Laboratory diagnosis of patients with acute chest pain.

The enzyme activities of creatine kinase (CK), its isoenzyme MB (CK-MB) and of lactate dehydrogenase isoenzyme 1 (LD-1) have been used for years in diagnosing patients with chest pain in order to differentiate patients with acute myocardial infarction (AMI) from non-AMI patients. These methods are easy to perform as automated analyses, but they are not specific for cardiac muscle damage. During the early 90's the situation changed. First creatine kinase MB mass (CK-MB mass) replaced the measurement of CK-MB activity. Subsequently cardiac-specific proteins troponin T (cTnT) and troponin I (cTnI) appeared on the scene, displacing LD-1 analysis. However, troponin concentrations in blood increase only from four to six hours after onset of chest pain. Therefore a rapid marker such as myoglobin, fatty acid binding protein or glycogen phosphorylase BB could be used in early diagnosis of AMI. On the other hand, CK-MB isoforms alone may also be useful in rapid diagnosis of cardiac muscle damage. Myoglobin, CK-MB mass, cTnT and cTnI are nowadays widely used in diagnosing patients with acute chest pain. Myoglobin is not cardiac-specific and therefore requires supplementation with some other analyses such as troponins to support the myoglobin value. Troponins are very highly cardiac-specific. Only the sera of some patients with severe renal failure, which requires hemodialysis, have elevated cTnT and/or cTnI without there being any evidence of cardiac damage. On the other hand, the latest studies have shown that elevated troponin levels in sera of hemodialysis patients point to an increased risk of future cardiac events in a similar manner to the elevated troponin values in sera of patients with unstable angina pectoris. In addition, the bedside tests for cTnT and cTnI alone or together with myoglobin and CK-MB mass can be used instead of quantitative analyses in the diagnosis of patients with chest pain. These rapid tests are easy to perform and they do not require expensive instrumentation. For routine clinical laboratory practice we suggest that in diagnosis of patients with chest pain, myoglobin and CK-MB mass measurements should be performed whenever they are requested (24 h/day) and cTnT or cTnI on admission to the hospital and then 4-6 and 12 hours later.     

血清肌钙蛋白Ⅰ对急性心肌梗死早期诊断的临床价值

目的观察急性心肌梗死(AMI)患者入院前后血清肌钙蛋白I(cTnI),心肌肌酸激酶同工酶MB(CK-MB)测定值的变化。探讨cTnI对早期诊断AMI的价值。方法对50例AMI患者和50例健康人血清进行cTnI和CK—MB的检测。结果 AMI后3h内cTnI阳性检出率94．0％,明显高于CK-MB24．0％,AM15d后cTnI阳性84．0％,而CK-MB仅为6．0％。结论血清cTnI能早期确切诊断AMI,具有较宽的诊断窗,是急性心肌梗死早期诊断较敏感和特异的血清标志物。     

肌钙蛋白Ⅰ与CK-MB联合检测对急性心肌梗死的诊断价值

目的探讨肌钙蛋白I(cTnI)与CK-MB联合检测对急性心肌梗死(AM I)的临床诊断价值。方法采用罗氏电发光2010自动生化分析仪和日立7180生化分析仪,测定62例AM I患者、50例健康体检者血清的cTnI、肌酸激酶(CK)和CK-MB,并对结果进行统计学分析。结果AM I组血清cTnI、CK和CK-MB高于正常对照组(P<0.01)。cTnI与CK-MB联合检测阳性率为96.7%,高于前三者,且动态检测对早期AM I敏感性更高、阳性持续时间更长。结论肌钙蛋白I与CK-MB联合检测能提高早期急性心肌梗死的检出率,具有更宽的诊断时间窗。     

Time-dependent diagnostic performance of a rapid troponin T version 2 bedside test in patients with acute coronary syndromes

