Guangdong Occupational Health Testing Center were selected as the research subjects. Headspace gas chromatography-mass spectrometry was used for the determination of volatile organic components in chemicals. The comparison results of reference laboratories were collected and implemented with qualitative and quantitative evaluation. RESULTS: The qualified rates of the qualitative results of the required hazard factors and other hazard factors in the reference laboratories were higher than those of the quantitative results of similar factors with statistical significance(83.78% vs 67.57%, 89.19% vs 56.76%, all P<0.05). There was no significant difference in the qualified rate of qualitative and quantitative results and comprehensive judgment results among each reference laboratory with other hazard factors(83.78% vs 89.19%, 67.57% vs 56.76%, 83.78% vs 89.19%, all P>0.05). The qualified rate of 37 reference laboratories was 89.19%(33/37). It showed no significant difference in the qualified rate of qualitative, quantitative and comprehensive judgment results among the reference laboratories of disease prevention and control system and non-disease prevention and control system(93.75% vs 85.72%, 85.00% vs 61.91%, 93.75% vs 85.52%,all P>0.05). CONCLUSION: There are great differences in the detection ability of volatile organic components on chemicals of each reference laboratory. The ability of qualitative detection is superior to the quantitative detection.
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OBJECTIVE: To analyze the influence of noise measuring skills by continuous inter-laboratory comparison among occupational hygiene technical service organizations. METHODS: The results of 68, 55 and 50 occupational hygiene technical service organizations(reference organizations) participating in the inter-laboratory comparison of workplace noise measurement in 2014, 2017 and 2018 respectively were collected. The measurement operation and the calculation of equivalent sound level were evaluated according to the GBZ/T 189.8-2007 Measurement of Physical Agents in Workplace--Part 8: Noise.The measured results were analyzed by z score evaluation method. RESULTS: The results of noise measurement field operation of the reference organizations in the year 2014, 2017 and 2018 show that the accuracy rates of instrument setting was 89.7%, 98.2% and 100.0%, the accuracy rates of measuring position were 52.9%, 81.8% and 94.0%, the accuracy rates of sound level meter holding were 54.4%, 80.0% and 92.0%, the accuracy rates of microphone pointing were 98.5%, 98.2% and 94.0%, and the accuracy rates of noise type recognition were 83.8%, 92.7% and 84.0%, respectively. Among them, the accuracy of instrument setting, measurement position and sound level meter holding showed an increasing trend year by year(P<0.01). The pass rates of measurement results were 91.2%, 94.5% and 88.0% in 2014, 2017 and 2018 respectively. The pass rates of equivalent sound level calculation were 73.5%, 92.7% and 88.0%. The pass rates of comprehensive evaluation were 70.6%, 89.1% and 80.0% respectively. Among them, the pass rates of equivalent sound level calculation and comprehensive evaluation in 2017 were higher than that in 2014(P<0.017). There was no significant difference in the three-year comprehensive assessment total pass rate between private organizations and non-private organizations(84.0 % vs 75.5%, P>0.05). There was no significant difference in the total pass rate of three-year comprehensive evaluation between non-Pearl-River-Delta organizations and Pearl-River-Delta organizations(70.3% vs 81.6%, P>0.05). CONCLUSION: Continuous inter-laboratory comparison in occupational hygiene technical service organizations is beneficial to improve on-site noise measure capability.
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OBJECTIVE: To analyze the inter-laboratory comparison results of occupational hygiene laboratories of Guangdong Province. METHODS: The 42 laboratories that continuously participated in the inter-laboratory comparison of occupational hygiene technical service institutions in Guangdong Province from 2014 to 2018 were selected as the research subjects Guangdong Occupational Health Test Center from 2014 to 2018 were selected by convenient sampling method. The data of detection of organic compounds, metal element, non-metal element in the workplace air, detection of metal element in biological materials, and the detection of free silica in dust were analyzed. The results were statistically analyzed by four-point robust statistical technique. RESULTS: From 2014 to 2018, a total of 1 205 items of sample detection results were submitted in these 5 years. The qualified rate of sample test was 92.4%(1 114/1 205) in these laboratories. The qualified rate of test of organics in workplace air, metals in workplace air, inorganic non-metals in workplace air, metals in biological materials and free silica in dust were 93.3%, 94.4%, 91.6%, 84.4% and 91.8% respectively. There was no significant difference in the qualified rate of sample test between the laboratories in the Pearl River delta in Guangdong Province and the laboratories in other regions the laboratories in other regions(92.8% vs 89.6%, P>0.05). There was no significant difference in the qualified rate of sample test among the occupational disease prevention and treatment institute, center for disease control and prevention and private laboratories(93.1% vs 93.6% vs 89.0%, P>0.05). Among the 91 unqualified items, 35 items were │z score of inter-laboratory(z_B)│≥ 3(38.5%), 40 items were │z score of within-laboratory(z_w)│≥ 3(44.0%), and 16 items were│z_B│≥ 3 and │z_w│≥ 3(17.6%). CONCLUSION: The laboratories in Guangdong Province that participated in the inter-laboratory comparison of occupational health test for 5 consecutive years have a relatively high level of occupational health testing, and the test results are accurate.
