Evaluation of the rapid Quidel Sofia Lyme fluorescent immunoassay as a first-tier test in a modified 2-tier testing algorithm for Lyme disease: A comparison with the Zeus ELISA Borrelia VlsE1/pepC10 lgG/IgM assay followed by the Zeus monovalent IgM/IgG confirmatory assay.

OBJECTIVES: Recently modified 2-tier testing (MTTT) algorithms using 2 enzyme immunoassays (EIAs) as opposed to an EIA followed by immunoblot have been approved by the US Food and Drug Administration (FDA) for the screening and confirmation of Lyme disease. The Quidel Sofia Lyme fluorescent immunoassay is a rapid lateral-flow method that can be performed in real time, permitting on-demand testing. We evaluated the performance of the Sofia assay as a first-tier test in an MTTT algorithm. METHODS: We compared the Sofia Lyme test with the Zeus ELISA Borrelia VlsE1/pepC10 lgG/IgM test, followed by the Zeus monovalent IgM/IgG EIA as the confirmatory test. RESULTS: When used as a first-tier test compared with a standard Zeus MTTT assay, the positive percentage agreement was 91.4%% (95% CI, 77.6%-97.0%). The negative percentage agreement was 100% (95% CI, 94.0%-100%). The overall agreement was 98.3% (95% CI, 94.2%-99.4%). κ = 0.945, indicating "almost perfect agreement." CONCLUSIONS: The Sofia Lyme test performs well compared with an FDA-approved MTTT.

Detection and localization of early- and late-stage cancers using platelet RNA.

Cancer patients benefit from early tumor detection since treatment outcomes are more favorable for less advanced cancers. Platelets are involved in cancer progression and are considered a promising biosource for cancer detection, as they alter their RNA content upon local and systemic cues. We show that tumor-educated platelet (TEP) RNA-based blood tests enable the detection of 18 cancer types. With 99% specificity in asymptomatic controls, thromboSeq correctly detected the presence of cancer in two-thirds of 1,096 blood samples from stage I-IV cancer patients and in half of 352 stage I-III tumors. Symptomatic controls, including inflammatory and cardiovascular diseases, and benign tumors had increased false-positive test results with an average specificity of 78%. Moreover, thromboSeq determined the tumor site of origin in five different tumor types correctly in over 80% of the cancer patients. These results highlight the potential properties of TEP-derived RNA panels to supplement current approaches for blood-based cancer screening.

Laboratory Blood-Based Testing for Non-Lyme Disease Tick-Borne Infections at a National Reference Laboratory.

OBJECTIVES: We evaluated trends in non-Lyme disease tick-borne disease (NLTBI) testing at a national reference laboratory. METHODS: Testing data performed at Quest Diagnostics during 2010 to 2016 were analyzed nationally and at the state level. RESULTS: Testing and positivity for most NLTBIs increased dramatically from 2010 through 2016 based on testing from a large reference laboratory. The number of positive cases, though not as stringent as criteria for public health reporting, generally exceeds that reported by the Centers for Disease Control and Prevention. The frequency of NLTBI in the US is seasonal but testing activity and positive test results are observed throughout all months of the year. Positive results for NLTBI testing mostly originated from a limited number of states, indicating the geographic concentration and distribution of NLTBIs reported in this study. CONCLUSIONS: This report provides an important complementary source of data to best understand trends in and spread of NLTBI.

Laboratory Blood-Based Testing for Lyme Disease at a National Reference Laboratory.

OBJECTIVES: We evaluated trends in Lyme disease (LD) testing at a national reference laboratory. METHODS: LD screening enzyme immunoassay and Western blot testing data performed at Quest Diagnostics during 2010 to 2016 were analyzed nationally and at the state level. RESULTS: Overall, 593,800 (11.3%) results were positive of 5,255,636 tests. There was an increase in the rate of positivity over the last 2 years of the study and an increase in the number of positive tests in 2016. Positive tests were observed in all 50 states and the District of Columbia. New York had the most positive tests, whereas Connecticut had the highest positivity rate when normalized to state populations. Some states with historically low rates of LD (eg, Texas, Florida, and California) showed significant increases in testing and positivity rates over time. CONCLUSIONS: LD testing and positivity have increased in recent years, including in states not historically associated with the disease.

Cardiac biomarkers, electrolytes, and other analytes in collapsed marathon runners: implications for the evaluation of runners following competition.

