Dynamic changes in liver function tests do not correctly reclassify patients at risk of choledocholithiasis beyond ASGE 2019 criteria.

Introduction: Dynamic changes in liver function tests have been proposed to correctly reclassify the risk of choledocholithiasis; however, information is scarce and insufficient to recommend its use. Methods: Retrospective cohort of patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) due to moderate and high risk of choledocholithiasis according to the 2019 American Society of Gastrointestinal Endoscopy (ASGE) guidelines. We evaluated whether significant changes in liver function tests (bilirubin, transaminases, or alkaline phosphatase), defined as an increase or a reduction ⩾30 or ⩾50% between two measurements taken with a difference of 24-72 h can correctly reclassify the risk of choledocholithiasis beyond the ASGE guidelines. The net reclassification index (NRI) was calculated for patients with and without choledocholithiasis. Results: Among 1175 patients who underwent ERCP, 170 patients were included in the analysis (59.4% women, median 59.5 years). Among patients without a diagnosis of choledocholithiasis, the number of patients correctly reclassified by transaminases was slightly higher than those incorrectly reclassified (NRI = 0.24 for aspartate amino transaminase and 0.20 for alanine amino transaminase). However, among patients with a diagnosis of choledocholithiasis, it led to incorrect reclassification in a greater number of cases (NRI = -0.21 and -0.14, respectively). The benefits of reclassification were minimal for bilirubin and alkaline phosphatase, or for value changes >50%. A subgroup analysis showed similar findings in patients without a history of cholecystectomy and in those with normal bile duct. Conclusion: Dynamic changes in liver function tests do not improve choledocholithiasis risk classification beyond the 2019 ASGE criteria. New criteria should continue to be sought to optimize risk stratification.

Performance evaluation of some domestically produced biochemical reagents / 中华检验医学杂志

Objective:To evaluation the performance of a total of 40 clinical biochemical reagents from three domestic manufacturers and two foreign manufacturers, and evaluate their clinical application value.Methods:The Beckman AU5400 automatic biochemical analyzer was used to verify the performance of 40 kinds of commonly used clinical biochemical reagents from three domestic manufacturers of Sichuan Maccura, Ningbo Medical System, and Shanghai Fosun Long March, and two foreign imported manufacturers of Roche and Japan′s Hitachi. The analysis samples were selected from the serum of patients who underwent clinical testing in Nanjing Drum Tower Hospital hospital from December 2021 to June 2022. Refer to China′s national health industry standards, China′s national pharmaceutical industry standards, the US Clinical Laboratory Standards Institute (CLSI) for the performance evaluation standards of in vitro diagnostic reagents, and the methods recommended in the relevant regulations of China′s State Food and Drug Administration on the management of in vitro diagnostic reagents. The precision, linear range, open bottle stability, interchangeability of calibrators and accuracy from different batches of 40 reagents were evaluated and validated. Simple linear regression analysis was used for linear regression, and P<0.05 indicated that the regression was statistically significant. Results:The overall precisions of 40 reagents were fine, except for one domestic reagent with low-level intra-batch coefficient of variation ( CV) exceeding the range declared in the specification. The intra-and inter-batch CVs of the remaining reagents were all smaller than those declared in their respective specifications. The linear ranges of domestic reagents and imported ones have achieved the linear ranges declared by each manufacturer. There were no statistical differences on the measurements between the reagents from open bottle of 30 days and the corresponding new ones for 40 reagents( P>0.05). The test values of domestic reagents and imported reagents after exchange of different batches of calibrators were within the ranges declared by each manufacturer. Both domestic reagents and imported reagents have passed the accuracy verification. Conclusions:The performance index of 27 biochemical detection indicators of the three domestic manufacturers are basically consistent with those of imported reagents, meeting the requirements of clinical biochemical laboratories. However, the bottle opening stability and anti-interference performance of some detection reagents needs to be improved.

The Value of Lactate Dehydrogenase in Predicting Rhabdomyolysis-Induced Acute Renal Failure; a Narrative Review.

