Objective To estimate the assay performance of two different kind of reagent with different concentration of NADH.Methods Verificated function index of these two reagents,such as accuracy,sensitiveness,blank space and so on, and determined the molar extinction coefficient of NADH using hexokinase method and calculated the NADH density in two kind of AST reagents.Then estimated the effect of concentation of NADH on the analysis performance.Results NADH concentration was 0.21 mmol/L,and the sample detection limit of the linear was 1 629 U/L.NADH concentration was 0.13 mmol/L,and the sample detection limit of the linear was 1 263 U/L.So the gap between the two reagent’s detection linear was visible.But there were no significant changes in other performance indicators such as detection sensitivity,reagent blank,precision.Conclusion The NADH concentration in the reagent of AST had greatimpact on the detecting linear range, so should pay attention to the potential change of linear range in the daily work.

Objective To reflect the capability of the Chinese reference laboratories through the assessment and analysis of the uniformity and uncertainty for GGT , LDH, ALT and AST among RELA from 2006 to 2011.Methods To collect the measurement results and the combined measurement uncertainties of all laboratories that had participated in RELA during 2006 and 2011.The testing results and uncertainties of the four enzymes among RELA were grouping analyzed.They were divided into four groups:the whole group ( all laboratories , 12-27 labs annual ) , the foreign group ( laboratories except for the Chinese laboratories , 4-10 labs annual ) , the Chinese group ( all Chinese laboratories , 6-18 labs annual ) and the reference group ( LAB 3 ).Calculate the CVs of inner-group measurement results , the bias of the Chinese group and the reference group measurement results to the foreign group and the elative standard measurement uncertainties , and evaluate the uniformity of measurement results and the ur variation trends.Results There were annual downtrend for coefficient of variation except LDH.Except ALT in 2006, CVs of the foreign group , the Chinese group and the whole group were all below 5%.The Chinese group had 87.5%(42/48) smaller CV than the foreign group in the last 6 years.The biases of the Chinese group to the foreign group were from-2%to 2%except GGT and ALT in 2006 and ALT in 2008.The Chinese group had 66.7% results less than the foreign group during 2006 and 2011.There was significant differences between the Chinese group measurement results ( 3.525 μkat/L ) and the foreign group ( 3.647 μkat/L ) of ALT high batch in 2008 (T=2.635,P<0.05).The relative standard measurement uncertainties of the four groups had the same uptrend and the low batch was 10% higher than the high batch.The reference group had a stable ur of 1.2%.The Chinese group had a lower ur than the foreign group during 2007 and 2009, but had similar levels after 2010.The Chinese group had constant relative standard uncertainties of 1.0% in 2009, 2010 and 2011.Conclusions There was no significant differences between the Chinese group and the foreign group, and they had good uniformity .The results of the relative standard measurement uncertainty were objective and stable.

Objective We aim to evaluate the value of the current serum creatinine reference interval ( RI ) provided by Industry Standard WS /T 404.5 in clinical practice.Methods The first time serum creatinine levels and urinary albumin /creatinine ratio were obtained from 67 605 adult patients ( <60 years old) who were treated in the First Hospital of China Medical University between October 1, 2014 and September 30, 2015 in this cross-sectional study.Estimated glomerular filtration rate ( eGFR ) calculated by chronic kidney disease epidemiology collaboration (CKD-EPI) equation and urinary albumin /creatinine ratio (ACR) were used to evaluate the clinical practical significance of current and old serum creatinine RIs as the criteria.Results 4.3% of normal subjects based on current RI were showed decreased eGFR, 98% of abnormal subjects based on the current RI were founded to have decreased eGFR . 1378 subjects were evaluated as increased based on current RI but as normal based on old RI , and 93.5% of these subjects were showed decreased eGFR .In addition, ACR was measured in 26 cases, and 18 out of 26 cases (69.2%) were confirmed to have elevated ACR (≥30 mg/g) and proteinuria.On the other hand of analysis, screening positive rates of declined eGFR were 43.6% by old RI and 61.9% by current RI in the subjects with eGFR under 90 ml(min ×1.73 m 2 ), and the performance of the current RI was obviously improved(χ2 =212.648,P <0.001).Conclusions The current reference interval of serum creatinine is favorable for the detection of renal dysfunction in patients .It is recommended that the current reference interval can be applied in the clinical laboratories as early as possible .