In a prospective trial, the diagnostic performance of the second version of the troponin T rapid assay (Trop T; cutoff 0.2 microg/L) was compared with the quantitative cardiac-specific troponin T assay (cTnT ELISA; cutoff 0.1 microg/L) and other established cardiac markers such as CK, CK-MB activity, CK-MB mass and myoglobin. Additionally, a 30-day follow-up was performed to determine the suitability of the Trop T assay and the reference markers for short-term risk stratification. Two-hundred-and-eighty-six consecutive patients with chest pain and suspected acute myocardial infarction (AMI) were enrolled in two CCU departments. Serial blood specimens were taken at admission and at 3, 6, 12, 24, 48, 72 and 96 h after admission. According to the biochemical criterion CK-MB mass, the patients were classified as having AMI in 154 patients (54%), unstable angina (UAP) in 72 patients (27%) and no evidence for acute cardiac ischemia in 55 patients (19%). Analytical method comparison of Trop T with cTnT ELISA (cutoff 0.1 microg/L) showed a good agreement, Trop T yielded only 4% false-negative and 3% false-positive results. The diagnostic performance of Trop T for the detection of AMI was only slightly inferior compared to cTnT ELISA. Beyond 12 h after admission, Trop T and cTnT ELISA maintained a sensitivity close to 100%, whereas the sensitivity of the other cardiac markers decreased sharply. The diagnostic sensitivity of Trop T for the detection of minor myocardial damage in UAP patients was the same as for cTnT ELISA. Death within 30 days' follow-up occurred only in AMI patients with a positive Trop T test result within the first 6 h after admission. The admission Trop T and cTnT ELISA were the only significant biochemical predictors of major cardiac events. In conclusion, these data show that Trop T has similar diagnostic sensitivity as cTnT ELISA and is a useful tool to confirm acute or subacute myocardial infarction. Trop T is an excellent marker in detecting minor myocardial damage in UAP patients and is suitable for short-term risk stratification.     

Early Diagnostic Efficiency of Cardiac Troponin I and Troponin T for Acute Myocardial Infarction

Objective : To compare the early diagnostic efficiency of the cardiac troponin I (cTn-I) level with that of the cardiac troponin T (cTn-T) level, as well as the creatine kinase (CK), CK-MB, and myoglobin levels, for acute myocardial infarction (AMI) in patients without an initially diagnostic ECG presenting to the ED within 24 hours of the onset of their symptoms. Methods : A prospective, observational, cohort study was performed involving chest pain patients admitted to a large urban community hospital. Participants were consecutive consenting ED chest pain patients ≥30 years of age. Exclusions included duration of symptoms >24 hours, inability to complete data collection, receipt of CPR, and ST-segment elevation on the initial ECG. Measurements included levels of cTn-I, cTn-T, CK, CK-MB, and myoglobin at the time of presentation and 1, 2, 6, and 12–24 hours after presentation as well as presenting ECG and clinical follow-up. Confirmation of the diagnosis of AMI was based on World Health Organization criteria. Results : Of the 177 patients included in the study, 27 (15%) were diagnosed as having AMIs. The sensitivities of all 5 biochemical markers for AMI were poor at the time of ED presentation (3.7–33.3%) but rose significantly over the study period. The sensitivity of cTn-T was significantly better than that of cTn-I over the initial 2 hours, but both markers' sensitivities were low (<60%) during this time frame. The cTn-I was significantly more specific for AMI than was the cTn-T, but not significantly better than CK-MB or myoglobin. Likelihood ratio analysis showed that the biochemical markers with the highest positive likelihood ratios for AMI during the first 2 hours following ED presentation were myoglobin and CK-MB. From 6 through 24 hours, the positive likelihood ratios for cTn-I, CK-MB, and myoglobin were superior to those of CK and cTn-T. Conclusions : cTn-I, CK-MB, and myoglobin are significantly more specific for AMI than are CK and cTn-T. Myoglobin is the biochemical marker having the highest combination of sensitivity, specificity, and negative predictive value for AMI within 2 hours of ED presentation. Neither cTn-I nor cTn-T offers significant advantages over myoglobin and CK-MB in the early (≤2 hours) initial screening for AMI. The cardiac troponins are of benefit in identifying AMI ≤6 hours after presentation.     