INTRODUCTION: Determining the diagnostic value of available biomarkers in predicting rhabdomyolysis-induced acute kidney injury (AKI) is a priority. This study aimed to review the current evidence about the value of lactate dehydrogenase (LDH) in this regard. METHODS: In this narrative review, the papers in PubMed, Embase, and web of science were studied. The keywords prognosis, prognoses, prognostic, LDH, rhabdomyolysis, emergency patients, and acute kidney failure or AKI had been selected from MeSH medical dictionary. Related papers written in English and published from November 2007 to December 2020 were selected. RESULTS: Finally, 14 articles were accepted for analysis. Among the selected articles, four were randomized clinical trials, seven were cross-sectional, and three were case-control studies. The results of the present review showed that abuse of illegal drugs is the most common cause of rhabdomyolysis. AKI is the most serious complication of rhabdomyolysis reported in the studies. These studies have shown a three-fold increase in AKI following drug-induced rhabdomyolysis. The review of the included articles shows that high LDH can predicts AKI, especially in critical and emergency situations such as rhabdomyolysis where there is a risk of death if diagnosed late. These studies show that LDH increases in the presence of renal failure and tissue damage. CONCLUSION: Serum LDH is an appropriate and cost-effective prognostic indicator that can be used for risk classification of patients at risk for rhabdomyolysis-induced AKI.

Acurácia diagnóstica entre teste rápido da urease e estudo histopatológico para detecção de Helicobacter pylori / Diagnostic accuracy of urease quick test compared to histopathological study for Helicobacter pylori detection

Objetivo: Analisar a acurácia do teste rápido da urease para detecção de Helicobacter pylori comparado com o exame histopatológico. Métodos: Estudo prospectivo e descritivo realizado de abril de 2018 a maio de 2019 em um Serviço de Endoscopia e Biliopancreática e em um laboratório de patologia. A amostra foi composta de 64 pacientes, de ambos os sexos, com idade de 35 a 81 anos, que apresentavam queixas dispépticas. Foram realizados exame histopatológico e teste rápido da urease. Os dados foram analisados pelo R Core team 2019 e submetidos a análises descritivas (variáveis categóricas) e inferenciais (teste de associação de qui-quadrado de Pearson e teste de Mann-Whitney). O nível de significância adotado foi de 5%. Resultados: O teste rápido da urease demonstrou que dez pacientes foram verdadeiros-positivos, 39 verdadeiros-negativos, três falsos-positivos, 12 falsos-negativos, com sensibilidade de 45,4% (25,1% a 67,3%), especificidade de 92,9% (79,4% a 98,1%), valor preditivo positivo de 76,9% (45,9% a 93,8%), valor preditivo negativo de 76,5% (62,2% a 86,7%), acurácia de 76,6% (64,0% a 85,9%), razão de chance diagnóstica 10,8 (2,56 a 45,9), índice de Youden 0,38 (0,16 a 0,60) e taxa de erro de 23,4% (14,1% a 36,0%). Conclusão: O teste rápido da urease apresentou baixa capacidade de detectar pacientes infectados, menor acurácia em relação ao estudo anatomopatológico e alta especificidade. O teste pode ser útil no momento da realização da endoscopia, por fornecer resultado rápido e barato para detectar H. pylori. O diagnóstico da bactéria apresenta maior confiabilidade com a realização dos dois métodos para pesquisa de H. pylori.