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OBJECTIVE: To evaluate the diagnostic ability of toxicity pathology in patho-toxicological testing institutions in China. METHODS: The institutions participated in the 2018 Interlaboratory Comparison Activity of Toxicity Pathology Testing(hereinafter referred to as reference unit) were selected as the research subjects. The heart, spleen, skin, soft tissue, liver and mammary gland of SD rats of different groups in the 2-year carcinogenesis test were selected. The femur, knee joint and nose of Beagle dogs in the 4-week toxicity test and a total of 10 pathological tissues were selected as the comparison samples. The pathological diagnosis was carried out by the pathological diagnostic personnel of the reference unit, and the diagnostic results were reported. The expert appointed by the Toxicology and Pathology Committee of Chinese Toxicology Association compared the diagnostic results with the appointed value. RESULTS: A total of 167 pathological diagnostic personnel from 75 reference units in 24 provinces and municipalities participated in the comparison activity. The reference units were mainly distributed in East China, South China and North China, accounting for 77.3%(58/75). Totally 75 reference units fed back 750 effective diagnostic results. The qualified rates of diagnosis on heart, spleen, skin, soft tissue and breast samples were higher than 60.0%. The qualified rates of diagnosis on femur and knee joint, and nose samples were low(30.7% and 6.7%, respectively). There were 1(1.3%), 46(61.4%) and 28(37.3%) reference units rated as unqualified, qualified and excellent, respectively. CONCLUSION: Most of the testing institutions in China have a high level of patho-toxicological diagnostic ability, that can provide reliable diagnostic results for toxicology safety evaluation tests.
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OBJECTIVE: To analyze the results of inter-laboratory comparison among occupational hygiene laboratories. METHODS: A convenient sampling method was used. The laboratories participating in the inter-laboratory comparison organized by the Guangdong Occupational Health Test Center from 2013 to 2017 were selected as study subjects. The data of detection of organic compounds, metal element, inorganic non-metal element in workplace air, detection of metal element in biological materials, and detection of free silica in dust were analyzed. The results were statistically analyzed by four-point robust statistical technique. RESULTS: A total of 615 laboratories(times) participated in the comparison, and 2 785 items of sample detection results were submitted from 2013 to 2017.Among them, a total of 2 484 items were tested qualified and the sample test qualified rate was 89.2%. The test qualified rates of organics in workplace air, metals in workplace air, inorganic nonmetals in workplace air, metals in biological materials and free silica in dust were 91.1%, 92.0%, 86.6%, 80.4% and 85.0%, respectively. The sample test qualified rates of the laboratories in different regions from high to low were: the laboratories Pearl River Delta region in Guangdong Province, the laboratories in non-pearl river delta region in Guangdong Province and the laboratories outside of Guangdong Province were 91.6%, 87.2% and 72.6%(P<0.01), respectively. The sample test qualified rate of the public laboratories was higher than that of the private laboratories(90.3% vs 87.0%, P<0.05). CONCLUSION: The accuracy of the occupational hazard factor test in the participating laboratories needs to be improved. It is necessary to further strengthen the investment, supervision and management to non-pearl river delta region laboratories and private laboratories in Guangdong Province.
