参加肌酸激酶参考方法国际室间比对计划结果分析

目的 对2006-2008年3年来参加IFCC组织的参考实验室RELA的CK的测定结果 进行比较和分析,为我国CK参考方法 的建立和应用提供借鉴.方法 按照IFCC公布的酶学活性测定(37℃)参考方法 的标准操作程序(SOP)测定CK国际样本,不精密度评价按美国CLSI的EP5-A2进行,准确度评价采用国际有证参考物质(ERM).结果 2006年测定结果 ,样本A CK值为(9.896±0.112)μkat/L,样本B为(4.953±0.120)μkat/L;2007年测定结果 ,样本A为(2.684 ±0.054)μkat/L,样本B为(8.798 ±0.101)μkat/L;2008年测定结果 ,样本A为(10.523±0.149)μkat/L,样本B为(10.551±0.141)μkat/L.2006-2008年CK参考方法 的不精密度分别为0.92%、0.86%、0.88%,均＜1%,ERM测定均值在"靶值±不确定度[(1.68±0.07)μkat/L]"范围内,初步验证了参考方法 的不精密度和准确度.结论 连续3年的CK国际样本测定结果 均在IFCC公布的置信区间(limit of equivalence)±5%范围内,CK的IFCC参考方法 已经建立并且日趋成熟.     

参加肌酸激酶参考方法国际室间比对计划结果分析

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.     

参加肌酸激酶参考方法国际室间比对计划结果分析

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.     

干、湿化学法检测血浆乳酸脱氢酶、肌酸激酶、肌酸激酶同功酶的比较

干化学检测心肌酶具有快速、简便的特点,在急诊医学有较好的应用前景。本文分析了干、湿化学法检测心肌酶的差别。     

探讨不同检测系统血凝仪测定结果的比对

目的探讨不同检测系统血凝仪之间的可比性,以达到质量控制的效果。方法分别用STA compact和CA-1500血凝仪测定质控、100份比对样本(浓度覆盖生物参考区间),然后对测定结果进行分析、比较,以美国临床医学检验部门修正法规(CLIA'88)允许总误差的1/2及相关性比较(r0.975)为判断标准,观察2台仪器的可比性、相关性。结果 STA compact和CA-1500血凝仪在测定无黄疸和脂血的标本时国际标准化比值(INR)、低值纤维蛋白原(Fbg)结果一致,相对偏差在允许范围内,相关性较好(r0.975),而测定活化部分凝血活酶时间(APTT)时相关性尚可,但相对偏差不在允许范围内。在测定黄疸或(和)脂血的标本时INR、APTT、Fbg时结果均不一致,相对偏差不在允许范围内,相关性不好(r0.975)。结论通过比对可以反应不同检测系统血凝仪结果之间的可比性、相关性及差异。     

CHOL TGL在不同生化分析仪的测定结果比对

随着检验医学技术的不断发展,越来越多的临床实验室配备多台生化分析仪,同一项目在不同生化仪上检测已很普遍,为确保实验室内检测结果的一致性和可比性,作者参照美国国家临床实验室标准化委员会(NCCLS)EP15A 文件或EP9-A2 文件,要求进行实验室内不同检测系统相同检验项目的比对实验.     

中国四家参考实验室间ALT和AST的测定结果比对分析

目的 调查我国4家参考实验室应用国际临床化学联合会(IFCC)推荐加和不加磷酸吡哆醛参考方法测定ALT和AST的室内和室间变异,为设定合适的室内和室间变异的范围提供依据.方法 建立加和不加磷酸毗哆醛的IFCC方法,用均一性良好的5个浓度冰冻混合人血清作为比对材料,观察各实验室测量比对样本的室内和室间变异,并与2006年和2007年参考实验室外部质量评价计划(RALE)的结果做比较.同时分析加与不加磷酸吡哆醛时AST、ALT测定值及AST/ALT比值的差异.结果 本次比对的室间变异大于室内变异,仅个别实验室在个别结果出现室内变异大于室间变异的情况.室内变异不大于RELA比对室内变异的变化,室间变异亦明显小于后者.加磷酸吡哆醛法的ALT和AST测量值均比未加法高,两种方法得到的AST/ALT比值具有显著性差异.结论 建议酶学参考实验室ALT、AST测定室内变异分别小于2.72%、2.58%;使用冰冻血清作比对材料时,二者的室间变异小于3.5%;冰冻干燥品作比对材料时,二者的室间变异小于4.5%,应观察不同个体样本加和不加磷酸吡哆醛转氨酶测定值及其比值的变化在疾病诊断与预后评估中的临床意义.     