Analytical and clinical evaluation of creatine kinase MB mass assay by IMx: comparison with MB isoenzyme activity and serum myoglobin for early diagnosis of myocardial infarction.

We analytically and clinically evaluated Abbott's IMx assay for creatine kinase (CK) isoenzyme MB (CK-MB) in serum. Over a 1-year period, the method was more specific but less precise than catalytic isoenzyme measurements by electrophoresis or immunoinhibition. Sera from different individuals without electrophoretic evidence of CK-MB but containing macro CK type 1 (n = 20), mitochondrial CK (n = 5), or CK-BB (n = 5) were scored as CK-MB negative by the IMx. Likewise, CK-MB-negative by the sera remained so after addition of purified human CK-MM (< or = 7600 U/L) or CK-BB (< or = 8100 U/L). For 39 patients admitted for suspicion of uncomplicated acute myocardial infarction (precordial pain for < or = 4 h), the diagnostic performance of the IMx CK-MB assay on admission and 4 h later was superior to that of total CK activity and compared well with that of CK-MB activity measured by electrophoresis or immunoinhibition. An admission, myoglobin showed a higher diagnostic sensitivity, specificity, and predictive value than did CK-MB and was the most informative test. Diagnostic performance on admission and 4 h later was further improved by considering positivity for myoglobin and for CK-MB by IMx and for the change in each over the first 4 h of hospitalization as criteria. Twelve hours after admission, diagnostic performance was further improved for all CK and CK-MB methods but began to decline for myoglobin.     

The sensitivity of cardiac markers: an evidence-based approach.

The aim of this study was to determine whether, using an evidence-based approach, the results of the papers found in the literature are valid and sufficiently scientifically rigorous to be used to definitely address the problem of cardiac marker sensitivity in detection of acute myocardial infarction. In particular, the diagnostic sensitivities of myoglobin, creatine kinase (CK)-MB isoenzyme, determined as mass concentration, CK-MB isoforms, and of the two cardiac troponins, troponin I and troponin T, were reviewed using a priori formulated inclusion/exclusion criteria for judging the eligibility of studies to be included in the analysis. A clear final message derived from this systematic analysis is the unacceptably poor diagnostic sensitivity of all evaluated markers at patient admission, with substantial failure rate to rule out myocardial infarction at this time. Myoglobin is at present the most sensitive of the markers studied for excluding early AMI with an optimum timing of sampling at patient presentation and approximately 4 h later. However, this marker cannot be used by itself as a proportion of patients admitted to the hospital with a late infarction could be missed. The early rate of rise of CK-MB mass and troponin T is similar. Maximum sensitivity of these two parameters is achieved by the analysis of a second sample 6 to 12 h after admission. Additional larger studies are needed to address the question which troponin shows earlier release after myocardial damage, and to clarify the role of CK-MB isoforms as a possible early marker of myocardial infarction.     