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Objective To construct the schistosomiasis diagnostic reference laboratory in Jiangsu Province, and to examine the role and diagnostic efficiency of the reference laboratory. Methods A schistosomiasis diagnostic reference laboratory was built in Jiangsu Province according to the requirements of the construction of the national schistosomiasis diagnostic reference laboratory in China. Inter-laboratory comparisons were conducted and the diagnostic capability of grassroots laboratories was evaluated in Jiangsu Province. Results The organization structure, environmental conditions, administration and quality systems of the schistosomiasis diagnostic reference laboratory in Jiangsu Province all met the requirements for construction of the national schistosomiasis diagnostic reference laboratory in China, and the schistosomiasis diagnostic reference laboratory in Jiangsu Province was issued a certificate of a province-level schistosomiasis diagnostic reference laboratory. During the 6 inter-laboratory comparisons performed by national schistosomiasis diagnostic reference centers of China, the qualitative and quantitative results of each detection item were all in agreement with the reference samples (Kappa = 1), and the diagnostic capability was identified excellent. The results of indirect hemagglutination assay of 426 serum samples from 4 grassroots laboratories were re-examined, and the mean coincidence rate was 94.13% (range, 92.08% to 96.25%) with the grassroots laboratories, with a mean Kappa value of 0.85 (range, 0.83 to 0.86) and a mean missing rate of 10.19% (range, 0 to 17.65%). Conclusions The schistosomiasis diagnostic reference laboratory has been successfully established and effectively operated in Jiangsu Province, which plays an active role in improving the capability of schistosomiasis diagnostic equality in the province.
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Objective To construct the schistosomiasis diagnostic reference laboratory in Jiangsu Province, and to examine the role and diagnostic efficiency of the reference laboratory. Methods A schistosomiasis diagnostic reference laboratory was built in Jiangsu Province according to the requirements of the construction of the national schistosomiasis diagnostic reference laboratory in China. Inter-laboratory comparisons were conducted and the diagnostic capability of grassroots laboratories was evaluated in Jiangsu Province. Results The organization structure, environmental conditions, administration and quality systems of the schistosomiasis diagnostic reference laboratory in Jiangsu Province all met the requirements for construction of the national schistosomiasis diagnostic reference laboratory in China, and the schistosomiasis diagnostic reference laboratory in Jiangsu Province was issued a certificate of a province-level schistosomiasis diagnostic reference laboratory. During the 6 inter-laboratory comparisons performed by national schistosomiasis diagnostic reference centers of China, the qualitative and quantitative results of each detection item were all in agreement with the reference samples (Kappa = 1), and the diagnostic capability was identified excellent. The results of indirect hemagglutination assay of 426 serum samples from 4 grassroots laboratories were re-examined, and the mean coincidence rate was 94.13% (range, 92.08% to 96.25%) with the grassroots laboratories, with a mean Kappa value of 0.85 (range, 0.83 to 0.86) and a mean missing rate of 10.19% (range, 0 to 17.65%). Conclusions The schistosomiasis diagnostic reference laboratory has been successfully established and effectively operated in Jiangsu Province, which plays an active role in improving the capability of schistosomiasis diagnostic equality in the province.
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Objective@#To development of ethylene glycol samples in silicone tubes, and the samples were applied to inter-laboratory comparison, through it to evaluate the detection capacity of occupational health testing laboratories.@*Methods@#Three content levels of ethylene glycol samples in silicone tubes were prepared, and the homogeneity and stability of samples were investigated, the results were statistically analyzed. A robust statistical four-point distance method was used to calculate the results submitted by each participant laboratory and the test capability of the laboratory was assessed by the z-score method.@*Results@#The statistic of the homogeneity of ethylene glycol samples in silicone tubes were less than the critical value (P>0.05) , and the samples were stable at room temperature for one month. The satisfactory rate of comparison between 204 laboratories was 88.24%.@*Conclusion@#The homogeneity and stability of the ethylene glycol samples in the silicone tubes can meet the requirements of proficiency testing and can be used for laboratory comparison. Most of the laboratories that participated in the comparison had the ability to detect ethylene glycol.