六种临床诊断酶学测定参考方法的应用及国际比对结果分析

目的 应用国际临床化学联合会(IFCC)公布的参考方法对血清丙氨酸氨基转移酶(ALT)、(天)门冬氨酸氨基转移酶(AST)、乳酸脱氢酶(LDH)、肌酸激酶(CK)、γ-谷氨酰基转移酶(GGT)及淀粉酶(AMY)6个酶进行测定,并通过参加参考实验室国际比对计划评估参考方法的准确性.方法 按照IFCC有关酶学活性测定(37℃)参考方法的标准操作程序(SOP),分别使用PE和Agilent的两套测定系统进行6个酶的测定.通过测定质控血清监测两套测定系统的稳定状态、有证参考物(CRM)并参加酶学国际比对(ring trial),验证参考方法的准确性.结果 两套系统测定室内质控血清的测值稳定,6种酶天间测定变异系数为0.5%～1.9%;测定结果一致,两者结果偏移小于2.1%;CRM测定结果在允许的范围内,初步验证了参考方法的准确性;高低两个浓度样本,两个独立系统的国际比对结果中有4个酶(ALT、AST、GGT、AMY)的测定值位于所有参考实验室测定的(x)±s范围内,LDH与CK测值位于(x)±2s之间;用稳健统计学方法评价,除了LDH的样本A测值属于离散值以外,其他5个酶ALT、AST、CK、GGT、AMY及LDH样本B的比对结果未发现离群.结论 应用IFCC参考方法采用两套测定系统对6个酶进行的测定结果稳定、准确,具有等效性.     

乳酸脱氢酶在干式和湿式化学检测系统测定结果的可比性分析

目的探讨两个不同检验系统间乳酸脱氢酶(LDH)测定结果是否具有可比性,建立具有可比性的参考区间,为临床诊断治疗提供可靠的实验数据。方法参考美国临床实验标准化委员会(NCCLS)的标准,以罗氏PD模块全自动生化分析仪、原装试剂、C.f.a.s校准品和原装质控品组成的检测系统为比较方法 ;以强生350型全自动干式生化分析仪、原装试剂及原装配套校准品、质控品组成检测系统为实验方法。按两个检测系统相兼并的检测范围,分批次制备浓度有高有低新鲜血清组成合理分布的样本对LDH进行检测,计算实验方法 (Y)和比较方法 (X)之间的偏倚,以CLIA88规定的室间质量评价允许误差范围的1/2为标准,判断两个检测系统的可比性。结果 LDH测定结果在两个检测系统间有显著性差异,但呈高度相关(r=0.9905)。结论两个以上检验系统进行LDH检测时,应进行方法比对和偏倚评估,建立相对应具有可比性的参考区间,以保证检验结果的可比性。     

7家三级甲等医院HBV标志物测定结果可比性的调查

为了减少重复检查,降低患者就诊费用,卫生主管部门推出了医疗机构间医学检验结果互认的举措。河北省实验室质量管理与控制中心对省属7家三级甲等医院实验室HBV标志物的检验结果进行了比对,结果如下。[第一段]     

Creatine kinase and lactate dehydrogenase isoenzymes in stage D prostatic carcinoma