Objective To verify and monitor the performance of accuracy, precision and comparability of 26 clinical biochemical analytes (29 methods) in the six centers involved in multi-centers reference intervals research, and to ensure the reliability of theirmeasurement results.Methods During the period of the systems evaluating, two levels of commercial quality control materials and fresh frozen human serum reference materials were applied to verify the performance of inter-laboratory precision and accuracy of analysis systems. During the period of samples testing, the commercial quality control materials were measured whenever samples were analysed, the fresh frozen serum reference materials were measured once a month.The coefficient of variations (CVs), bias and total errors were calculated to assess the precision, accuracy and comparability.Results Verification of precision and accuracy: ( 1 ) the ranges of CVs of 29 methods in the six laboratory laboratories were 0.4%-6.0%, the CVs of all 29 methods met the criterion . (2) The overall average bias of the analysis systems of 21 analytes (24 methods) ranged from -5.15%( ALT) to 4.46% ( Ur ) .Among 24 methods the overall average bias of TP, Glu-GOD, Ur, Cl, Ca exceeded the acceptable range.The quality assessment during the period of samples testing:(1) The overall average bias ranged from -1.95%(Ca) to 2.92%(Ur), median 1.26%, they all met the requirements of relevant standards.( 2 ) When commercial control materials were tested, the requirements of CVs were fulfilled for most methods in the six laboratories,and the CVs of TP, Alb, Cl, Ca exceeded the acceptable range.The overall average TE of all methods met the quality specification for the C-N controls material.For the C-P control material, only the overall average TE of TP (5.05%) exceeded thearceptable range while the other methods met the requirement in criterion.Conclusions The performance of precision and accuracy of the analysis systems used in the six laboratories passed the verification.During the period of sample testing, the performance of precision and accuracy of the most methods in the 6 laboratories met the requirements of quality specifications, and the overall performance was good.Because of the limitation of current technology the performance of some methods didn't fulfill the requirement of specifications, and need to be improved.

Objective: To establish the information solution for the classification and assessment of specimen quality based on the assembly line. Methods: Before the samples entered into the assembly line, they were took pictures and screened by the image results. For the suspected samples, serum index was detected. Then, the classification criteria of specimen quality were set, and the alarm thresholds of serum indices for each item suitable for our laboratory were established. The results of serum indices were compiled into the corresponding text descriptions and automatically written into the notes of the result reports. The pictures of blood collection tubes were stored in the laboratory information management system (LIMS) and could be accessed at any time for verification. The samples intercepted by the automatic review were further reviewed by manual. Results: The intra-assay coefficients of variation (CV) of serum indices for haemolysis (H), lipaemia (L) and icterus (I) were 0.6%, 0.7% and 1.3%, respectively, indicating that the precision was good. Among 657 770 samples detected by the assembly line, 11.9% of samples were screened out before they entered the assembly line. The detection of serum indices of these samples demonstrated that the samples with haemolysis, lipaemia and icterus accounted for 1.6%, 1.2% and 0.3% of the total samples, respectively. According to the results of the interference experiment, the alarm threshold of hemolytic serum index was set in 11 items, and those of lipaemia and icterus were set in 1 item. Conclusion By establishing the information solution of specimen quality based on the assembly line, the real-time classification prompting of specimen quality is realized, and the missed detection is avoided, which is helpful to reduce the pre-analysis errors caused by serum quality and simplify the laboratory workflow.