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Objective To evaluate the urinary iodine detection ability of Iodine Deficiency Disorder Laboratory in Shaanxi Province,and to test the quality of laboratory construction.Methods In Shaanxi Province,ten city-level and 107 county-level urinary iodine labs of Center for Disease Control and Prevention or Institute for Endemic Disease Prevention and Control were selected in 2018,and two urinary iodine quality-control samples were measured by As3+-Ce4+ catalytic spectrophotometry.The results of urinary iodine quality control were evaluated through standard Z score generated from all the participatory labs.Results All 117 labs had feedback their testing results.There was one lab with an inter-laboratory |Z| score≥3,and 3 labs with inter-laboratory |Z| score≥3,and the qualified rate was 96.58％ (113/117).In 107 county-level urinary iodine labs,there was one lab with an interlaboratory | Z| score ≥ 3,and 3 labs with inter-laboratory | Z[score ≥ 3,and the qualified rate was 96.26％ (103/107).Conclusions The construction of urinary iodine lab has achieved great results in Shaanxi Province,the testing ability of iodine determination laboratory is maintained at a high level,which has laid a solid foundation for prevention and treatment of iodine deficiency disorders in Shaanxi Province.
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OBJECTIVE: To evaluate the interlaboratory comparison results of noise measuring instruments in the occupational hygiene technical service institutions. METHODS: The basic performance data, multi-frequency acoustic calibration measurement results and simulated workplace noise at fixed points of 60 noise measuring instruments were collected. The instruments were from 60 occupational health technical service institutions who participate in the inter-laboratory comparison study in noise measuring instruments. The results of the measurements were analyzed using quartile robust statistical technology and z score evaluation method.RESULTS: All 60 participating comparison noise measuring instruments were examined or calibrated, and 58 instruments(96.7%) were used within the term of validity of examination or calibration. The 58 instruments were tested by multi-frequency noise calibration measurement. The comparative passing rate of the instrument accuracy was 94.8%(55/58); and the linearity test passing rate was 87.9%(51/58). There were 59 instruments participated in the simulated workplace noise at fixed points. The z-score pass rate of the two comparison measurement points was 89.8%(53/58). A total of 57 enterprises participated all the instrument performance comparison tests, with a pass rate of 94.7%(54/57). CONCLUSION: Performance of noise measuring instruments from the occupational hygiene technical service institutions is generally good. However, there are a small number of instruments have poor accuracy and linearity, and there are measurement bias that require improvement.
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Objective@#Through inter-laboratory comparison to analysis and evaluation of the detection capacity of arsenic in the urine. @*Methods@#Urine arsenic samples were prepared with normal human urine as matrix. The homogeneity of the samples was investigated and the results were statistically analyzed by single factor analysis of variance. 2 samples were issued to each participant laboratory. A robust statistical four-point distance method was used to calculate the results submitted by each participant laboratory and the test capability of the laboratory was assessed by the z-score method. By means of method experiments and records, the reasons of dissatisfaction and the influencing factors of the results were discussed. @*Results@#The statistic of the homogeneity of urine arsenic samples was less than the critical value (P>0.05) , which showed that the arsenic in the sample was homogeneous. The satisfactory rate of comparison between 36 laboratories was 86.1%. The main reasons for dissatisfaction were the testing conditions and the quality control measures. The selection of sample pretreatment, acidity control and hydrogenation conditions was the main influencing factor for the determination of urinary arsenic by atomic fluorescence spectrometry. @*Conclusion@#The level of urinary arsenic detection in the occupational health laboratories was generally better and a few laboratories need to be improved ability of detection. It was very important to control the test conditions reasonably and strengthen the quality control measures to improve the accuracy of urine arsenic detection.
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OBJECTIVE: To observe the diagnostic capacity and its influencing factors in the toxicologic pathology diagnostic laboratories in China. METHODS: Inter-laboratory comparison of toxicologic pathology diagnosis was cosponsored by Chinese Society of Toxicology-Toxicologic Pathology Specialty Section and Guangdong Province Hospital for Occupational Disease Prevention and Treatment. Nine digital slices of digestive system lesions were screened as comparison samples,and the reference institution with toxicologic pathology diagnostic laboratories completed the diagnosis within the prescribed time. According to the three grades of “excellent”,“satisfaction”and “dissatisfaction”,the evaluation was carried out.RESULTS: A total of 74 reference institution participated in this comparison,which distributed in 20 provinces and 4 municipalities and 156 pathologists. The reference institutions were mainly distributed in North China,Southern China and East China. There was an average of 2 pathologists per laboratory,and in the quantity of academic title,the junior,intermediate,and senior was 15,70 and 46 persons respectively. Parasitic hepatocyte cysts( 97. 3%),adenocarcinoma of small intestine( 95. 9%) and polyarteritis nodosa of the pancreas( 89. 2%) had the highest rate of “excellent”grade,while the duodenal gland inflammation( 67. 6%),foam cell aggregation in colonic propria( 40. 5%) and hepatoma adenoma( 32. 4%) had the highest rate of dissatisfaction grade in the evaluation of single case. In the overall evaluation,reference laboratories reached the “excellent”grade and the “satisfaction”grade were 78. 4% and 21. 6% respectively.The number of pathologists provided by each reference laboratory had impacts on the overall evaluation level and the single case evaluation( neoplastic lesions) in the evaluation of single case( P < 0. 05). The types of the reference laboratory,the regional distribution and the grade of the academic title had no effect on the diagnostic ability( P > 0. 05). CONCLUSION: The reference laboratory is superior in diagnosing the digestive system lesions in the inter-laboratory comparison activity.The number of pathologists in the reference laboratory is one of the influencing factors of its diagnostic ability.