荧光免疫微流定量检测急性心肌梗死三联的性能及诊断效果评价

目的评价荧光免疫微流定量检测急性心肌梗死(AMI)三联(简称心梗三联)[肌红蛋白(Myo)、肌酸激酶同工酶(CK-MB)和肌钙蛋白I(cTnI)]的性能及在AMI中的诊断效果。方法选择2018年11月至2019年5月该院诊治的疑似AMI患者53例为研究对象,其中经冠状动脉造影确诊的AMI(AMI组)33例,冠心病等其他疾病(非AMI组)20例。选取同期健康体检者30例为对照组。采用esLabs hyper i300全自动干式荧光免疫分析仪、微流控定量试剂盒(免疫荧光法)检测心梗三联,分析心梗三联对AMI的诊断性能及验证仪器精密度。结果3组Myo、CK-MB和cTnI水平比较,差异均有统计学意义(P<0.05)。ROC曲线分析结果显示,cTnI诊断AMI的AUC值大于Myo、CK-MB及Myo+CK-MB+cTnI串联、并联(P<0.05)。Myo+CK-MB+cTnI并联诊断AMI的灵敏度(97.0%)高于Myo、CK-MB及Myo+CK-MB+cTnI串联(P<0.05)。Myo+CK-MB+cTnI串联诊断AMI的特异度(100.0%)高于Myo、CK-MB及Myo+CK-MB+cTnI并联(P<0.05)。荧光免疫微流定量检测Myo、CK-MB、cTnI的批间、批内精密度均不超过10%,符合判定标准。结论荧光免疫微流定量检测心梗三联性能良好,诊断效果佳,能基本满足AMI的辅助诊断应用,可用于临床实验室。     

心肌标志物检测在早期诊断急性心肌梗死中的价值

目的探讨胶体金免疫层析法检测血清肌钙蛋白Ⅰ、肌酸激酶同工酶（CK-MB）、肌红蛋白在急性心肌梗死（AMI）患者早期不同时间段的诊断价值。方法收集该院2011年1月至2012年12月收治的89例AMI病例,根据发病时间分为两组,2～〈6h组42例,6～12h组为47例,非心肌梗死对照组70例。采用血清肌钙蛋白Ⅰ、CK-MB、肌红蛋白三合一诊断试剂对选取的病例进行测定。结果AMI患者肌钙蛋白Ⅰ、CK-MB、肌红蛋白的阳性率均高于对照组（P〈0．05）,在2～〈6h时间段内三者的敏感度分别为35．7％、64．3％、52．4％,均低于6～12h时间段的48．9％、85．1％、76．6％,结果差异有统计学意义（P〈0．05）。CK-MB用于诊断的敏感度在两个时间段内分别为：64．3％、85．1％,较肌钙蛋白I（35．7％、48．9％）、肌红蛋白（52．4％、76．6％）高,差异有统计学意义（P〈0．05）,而肌红蛋白敏感度较肌钙蛋白Ⅰ高（P〈0．05）。将三者联合测定时,阳性率高于单独测定时的阳性率,2～6h组阳性率为69．0％,6～12h组阳性率为89．4％。结论在AMI早期,肌钙蛋白Ⅰ、CK-MB、肌红蛋白单独测定阳性率较低,不能满足临床需要,而采用胶体金法心肌三合一诊断试剂盒,对肌钙蛋白Ⅰ、CKMB、肌红蛋白进行联合测定能提高AM1的早期诊断阳性率,以便为临床提供可靠的实验信息,及时采取有效的治疗措施,从而降低患者的病死率。     

AMI患者发病后血浆UCA1、CK-MB、cTnI变化及其诊断价值分析

目的分析急性心肌梗死(AMI)患者发病后血浆尿路上皮癌相关1(UCA1)、肌酸激酶同工酶MB(CK-MB)、肌钙蛋白I(cTnI)变化及其诊断价值。方法选取2016年7月至2017年6月本院收治的80例AMI患者及30例健康志愿者为研究对象,分别纳入AMI组、对照组,采用实时荧光定量聚合酶链反应法(qPCR)检测UCA1,比较两组入院后0~2、2~6、6~12、12~24、24~48、48~72、72~96 h血浆UCA1及CK-MB、cTnI水平,分析AMI组中合并不同基础疾病(高血压、糖尿病、高脂血症)患者UCA1、CK-MB、cTnI水平差异。结果与对照组比较,AMI组UCA1整体表达水平下调,且AMI组入院后0~48 h UCA1低于对照组(P<0.05),AMI组中UCA1在6~12 h降至最低(P<0.05),后升高(P<0.05),至入院后48~72 h、72~96 h与对照组比较差异无统计学意义(P>0.05);AMI组入院后2~48 h CK-MB、cTnI水平高于对照组(P<0.05),CK-MB在6~12 h达峰值,cTnI在12~24 h达峰值(P<0.05);AMI组中单纯AMI、合并高血压、合并糖尿病、合并高脂血症、合并2种及以上患者UCA1、CK-MB、cTnI表达水平分别两两比较差异无统计学意义(P>0.05);入院后6~12 h UCA1诊断AMI的灵敏度、特异度、准确度、ROC曲线下面积分别为85.42%、83.14%、86.11%、0.954,均较CK-MB、cTnI高。结论AMI患者发病后血浆UCA1表达水平可作为其潜在诊断标志物及治疗靶点,尤其在入院后6~12 h的UCA1有较高监测价值。     