Serum creatine kinase (CK) and lactate dehydrogenase (LD) isoenzymes were determined electrophoretically, along with various other biochemical markers of malignancy, in 19 patients with metastatic carcinoma of the prostate. Mitochondrial CK appeared in 15 patients, the CK-BB isoenzyme in 6. As a result, CK activity not inhibited by anti-M-subunit antibodies, CK non-M, was above the reference value in altogether 17 patients. There was a cathodic shift among the LD isoenzymes, significantly more prominent with increasing total LD, and a positive correlation between elevations of CK non-M and LD-5, suggesting a relation to tumour burden for both. An LD 'flip' (LD-1 greater than LD-2) was present in 10/15 patients. The frequency of CK non-M elevations was similar to--but not quantitatively correlated with--elevations of prostatic acid phosphatase and alkaline phosphatase. Thus, changes in CK and LD patterns are frequent in patients with prostatic cancer and must be taken into consideration when acute cardiac symptoms are evaluated in such patients.     

Creatine kinase and lactate dehydrogenase isoenzymes in serum and tissues of patients with stomach adenocarcinoma

Total activities of creatine kinase (EC 2.7.3.2; CK) and lactate dehydrogenase (EC 1.1.1.27; LD) and their isoenzymes were estimated in serum and tissue samples from patients with stomach adenocarcinomas who were to undergo gastric resection. Total CK activity (U/g protein) appeared to be markedly decreased in neoplastic stomach tissue. CK-BB was the predominant isoenzyme in both neoplastic and normal stomach tissues; however, the CK-BB/total CK ratio was increased in adenocarcinoma tissue. Macro CK type 1 was found in two neoplastic tissues and macro CK type 2 in 11. LD4 and LD5 isoenzymes were predominant in gastric tissues, but LD5 and the LD5/LD1 ratio were higher in adenocarcinoma tissue. At 24 h before surgery, CK-BB was demonstrated in sera of all patients and CK-MB in 69%. The CK-BB probably originated from neoplastic stomach tissue, which contains high CK activity, with BB isoenzyme predominating. After gastrectomy, CK and LD isoenzymes in sera were markedly increased by 24 h postsurgery. These alterations were attributed to release from damaged tissue during gastric resection.     

Creatine kinase and lactate dehydrogenase isoenzymes in serum of patients suffering burns, blunt trauma, or myocardial infarction

Medical records of 53 burn and trauma patients were reviewed to assess the possibility of myocardial damage. Except for electrophoretically detectable creatine kinase MB isoenzyme, none showed evidence of myocardial injury. Lactate dehydrogenase isoenzyme tests, electrocardiograms, myocardial pyrophosphate scans, clinical course, and results of (two) autopsies were all negative for myocardial necrosis or ischemia. Types of patient, number, mean peak value (U/L) for serum creatine kinase, and ranges of percentage MB isoenzyme were as follows. Burns from direct electrical contact: 28, 16 600, 0-29; electrical flash or other thermal burns: 10, 4340, 0-22; blunt trauma (mostly from automobile accidents): 15, 3430, 0-18; myocardial infarction: 57, 1520, 4-46. Evidently creatine kinase MB isoenzyme is nonspecific in burn and trauma patients and should not be the only test result used to assess myocardial involvement.     

Diphosphoglycerate mutase assay: the effect of pyruvate, lactate dehydrogenase and thyroid hormone on the assay

An improved assay for 1,3-diphospho-d-glycerate: 3-phospho-d-glycerate phosphotransferase (EC 2.7.5.4) is obtained by adding sodium pyruvate and lactate dehydrogenase to the assay medium. Excess lactate dehydrogenase is necessary because the reaction is inhibited as the pyruvate concentration increases. The rate of 2,3-diphosphoglycerate synthesis in this system was not altered by addition of either thyroxin or 3,5,3-triiodo-l-thyronine.     

Association between sedentary behavior and normal-range lactate dehydrogenase activity

Objectives: Recent research demonstrates that lactate dehydrogenase (LDH) activity within the normal range may serve as a mediator in the (positive) relationship between physical activity and cardiovascular disease risk. Emerging work supports deleterious associations between sedentary behavior and health, independent of physical activity. Thus, this study evaluated if sedentary behavior was associated with normal-range LDH activity, independent of physical activity.