Objective: To analyze the accuracy of the rapid urease test for Helicobacter pylori detection when compared with the histopathological examination. Methods: This is a prospective and descriptive study conducted from April 2018 to May 2019, at an Endoscopy and Biliopancreatic Service and in a pathology laboratory. The sample consisted of 64 male and female patients aged 35 to 81 years old with dyspeptic complaints. Histopathological examination and rapid urease test were performed. Data were analyzed by R Corel team 2019 and underwent descriptive (categorical variables) and inferential (Pearson's Chi-squared association test and Mann-Whitney test) analyzes. The significance level adopted was 5%. Results: The rapid urease test showed that ten patients were true positive, 39 true negative, three false-positive, and 12 false-negative, and sensitivity was of 45.4% (25.1% to 67.3%), specificity 92.9% (79.4% to 98.1), positive predictive value of 76.9% (45.9-93.8%), negative predictive value of 76.5% (62.2% to 86.7%), accuracy of 76.6% (64.0% to 85.9%), diagnostic odds ratio of 10.8 (2.56% to 45.9), Youden index 0.38 (0.38% to 0.60), and error rate 23.4 (14.1% to 36.0%). Conclusion: The rapid urease test showed low ability to detect infected patients, lower accuracy compared to the pathological study, and high specificity. The test may be useful at the time of endoscopy, as it provides a quick and inexpensive result to detect H. pylori. The diagnosis of the bacterium is more reliable when both methods for H. pylori investigation are performed

Doença de chagas: uma atualização bibliográfica / Chagas disease: a bibliographic update

É uma doença infecciosa causada por um protozoário parasita chamado Trypanosoma cruzi,nome dado por seu descobridor, o cientista brasileiro Carlos Chagas, em homenagem a outro cientista, também brasileiro, Oswaldo Cruz. Essa doença é conhecida popularmente como doença do coração crescido, além disso, os locais com mais índices dessa doença são as regiões do Norte e Sudeste e tem como formas de diagnósticos exames de sorologiaparasitários e xenodiagnóstico. E uma das principais formas de prevenção da doença vem sendo o uso de telas e repelentes.

It is an infectious disease caused by a protozoan parasite calledTrypanosoma cruzi, named after its discoverer, the Brazilian scientistCarlos Chagas, in honor of another scientist, also, Brazilian, Oswaldo Cruz. This disease is popularly known as a disease of the heart grown, in addition, the sites with the most indexes of this disease are the regions of the North and southeast and have as diagnostic methods serologica tests parasitic and xenodiagnosis. And one of the main forms of prevention of the disease has been the use of screens and repellents.

Dynamic liver test patterns do not predict bile duct stones.

BACKGROUND: Numerous models have been developed to predict choledocholithiasis. Recent work has shown that these algorithms perform suboptimally. Identification of clinical predictors with high positive and negative predictive value would minimize adverse events associated with unnecessary diagnostic endoscopic retrograde cholangiopancreatography (ERCP) while limiting the use of expensive tests including magnetic resonance cholangiopancreatography (MRCP) and endoscopic ultrasound (EUS) for indeterminate cases. METHODS: Consecutive unique inpatients who received their first ERCP at Los Angeles County Medical Center between January 2010 and November 2016 for suspected bile duct stones were reviewed. The primary outcome was the proportion of patients with specific combinations of liver enzyme patterns, transabdominal ultrasound, and clinical features who had stones confirmed on ERCP. As a secondary outcome, we assessed the performance of the American Society for Gastrointestinal Endoscopy (ASGE) risk stratification algorithm in our population. RESULTS: Of the 604 included patients, bile duct stones were confirmed in 410 (67.9%). Detailed assessment of liver enzyme patterns alone and in combination with clinical features and imaging findings yielded no highly predictive algorithms. Additionally, the ASGE high-risk criterion had a positive predictive value of only 68% for stones. For the 236 patients for whom MRCP was performed, this imaging modality was shown to have highest predictive value for the presence of stones on ERCP. CONCLUSION: Exhaustive exploration of various threshold values and dynamic patterns of liver enzymes combined with clinical features and basic imaging findings did not reveal an algorithm to accurately predict the presence of stones on ERCP. The ASGE risk stratification criteria were also insensitive in our population. Though desirable, there may be no "perfect" combination of clinical features that correlate with persistent bile duct stones. MRCP or EUS may be considered to avoid unnecessary ERCP and associated complications.

Relationship between Paraoxonase-1 and Arylesterase Enzyme Activities and SYNTAX I and II Scores in Patients with ST-Elevation Myocardial Infarction.