Rapid risk stratification in suspected acute coronary syndrome using serial multiple cardiac biomarkers: A pilot study

Objective: To determine the feasibility of using a biomarker panel of myoglobin, creatinine kinase MB (CK‐MB) and cardiac troponin I (cTnI) to identify patients with suspected acute coronary syndrome (ACS) who are suitable for discharge within 2 h. Methods: We took blood at presentation and at 2 h from patients with suspected ACS and non‐diagnostic electrocardiogram who were admitted to the ED short stay ward for serial electrocardiogram and troponin testing. We used a point‐of‐care device that gives rapid estimation of myoglobin, CK‐MB and cTnI (Triage cardiac panel). These results were compared with the results of our standard hospital cardiac troponin T assay. Patients were followed up by telephone at 30 days. Results: The study group comprised 100 patients (61 men) with mean age of 58 years. Six had a troponin‐positive ACS during their ED stay. One additional patient died of a myocardial infarction within the follow‐up period. The Triage panel at 2 h after presentation predicted 12‐h cardiac troponin T elevation (sensitivity 100%, negative predictive value 99%) and 30‐day events (sensitivity 86%, negative predictive value 97%). The majority of patients were ultimately suitable for discharge. Conclusion: Serial myoglobin, CK‐MB and cTnI have the potential to identify patients who are suitable for early discharge and outpatient work‐up. A large multicentre study is required.     

Diagnosis and risk stratification of patients with anginal pain and non-diagnostic electrocardiograms

Patients with acute chest pain suggestive of myocardial ischaemia, and normal or non-diagnostic electrocardiograms, form a difficult subgroup for diagnosis and early risk stratification. We prospectively evaluated the role of troponin T (cTnT), troponin I (cTnI), CKMB mass and myoglobin, in the diagnosis and risk stratification of 214 patients with acute chest pain of < or = 24 h and non-diagnostic or normal ECGs admitted directly to the Cardiac Unit of the Royal Victoria Hospital Belfast from the Mobile Coronary Care Unit or the Accident/Emergency Department. This was a single-centre prospective study, and follow-up (3 months) was complete for all patients. Blood was assessed for quantitative cTnT, cTnI, CKMB mass and myoglobin, and qualitative cTnT on admission and at 12 h. Diagnosis of index event and incidence of new cardiac events (death, non-fatal myocardial infarction, revascularization, or readmission for unstable angina) over 3 months were assessed. Based on standard criteria, myocardial infarction occurred in 37/214 (17%), and unstable angina in 72/214 (34%). At 12 h from admission, cardiac troponins had higher sensitivity for the diagnosis of acute coronary syndromes (myocardial infarction and unstable angina) than conventional markers (cTnI 48%, cTnT 38%, CKMB mass 30% or myoglobin 27%). At 3 months, a new cardiac event had occurred in 42/214 (20%). Significantly higher event rates occurred when any of the biochemical markers was elevated, but the statistical significance was highest for patients with elevated cTnI (p < 0.0001). Whilst gender, history of ischaemic heart disease (IHD), stress test response, cTnT, cTnI, CKMB mass and myoglobin were univariate predictors, cTnI at 12 h and stress test response were the only two independent significant predictors for a subsequent cardiac event at 3 months. Raised cTnI at 12 h after admission had the highest sensitivity for the diagnosis of acute coronary syndromes, and was independently associated with a 2-3 times increased risk of future cardiac events within 3 months among patients with acute chest pain suggestive of myocardial ischaemia but with normal or non-diagnostic ECGs.     