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OBJECTIVE: To evaluate the feasibility of the inter-laboratory comparison of microwave radiation measuring instruments which uses cellphone signal shielding device as standard source,and to establish inter-laboratory comparison method of microwave radiation.METHODS: The typical sampling method has been used by selecting twenty-one measuring instruments of microwave radiation from 21 occupational hygiene technical service organizations as study subjects.A cellphone signal shielding device was applied as standard source.Measurement points were measured by surveyors at a distance of 1.0 and 1.5 meter to the standard source,and the measurement results were analyzed by four robust technology and z-score evaluation method.RESULTS: Stability test showed that there was no statistical difference among the power density of standard source which were measurement at three diffluent time [(26.10 ± 0.94) vs(25.78 ± 0.27) vs(25.83 ±0.47) μW/cm~2,P>0.05].The standard source stability can also satisfy the requirement of inter-laboratory comparison.Among the 21 selected equipments,one of the 21 measuring instruments was not calibrated,one calibration certificate of the instruments was expired,and one calibration result of the instruments was unqualified.The z score of inter-laboratory(z_B) of 21 measuring instruments ranged from-1.27 to 4.85,while z score of within-laboratory(z_w) ranged from-1.42 to 2.18.One | z_B| of the instruments was above 3.00,while | z_W| was above 2.00.Comprehensive evaluation of the above results showed that only one instrument was unqualified.CONCLUSION: It is feasible that a cellphone signal shielding device could be applied as standard source.The method developed in this study can be used to understand the performance of microwave radiation instruments.
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OBJECTIVE: To evaluate the technical level and ability of the detection of free silica in dust in occupational health technical service institutions of Guangdong Province through inter-laboratory comparison. METHODS: The interlaboratory detection of free silica in dust in 55,61,58 and 66 occupational health technical service institutions were carried out and compared in 2012-2015. The results were statistically analyzed by four points robust statistical technique,and the relative deviation between the laboratory test results and the Median of them was used as the auxiliary evaluation index of the laboratory's technical ability. RESULTS: The stable coefficient of variation(CV) of samples with free silica content > 20. 00% was less than 5. 00%,and the stable CV of samples with free silica content ≤20. 00% was more than5. 00%. The qualified rate in 2012-2015 were 89. 09%,81. 97%,77. 59% and 81. 82%,respectively. There was no statistical difference(P > 0. 05) in the annual reference between private and non-private institutions compared to the qualified rate in 2012-2015. There was no statistical difference(P > 0. 05) in the qualified rate of the institutions in the Pearl River Delta region and in the non-triangular regions of the Pearl River Delta in 2012-2015. CONCLUSION: Comparison of the detection technology service ability in the detection of free silica in dust should be conducted to improve its technical service quality.
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Objective To find out the detection level of the blood routine test in clinical laboratories of basic medical institutions in Hefei ,and to analyze the results of inter‐laboratory comparison among township health centers and community health service cen‐ters in Hefei and explore the main factors .Methods Forty‐three township health centers and community health service centers were randomly selected to conduct field investigations and take blood routine test inter‐laboratory comparison .Results Both 41 .9% of the passing rate and the average score 72 .37 points in Inter‐laboratory comparisons were significantly lower than the An‐hui province clinical inspection center(94 .1% and 95 .97 points) ,the differences were statistically significant(P<0 .05);Comparing to the results of the Anhui province clinical inspection center ,there was statistically significant difference on parameter(WBC ,RBC , Hb ,HCT ,PLT) average pass rate of blood routine test(P<0 .05);the personnel primary education was low ,18 .80% of the staff in clinical laboratories were not professionals ;most of blood analyzers were domestic and 53 .49% of all instruments had been used for more than 5 years;the overall laboratory quality management level was low .Conclusion The blood routine test detection level in clinical laboratories of basic medical institutions in Hefei was far below than that of secondary and tertiary medical institutions .The daily laboratory internal quality control should be strengthened and the quality management system should be improved gradually .