Background: Although serum paraoxonase-1 (PON-1) and arylesterase (ARE) activities are linked to the presence of stable coronary arterial disease, their correlation with SYNTAX Score I (SS1) and SYNTAX Score II (SS2) has not been known well. Our aim was to determine the association between PON-1 and ARE activities, together with the genetic polymorphism of PON-1, and both SS1 and SS2 in patients with acute ST-segment elevation myocardial infarction (STEMI). Methods: Consecutive patients with acute STEMI (n=102: 78 male, 24 female; mean age=61.14±12.25 y) admitted to the Emergency Department of Kirsehir Ahi Evran University Hospital between August 2018 and December 2018 were enrolled. PON-1 and ARE activities were determined on hospital admission. The SS1 and SS2 scores were calculated by using the angiographic and clinical data. Subsequently, the relationships between the activities of the enzymes, together with the genetic polymorphism of PON-1, and both SS1 and SS2 were interrogated. Results: The mean SS1 and the mean SS2 were 19.8±9.7 and 32.3±11.5, respectively. The phenotype distributions of PON-1 were Q192Q (n=60), R192Q (n=35), and R192R (n=7). The respective PON-1 (U/L) and ARE (kU/L) activities were 514.85±29.34 and 216.82±36.72 in the low SS1 category; 527.60±56.31 and 203.95±55.97 in the intermediate SS1 category; and, 690.10±11.07 and 238.48±45.65 in the high SS1 category.PON-1 and ARE activities did not correlate with the SS1 categories, and varying SS2 scores. The distribution of the Q192R polymorphism was homogenous among the different SS1 and SS2 scores. The localization of acute STEMI also did not associate with the activities of either enzyme. Conclusion: Admission serum PON-1 and ARE activities, together with the PON-1 Q192R genetic polymorphism, showed association neither with SS1 and SS2 nor with the localization of infarction in our acute STEMI patients.

Asociación entre niveles patológicos de amiloide A sérico y periodontitis / Association between serum amyloid A pathologic levels and periodontitis

Fundamento: la proteína amiloide A sérica es producida en respuesta a la liberación de citoquinas por parte de monocitos y macrófagos, después de un estímulo de fase aguda como es la infección. Objetivo: determinar los niveles séricos de amiloide A y su asociación con pacientes diagnosticados con periodontitis crónica. Métodos: se realizó un estudio observacional de corte transversal, el universo estuvo constituido por 80 pacientes con periodontitis crónica y 28 personas sin periodontitis como grupo control. El diagnóstico de periodontitis crónica se basó en criterios definidos con anterioridad. Todos los participantes respondieron un cuestionario relacionado con características sociodemográficas. Para calcular los niveles de amiloide A sérico se realizó una prueba de ensayo enzimático. Resultados: los niveles de amiloide A sérico patológicos se asociaron con la periodontitis (p=0,002) y se correlacionaron de manera significativa con mayor edad (r=2,42; p=0,01); sin embargo, la regresión logística ajustada por edad mostró asociación estadística significativa solo con periodontitis (OR=5,6; intervalo de confianza del 95 % 1,7-19). Conclusiones: la probabilidad de presentar niveles patológicos de amiloide A sérico en pacientes con periodontitis crónica es seis veces la de los pacientes sin periodontitis, lo cual podría ser un factor de riesgo para enfermedades cardiovasculares.

Background: serum amyloid A protein is produced in response to the cytokines released by monocytes and macrophages after an acute-phase stimulus such as infection. Objective: to determine the serum levels of amyloid A protein and its association with patients diagnosed with chronic periodontal disease. Methods: a cross-sectional observational study was conducted. The universe was composed of 80 patients with chronic periodontitis and 28 people without periodontal affections as a control group. Diagnosis of chronic periodontal disease was based on criteria stated previously. All the participants answered a questionnaire related to sociodemographic characteristics. A clinical enzymatic trial was carried out to calculate the levels of pathological serum amyloid A. Results: pathological levels of serum amyloid A were associated with periodontitis (p=0,002) and were correlated significantly with older age (r=2, 42; p=0, 01). Nevertheless, logistic regression adjusted by age showed remarkable statistical association only with periodontal disease (OR=5, 6; interval from 95 % 1, 7-19). Conclusions: probability of presenting pathological levels of serum amyloid A in patients with chronical periodontal disease is six times the one of the patients without this affection. That could me a risk factor for cardiovascular diseases.