急性心肌梗死早期患者3种血清测定及意义

目的探讨血清肌酸激酶同工酶-MB(CK-MB)、肌红蛋白(Myo)和人心肌肌钙蛋白I(CTnI)检测在急性心肌梗死(AMI)早期诊断中的意义。方法以40例健康体检者作对照,检测85例高度疑为AMI的患者在发病6 h内检测3个血清指标水平。比较其对AMI诊断的性能,以进行优化组合检测。结果 AMI患者在发病6 h内,CK-MB、Myo和CTnI的敏感性分别为82.35%、100.00%和92.64%;特异性分别为94.74%、89.47%和100.00%;单项比较:敏感度和阴性预期值以Myo最高,特异度、阳性预期值和可靠性则以CTnI最佳;并联组合比较:敏感度、特异度、阳性预期值和阴性预期值均以CTnI与Myo最理想;可靠性则以CTnI与CK-MB联合最好;串联组合比较:5项指标均以CTnI与Myo串联检测为最佳。结论血清CTnI在AMI早期诊断中具有良好的灵敏度、特异性和可靠性。CTnI和Myo联合检测可提高对AMI早期诊断的性能。     

Improved early risk stratification and diagnosis of myocardial infarction, using a novel troponin I assay concept

BACKGROUND: We evaluated the clinical performance of a novel cardiac troponin I (cTnI) assay specifically designed to improve the very early risk stratification in acute coronary syndromes. SUBJECTS AND METHODS: Serum and plasma samples (taken 0, 6-12 h and 24 h after admission) from 531 patients with suspected acute coronary syndrome were studied using a novel investigational cTnI assay, reference cTnI assay and myoglobin. The lowest cTnI concentration giving a total assay imprecision of 10% was used as the positive myocardial infarction (MI) cut-off value. RESULTS: At the time of admission, the investigational assay was positive in 27.9% of the patients, the reference cTnI assay was positive in only 17.5% (P < 0.001) and myoglobin in 24.1% (P = 0.067). Receiver operating characteristic (ROC) curve analysis for the detection of myocardial injury on admission gave area-under-curve (AUC) values of 0.937, 0.775 and 0.762, respectively (P < 0.001). Of those MI patients who presented within 3 h of symptom onset, 50.0% were identified by the investigational assay at the time of presentation, compared with 44.2% by myoglobin (P = 0.791) but only 11.5% by the reference assay (P < 0.001). CONCLUSIONS: The novel cTnI assay considerably improves the performance of cTnI as an early rule-in biomarker for MI.     

Evaluation of a new automated system for the determination of ck-mb isoforms

We evaluated a new analyzer (Cardio REP) specifically designed for cardiac CK-MB isoenzyme and isoforms activity, with a performance time of 24 minutes. Ten AMI patients, with times elapsed between the onset of chest pain and admission to hospital ranging from 30 minutes to 4 hours, were monitored every 3–4 hours until the 16th hour of hospitalization. In each serum sample, in addition to total CK-MB and CK-MB isoforms measured by the Cardio REP analyzer, we also assayed total CK activity, CK-MB activity by immunoinhibition method, CK-MB mass concentration, CK-MB isoforms by REP method, troponin T, and myoglobin. The precision study demonstrated acceptable within assay and between assay CVs% for total CK-MB (8.1 and 10.4), MB₁ (9.1 and 14.2), and MB₂ (9.1 and 8.2) isoforms. The method was found to be linear up to 371 U/L for MB₂ isoform fraction and up to 516 U/L for total CK-MB. Results for CK-MB obtained with the Cardio REP correlated well with those for CK-MB activity obtained with the immunoinhibition method (r = 0.869) and those of CK-MB mass concentration (r = 0.923). The sensitivity of the Cardio REP CK isoforms method was found to be greater than that of the REP CK isoforms method. Time to first increased value of MB₂/MB₁ ratio and MB₂ isoform was earlier in comparison to that for CK-MB mass concentrations and similar to that for myoglobin, a marker that, however, lacks specificity. The diagnostic efficiency of CK-MB isoforms and the availability of a real-time, fully automated method for their measurement suggest the utilization of this biochemical marker in emergency for the early diagnosis of AMI.     