Methods: Data from the 2003–2006 NHANES were used (N = 2,087 adults; 40–79 yrs). LDH activity levels were estimated from a blood sample using LX20 and LDH reagent; participants were included if they had LDH activity levels within the normal range (105–333 IU/L). Physical activity and sedentary behavior were assessed via accelerometry.

Results: Sedentary behavior was inversely associated with normal-range LDH activity when physical activity was excluded from the model (OR = 0.89; 95% CI: 0.83–0.97, P = 0.009 for LDH activity quartile 4 vs. 1). However, sedentary behavior was no longer associated with normal-range LDH activity after controlling for physical activity and other covariates (OR = 1.00, P = 0.49 for LDH activity quartile 2 vs. 1; OR = 1.00, P = 0.72 for LDH quartile 3 vs. 1; and OR = 0.99, P = 0.36 for LDH quartile 4 vs. 1).

Conclusion: Unlike physical activity, sedentary behavior is not independently associated with normal-range LDH activity.     

Effect of lactate dehydrogenase isoenzymes on the coupled enzymatic assay for alanine aminotransferase activity.

We show an example of the importance of specifying the form of isoenzyme and source of indicator enzymes to be used in coupled enzymatic assays. When we compared H-4 (pig heart) and M-4 (rabbit muscle) isoenzymes of lactate dehydrogenase for their suitability as indicator enzymes in the assay for alanine aminotransferase activity, we found that about fourfold as much M-4 as H-4 was required in terms of lactate dehydrogenase activity to reflect accurately equivalent amounts of alanine aminotransferase activity. Moreover, the substrate specificities of the two isoenzymes differed quantitatively.     

Mechanism of differential inhibition of lactate dehydrogenase isoenzymes in the BMC LD-1 assay

The mechanism of inhibition of lactate dehydrogenase (LD) isoenzymes by guanidinium thiocyanate (GSCN) used in the LD-1 assay developed by Boehringer Mannheim Corporation (BMC) was investigated. Michaelis-Menten inhibition kinetics for the individual isoenzymes revealed that GSCN competitively inhibited LD-1 in the presence of lactate and NAD+, but is a noncompetitive inhibitor of LD-5. LD-2 and LD-3 exhibited mixed inhibition kinetics. The inhibition constants were two- to threefold smaller for LD-5 than for LD-1. Time-dependent studies also showed that the isoenzymes underwent a different rate of inactivation by GSCN. LD-5, LD-3, and LD-2 were rapidly inactivated within 1 min under the BMC assay conditions, whereas LD-1 lost only about 20% of activity after 10 min. The presence of lactate further protects LD-1, but not other isoenzymes. Under this condition, LD-1 was not inactivated during the initial 6 min of reaction. Separate experiments demonstrated that both guanidinium and thiocyanate ions are responsible for the inactivation process that was found to be irreversible. We speculate that GSCN selectively denatures the M subunit of LD. The H subunit is less susceptible to denaturation and is further stabilized by lactate.     

A study on the effects of severe repetitive exercise on serum myoglobin, creatine kinase, transaminases and lactate dehydrogenase

Two groups of young men taking part in a 24-day training course involving increasingly severe exercise were studied. Serum myoglobin, creatine kinase, creatine kinase-MB, transaminases, lactate dehydrogenase, urea, creatinine, calcium and uric acid were estimated at intervals. During the first few days, increases in myoglobin and muscle enzymes correlated with the severity of the preceding exercise. Increases in myoglobin and muscle enzymes after the final most severe exercising were less than with the initial exercising, demonstrating the effect of physical training. The changes in myoglobin and the muscle enzymes correlated closely. Elevated myoglobin levels persisted for over 24 hours. There was no consistent correlation between changes in myoglobin and uric acid, both of which have been considered responsible for the renal failure which may occur with rhabdomyolysis.