Thrombophilia testing in a tertiary paediatric hospital: Indications, outcomes and appropriateness.

AIM: The association between inherited thrombophilia and thrombotic disease in children is unclear. As a result, whether expensive thrombophilia tests are indicated in children is a contentious issue. This retrospective study aimed to assess the appropriateness of thrombophilia testing and the associated cost of inappropriate testing at a tertiary paediatric hospital. METHODS: We conducted a search for thrombophilia tests ordered at the Royal Children's Hospital between 1 January 2011 and 31 December 2013. Using pathology and clinical records, we collected data relating to demographics, clinical data, indications, requesting departments and impact on patient management. RESULTS: Over the 3-year period, 3867 tests were ordered for 613 patients costing the hospital $102 579. Tests were most commonly ordered by gastroenterology on patients receiving liver transplants, by neurology as part of the stroke protocol, and by cardiology and cardiac surgery for patients anticoagulated on heparin infusions. Testing for thrombosis-related indications was relatively uncommon. Thrombophilia testing only directly affected management in one-third of patients. Overall, 70% of thrombophilia tests ordered were considered appropriate. However, some departments were found to have rates of inappropriate testing in excess of 50%. CONCLUSION: With improvements in thrombophilia testing practices at the Royal Children's Hospital AU$29 645.40 could be saved over 3 years. While there are improvements to be made in this area, in the overall context of the hospital's pathology testing budget, review of other areas such as inappropriate use of low-cost, high-volume tests may be of greater value in reducing the cost of pathology testing.

Evaluation of serum sialic acid detection kit using enzymic method and investigate the clinical diagnosis value of sialic acid / 中华检验医学杂志

Objective To evaluate the performance of serum sialic acid detection kit using enzymic method and investigate the clinical diagnosis value of sialic acid.Methods one hundred and fifty healthy adults were enrolled in this case control study to establish serum SA reference interval.The analytical performance (accuracy,precision,linearity) of serum sialic acid detection kit using enzymic method was assessed.Two hundred and forty patients were classified into different malignant tumor groups according to their pathological types.Serum SA level of each tumor group was compared with that of normal control group.In tumor groups with statistical difference,benign disease groups were further collected.Receiver operating characteristic (ROC) curve and area under curve (AUC) were used to evaluate the diagnostic value of SA compared with other tumor markers.t test,one-way ANOVA,Mann-Whitney U test were used as statistical methods.Results The reference interval of SA was 479 to 715 mg/L.The detection result of 2 level controls was 584 and 1 482 mg/L respectively,which were both within the acceptable limits.The within-lot and between-lot variations of three level samples were both below 5％.There was a good linear correlation (Y =0.995X-0.177,R2 =0.999) between theoretical value and actual detection result in range of 0-1 052 mg/L.The serum level of SA was (757 ± 177),(514 ± 86) and (597 ± 60) mg/L in gastric cancer group,benign disease control group and normal control group respectively,which had statistically significant difference(F =55.2,P ＜ 0.01).The serum level of SA was(659 ± 127) and (545 ± 66) mg/L in colorectal cancer group and benign disease control group respectively,which had statistically significant difference(F =42.8,P ＜ 0.01).The serum level of SA was (738 ± 157) and (672 ± 161) mg/L in colorectal cancer group and benign disease control group respectively,which did not have statistically significant difference(F =26.3,P ＞ 0.05).The AUC of SA was 0.804,0.724,0.755 in gastric cancer group,colorectal cancer group and lung cancer group respectively,which was higher than that of CEA and CA72-4.In gastric cancer group,the sensitivity of SA was higher than that of CEA (59.5％,24.3％).The AUC of SA was 0.791,0.687,0.790 in gastric cancer,colorectal cancer and lung cancer patients with normal CEA serum level respectively.Conclusions Experimental results show that serum sialic acid detection kit using enzymic method has good performance in the precision and linearity.Sialic acid has some value in the diagnosis of gastric cancer and colorectal cancer and could be a good supplement of CEA in screening of cancer.