快速检测心肌标志物诊断急性心肌梗死的价值

目的探讨快速联合检测肌红蛋白(Myo)、心肌肌钙蛋白I(CTnI)、肌酸激酶同工酶MB(CK-MB)诊断急性心肌梗死(AMI)的价值。方法采用免疫金标法对疑似AMI患者于发病后不同时间进行心肌标志物(Myo、CTnI、CK-MB)的快速检测,并与生化指标心肌酶谱结果进行对照。结果心肌标志物诊断AMI的敏感度为95.8%,特异度为95.1%,均高于心肌酶谱的敏感度(69.9%)和特异度(70.7%)。联合检测Myo、CK-MB、CTnI在保证敏感度的前提下提高了方法的特异度。结论心肌标志物可以取代心肌酶谱对心肌损伤做出诊断,即时检验(POCT)检测系统对于AMI的及时诊断有重大意义。     

心脏型脂肪酸结合蛋白在急性心肌梗死早期诊断中的临床应用价值

目的 探讨心脏型脂肪酸结合蛋白（H-FABP）在急性心肌梗死（acute myocardial infarction,AMI）早期诊断中的意义.方法 收集AMI 患者32例,另选择健康体检人员50例作为对照.AMI 患者入院后0～2 h、2～4 h、4～6 h检测血清H-FABP、cTnI、CK-MB,体检人员仅采血检测血清H-FABP.结果 入院后0～2 h、2～4 h、4～6 h,患者血清H-FABP的检测灵敏性、特异性均高于cTnI和CK-MB,差异有统计学意义（P＜0.05）.50例体检人员血清H-FABP平均浓度为（4.81±1.37）ng/mL;入院后0～2 h、2～4 h、4～6 h,患者血清H-FABP的平均浓度分别为（52.78±2.40）ng/mL、（85.49±1.88）ng/mL及（91.21±1.46）ng/mL.结论 将H-FABP检测用于AMI的早期诊断具有较高的临床应用价值.     

Elevation of creatine kinase in acute severe asthma is not of cardiac origin

OBJECTIVE: To study prospectively if, when plasma creatine kinase (CK) and plasma myoglobin are elevated, the origin of these abnormalities is cardiac or not, by measuring cardio-specific troponin T (cTT). METHOD: Fifteen patients with acute severe bronchial asthma (ASBA) were prospectively studied in the intensive care unit (ICU) with continuous electrocardiograph (ECG). Plasma CK, CK-MB, myoglobin and cTT were measured at 0, 4, 8, 12, 16 and 20 h in the ICU. RESULTS: Five out of 15 ASBA patients had elevated CK, four of them presenting with an increase in CK-MB. Plasma cTT was normal in every patient, including those with CK and/or myoglobin elevation. At admission to the ICU, myoglobin and CK were positively correlated (r = 0.760; p < 0.001). No patient was intubated. There was no difference in clinical signs or symptoms, medical history, laboratory values or ECG in patients with or without CK elevation. CONCLUSION: Patients admitted to an ICU for ASBA may present with an elevation of plasma CK, CK-MB and myoglobin not related to any heart injury. CK and CK-MB are not good markers of myocardial injury in ASBA patients due to the multitude of potential confounders. Therefore, troponin should be measured instead.     