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OBJECTIVE: To identify the characteristics and application conditions of currently statistical methods for inter-laboratory comparison and proficiency testing results analysis in drug control, combining with the international standards and practical application. METHODS: Based on the ISO/IEC 17043-GB/T28043, start beging with the definition of outliers, the methods currently used in inter-laboratory comparison and proficiency testing results analysis both at home and abroad methods were summarized and compared according to the ISO/IEC 17043-GB/T28043, with focused on the testing the stability and repeatability of laboratory testing proficiency. The most-used stastical methods of mter-laboratory comparison and proficiency testing during present domestic and international drug testing was sumarrized and contratively analyzed. RESULTS: The application conditions of different methods good contrast were providedidentified application condition of methods. CONCLUSION: Robust Z-score has more advantages in current stage of inter-laboratory comparison and proficiency testing results analysis.
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OBJECTIVE: To explore rational statistical methods for analysis of the results of inter-laboratory comparisons, which will be helpful to improve the statistical analysis ability of organizers of proficiency testing project against pharmaceutical laboratories. METHODS: Robust statistical Z-score method and iterative computation method were used to analyze the assay result of cefminox sodium powder for injection respectively, and the critical statistical parameters of the two methods were compared. RESULTS: The critical statistical parameters of robust statistical Z-score method anf iterative computation method were as follows: the robust average were 77.71% and 77.63%, the robust standard deviation were 0.66 and 0.67, and the coefficients of variation were 0.85% and 0.86%, respectively. CONCLUSION: It is very important to select the correct statistical approach to evaluate the proficiency of pharmaceutical testing laboratories. By comparing the steady average and the median value of Z-score, the range of best estimates for the true value can be found, and the judgment for the outliers can be more accurate.
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OBJECTIVE: To evaluate the major influence factors affecting the quality and accuracy of measuring instruments for power frequency electromagnetic fields in occupational hygiene technical service organizations by developing interlaboratory comparison in workplaces. METHODS: Six measuring instruments for power electromagnetic fields from 6occupational hygiene technical service organizations in Guangdong Province were selected by typical sampling method. A high-voltage substation was selected as a standard source. We set measurement sites underneath it as inter-laboratory comparison spots for power frequency electromagnetic fields. The stability of the standard source was evaluated by pairedsamples t-test and measure results were analyzed by z-score evaluation method based on quartile robust statistical technology. RESULTS: During and after the inter-laboratory comparison,the intensity of electric field and magnetic field of the standard source showed no significant difference [( 555. 03 ± 2. 94) vs( 555. 68 ± 3. 20) V / m,( 2. 30 ± 0. 06) vs( 2. 29 ± 0. 07) μT,P > 0. 05],which met the demand of stability of inter-laboratory comparison. The data of electric field measured by 2 measuring instruments without remote-reading system were found to be high because of proximity effect from its handheld status. The z-score of inter-laboratory( zB) of other 4 measuring instruments with remote-reading system ranged from- 0. 52 to 1. 10,while the z-score of within-laboratory( zW) ranged from- 1. 28 to 0. 37,and both results of| zB| and | zW| were satisfactory( < 2. 00). The zBof power frequency magnetic field measured by the 6 measuring instruments ranged from- 0. 67 to 1. 26,while zWranged from- 0. 59 to 0. 90,and both | zB| and | zW| were also satisfactory( < 2. 00). CONCLUSION: It is feasible that the inter-laboratory comparison of measuring instruments of power frequency electromagnetic fields could be implemented by a high-voltage substation as a standard source. The measuring instruments without remote-reading system could be used to measure the intensity of magnetic field but not the electric field. The measuring instruments with remote-reading system could be used to measure the intensity of either the electric field or the magnetic field,and the measurement results are satisfactory.