Performance evaluation of six homocysteine cycle enzymatic detection systems / 中华检验医学杂志

Objective To evaluate the performance of six homocysteine (Hcy) analysis systems.Methods This is a methodological evaluation study.We analyzed six cycle enzymatic systems,and their correlation and deviation compared with chemiluminescence microparticle immunoassay (CMIA) from Abbott Architect plus i2000 system.Precision,accuracy,anti-interference and analytical measuring range (AMR)were evaluated,according to the CLSI EP5-A2,EP15-A2,EP7-A2,EP6-A,EP9-A2 guidelines.To assess the accuracy,we used the reference material SRM 1955 from National Institute of Standards and Technology (NIST),and EQA samples from CAP and National Center of Clinical Laboratory.Regression analysis was conducted using Passing-Bablok method.Linear regression measurement was performed using Cusum method,with a statistical significance level set at P ＜ 0.05.Correlation analysis was conducted using Pearson coefficient,with P ＜0.05 indicating significant difference.Deviation analysis was performed using Bland-Altman method.Results In the six systems (A1-D2) except A1,the within-run CVs were all ＜ 5％ and the between-run CVs were all ＜ 6.7％ at the Hey concentration range of 10-22 μmol/L.The accuracy validation of NIST SRM 1955 showed that the maximum absolute bias were-3.36,1.43,2.24 μmol/L at low,medium and high levels respectively.Measurement of EQA samples from CAP and National Center of Clinical Laboratory showed that the relative bias were all ＜ TEa (2.5 μmol/L or target value ±20％) in the six systems (A1-D2) except A1.Hb and TBIL interference were significant.The upper limit of AMR for six systems were 47.3,69.76,72.1,73.96,46.23 and 48.98 μmol/L respectively.The measurement results of six systems conelated well with that of CMIA system,with Pearson correlation coefficient (r) ＞ 0.975 (P ＜0.01,n ＞40).Compared with CMIA system,the Bland-Altman results showed that the maximum average absolute deviation was 2.9 μmol/L.Conclusions The cycle enzymatic method used to measure homocysteine has good precision,linear range,and anti-interference ability.But it is noticeable that the results of cycle enzymatic was higher than those of CMIA.Meanwhile,the six systems do not apply to measuring urine samples.

Impacts of different creatinine detection methods on the efficacy of different GFR estimation equations / 中华检验医学杂志