The diagnostic value of troponin T and myoglobin levels in acute myocardial infarction: a study in Turkish patients

This study compares the diagnostic value of troponin T (TnT) and myoglobin with creatinine kinase (CK) for myocardial infarction (MI) in a tertiary care centre in a developing nation. The study group comprised 33 acute myocardial infarction patients and 27 healthy controls. Receiver operating characteristic curves for TnT, myoglobin and CK were drawn and areas under the curve calculated. At admission, myoglobin levels had greater diagnostic sensitivity than TnT or CK levels. After 2 h, myoglobin and TnT had equal sensitivity and specificity, whereas CK still had lower sensitivity than myoglobin and TnT. After 4 h there was no difference between the tests. It was concluded that myoglobin levels on admission and TnT at 2 h had the greatest diagnostic rate, whereas all the tests were similar after 4 h for MI.     

Serum markers in the emergency department diagnosis of acute myocardial infarction

No currently used cardiac-specific serum marker meets all the criteria for an "ideal" marker of AMI. No test is both highly sensitive and highly specific for acute infarction within 6 hours following the onset of chest pain, the timeframe of interest to most emergency physicians in making diagnostic and therapeutic decisions. Patients presenting to the ED with chest pain or other symptoms suggestive of acute cardiac ischemia therefore cannot make a diagnosis of AMI excluded on the basis of a single cardiac marker value obtained within a few hours after symptom onset. The total CK level is far too insensitive and nonspecific a test to be used to diagnose AMI. It retains its value, however, as a screening test, and serum of patients with abnormal total CK values should undergo a CK-MBmass assay. Elevation in CK-MB is a vital component of ultimate diagnosis of AMI, but levels of this marker are normal in one fourth to one half of patients with AMI at the time of ED presentation. The test is highly specific, however, and an abnormal value (particularly when it exceeds 5% of the total CK value) at any time in a patient with chest pain is highly suggestive of an AMI. There have been several improvements of CK-MB assay timing and subform quantification that appear highly useful for emergency physicians. Rapid serial CK-MB assessment greatly increases the diagnostic value of the assay in a timeframe suitable for ED purposes but unfortunately still misses about 10% of patients ultimately diagnosed with acute MI. Assays of CK-MB subforms have very high sensitivity, and, although unreliable within 4 hours of symptom onset, have excellent diagnostic value at 6 or more hours after chest pain begins. Automated test assays recently have become available and could prove applicable to ED settings. The cardiac troponins are highly useful as markers of acute coronary syndromes, rather than specifically of AMI, and abnormal values at any time following chest pain onset are highly predictive of an adverse cardiac event. The ED applicability of the troponins is severely limited, however, because values remain normal in most patients with acute cardiac events as long as 6 hours following symptom onset. Myoglobin appeared promising as a marker of early cardiac ischemia but appears to be only marginally more sensitive than CK-MB assays early after symptom onset and less sensitive than CK-MB at 8 hours or more after chest pain starts. Rapid serial myoglobin assessment, however, appears highly useful as an early marker of AMI. The marker has a very narrow diagnostic window. The clinician is left with several tests that are highly effective in correctly identifying patients with AMI (or at high risk for AMI), but none that can dependably exclude patients with acute coronary syndromes soon after chest pain onset. A prudent strategy when assessing ED patients with chest pain and nondiagnostic ECGs is to order CK-MB and troponin values on presentation in the hope of making an early diagnosis of AMI or unstable coronary syndrome. Although it is recognized that normal values obtained within 6 hours of symptom onset do not exclude an acute coronary syndrome, patients at low clinical risk and having normal cardiac marker tests could be provisionally admitted to low-acuity hospital settings or ED observation. After 6 to 8 hours of symptom duration has elapsed, the cardiac-specific markers are highly effective in diagnosing AMI, and such values obtained can be used more appropriately to make final disposition decisions. At no time should results of serum marker tests outweigh ECG findings or clinical assessment of the patient's risk and stability.