ObjectiveTo investigate the impacts of different serum creatinine detection methods,including Jaffe and enzymatic methods,on the efficacy of different GFR estimation equations in CKD patients in China.MethodsrGFR of 176 patients with CKD were determined by dual plasma sample method 99mTc-diethylenetriamine pentaacetic acid (99mTc-DTPA) plasma clearance rate.Serum creatinine was detected with four kinds of creatinine reagents from different manufacturers.Cockcroft-Gault Equation corrected for body surface area (CG/BSA),simplified Modification of Diet in Renal Disease (MDRD) Study equation,IDMS-traceable MDRD equation,CKD epidemiology collaborative research (CKD-EPI) equation and two Chinese simplified MDRD equation (project group equation 1,2) were applied to calculate estimated GFR (eGFR)respectively.eGFRwerecomparedwithrGFRforthecorrelation, deviation, precisionand30％ accuracy.ResultsThe mean rGFR of 176 patients with CKD,was [ 40.70 ( 19.41 -84.35 ) ] ml · min- 1 ·( 1.73 m2 ) -1.For all GFR estimation equations,there were significant differences in eGFR results between enzymatic method and Jaffe method,when analyzed by the Wilcoxon signed-rank test.eGFR results assessed by two enzymatic creatinine detection systems showed no significant difference,while eGFR results analyzed by two Jaffe detection system were significantly different.The intraclass correlation coefficient (ICC) of eGFR and rGFR ranged from 0.879 to 0.923 by Jaffe method,while from 0.925 to 0.946 by enzymatic creatinine method.ICC and Pearson correlation analysis revealed a significant correlation between eGFR and rGFR,and the correlation was better when using enzymatic method.Bland-Altman plots indicated that large deviation occurred in the high value area of GFR using various equations.However,deviation with the enzymatic creatinine method was smaller than that with the Jaffe method. When rGFR ≥ 60 ml · min- 1 ·(1.73 m2) -1,the 30％ accuracy of eGFR using enzymatic creatinine method for all six equations was between 68.3％ and 90.0％,while it was between 41％ and 75％ when using Jaffe method. The 30％ accuracy of eGFR using enzymatic creatinine method was significantly higher than that using picric acid method for these equations except for the project group equation 1.When rGFR ＜60 ml · min -1 · ( 1.73 m2 ) -1,the 30％accuracy of eGFR using both methods was between 39.7％ -49.1％,40.5％ -52.6％respectively,and the difference of data showed no statistical significance.For the same equation,there was a significant differernce in 30％ accuracy of eGFR between two enzymatic creatinine detection systems,while there was no significant differernce between two Jaffe creatinine detection systems.ConclusionsA significant difference was demonstrated in the same GFR evaluation equation using two different creatinine detection methods (Jaffe method and enzymatic method).The correlation between rGFR and eGFR,the degree of deviation,and accuracy of eGFR results assessed by enzymatic creatinine method were better than those by Jaffe method.The eGFR results assessed by different enzymatic detection systems revealed no significant difference.

Analysis of the results of creatine kinase reference method in ring trial program / 中华检验医学杂志

ObjectiveTo provide a reference for the establishment and appliance of enzyme reference measurement of CK in China by comparing and analyzing the RELA results of CK in IFCC from 2006-2008. Methods The RELA samples of CK were measured according to the reference procedure for the measurement of catalytic activity concentration of CK (37 ℃) ,which had been published by IFCC. The EP5A2 protocol was used for evaluation of the imprecision and ERM was used for verification of the trueness. Results In RELA 2006, the result of sample A was (9. 896 ±0. 112) μkat/L, and the result of sample B was (4.953 ±0. 120) μkat/L. In RELA 2007, the result of sample A was (2.684 ±0.054)μkat/L, and the result of sample B was (8.798 μ0. 101) μkat/L. In RELA 2008, the result of sample A was (10. 523 ±0. 149) μkat/L,and the result of sample B was (10. 551 ±0. 141) μkat/L. The precision of the CK reference method in the year 2006 to 2008 was 0. 92%, 0. 86% and 0. 88% respectively, each of them is less than 1% and the results of ERMs were consistent with the certified value(1. 68 ± 0. 07)μkat/L,which verify the imprecision and accuracy of the reference method. Conclusions All of the results in the continuous three years were in the range of equivalence limits suggested by IFCC. The CK reference method suggested by IFCC has been established and it is getting better.

Comparison of measurements for ALT and AST among four domestic reference laboratories / 中华检验医学杂志

Objective To investigate the intralaboratury and interlabomtory variations of measurements for ALT and AST among four domestic reference laboratories. Methods The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) reference procedures and IFCC procedures without pyridoxal 5-phosphate (PLP) were performed in the reference laboratories. Intralaboratory and interlaboratory CVs were compared with those in 2006 and 2007 IFCC External Quality Assessment Scheme for Reference Laboratories (RELA). Meanwhile, deviations of results for ALT, AST and AST/ALT between two methods were calculated. Results Interlaboratory CVs were generally higher than intralaboratory CVs. Interlaboratory CVs among the 41 laboratories were lower than these in RELA. Results of ALT and AST using method with PLP were higher than those using method without PLP. Difference of AST/ALT ratio between the two methods was significant. Conclusions For reference measurement of the 2 enzymes, interlaboratory CVs of < 3.5 are achievable on frozen serum materials. Measurements on lyophilized materials may have higher CVs. Further studies are needed for the investigation of the differences between results obtained in the absence and presence of PLP.