We measured analytes in collapsed Boston Marathon runners to compare with changes in asymptomatic runners. Of collapsed runners at the 2007 marathon, 18.2% had a measurable cardiac troponin T (cTnT) value with a mean postrace level of 0.017 ng/mL (0.017 microg/L; SD, 0.02 ng/mL [0.02 microg/L]). Three subjects had cTnT values above the cutoff (0.10 ng/mL [0.10 microg/L]) typically used for the diagnosis of acute myocardial infarction. The mean and median N-terminal pro-B-type natriuretic peptide levels were 73 ng/L (SD, 77.3 ng/L) and 54.3 ng/L (interquartile range, 22.8-87.3 ng/L), respectively, in collapsed runners. Only 4.9% had values more than the age-specific normal value (<125 ng/L for subjects younger than 75 years). In collapsed subjects at the 2006 marathon, 18.0% had an abnormal sodium value, including 18 cases of hypernatremia and 7 cases of hyponatremia. The ionized calcium level was low in 49% of subjects, and the ionized magnesium level was low in 19.5% and elevated in 1 subject. The blood lactate level was elevated in 95% of subjects. The frequency of elevated postrace cTnT levels in collapsed athletes after endurance exercise is similar to that in asymptomatic runners. Other metabolic abnormalities, including hypernatremia, hyponatremia, low ionized calcium and magnesium levels, and lactic acidosis may contribute to muscle fatigue and collapse.

Implementation of point-of-care rapid urine testing for drugs of abuse in the emergency department of an academic medical center: impact on test utilization and ED length of stay.

We evaluated the impact of implementing a point-of-care (POC) rapid urine test panel for drugs of abuse on turnaround time (TAT), emergency department length of stay (LOS), and laboratory test utilization patterns. The mean TAT from sample collection to results reporting decreased by 69.4%, from 108 to 33 minutes, the mean LOS from 11.1 to 8.1 hours (27% P < .0001), and the median LOS from 8.0 to 7.0 hours (13% P = .0017). A method crossover between the POC and central laboratory methods revealed differences in sensitivity and specificity. Overall, there was no clear preference for either method. Differences in performance for individual drug classes were reconciled by providing interpretive comments with POC results. Following implementation, use of urine testing for drugs of abuse increased by 30%, which was offset by fewer requests for extended toxicology testing in the central laboratory and more selective ordering of toxicology tests not on the POC panel (alcohols and analgesics). The implementation of a POC urine test panel for drugs of abuse decreased LOS and TAT and essentially replaced central laboratory testing for drugs of abuse. Differences in sensitivity and specificity between POC and central laboratory results require provision of interpretive comments with results.

Laboratory Testing for Tick-Borne Infections in a Large Northeastern Academic Medical Center: An 11-Year Experience.

OBJECTIVES: We evaluated changes in the testing menu, volume, and positivity rates for tick-borne illnesses in a New England medical center over an 11-year time frame. METHODS: Testing data were obtained by a retrospective review utilizing searchable data from a laboratory information system archive. RESULTS: Testing for tick-borne infections (TBI) increased 5.3-fold over an 11-year time period and the number of positive test results increased threefold. Annual rates for Lyme serology positivity varied from 14% to 29% and for western blot confirmation from 26% to 48%. Test volumes and the number of positive results increased for all TBI endemic to our region. CONCLUSIONS: Our results confirm national trends suggesting increasing rates of TBI and substantially increased testing. This may reflect a greater incidence of TBI in our region and/or increased awareness of these infections.

Myocardial injury and ventricular dysfunction related to training levels among nonelite participants in the Boston marathon.

BACKGROUND: Multiple studies have individually documented cardiac dysfunction and biochemical evidence of cardiac injury after endurance sports; however, convincing associations between the two are lacking. We aimed to determine the associations between the observed transient cardiac dysfunction and biochemical evidence of cardiac injury in amateur participants in endurance sports and to elicit the risk factors for the observed injury and dysfunction. METHODS AND RESULTS: We screened 60 nonelite participants, before and after the 2004 and 2005 Boston Marathons, with echocardiography and serum biomarkers. Echocardiography included conventional measures as well as tissue Doppler-derived strain and strain rate imaging. Biomarkers included cardiac troponin T (cTnT) and N-terminal pro-brain natriuretic peptide (NT-proBNP). All subjects completed the race. Echocardiographic abnormalities after the race included altered diastolic filling, increased pulmonary pressures and right ventricular dimensions, and decreased right ventricular systolic function. At baseline, all had unmeasurable troponin. After the race, > 60% of participants had increased cTnT > 99th percentile of normal (> 0.01 ng/mL), whereas 40% had a cTnT level at or above the decision limit for acute myocardial necrosis (> or = 0.03 ng/mL). After the race, NT-proBNP concentrations increased from 63 (interquartile range [IQR] 21 to 81) pg/mL to 131 (IQR 82 to 193) pg/mL (P<0.001). The increase in biomarkers correlated with post-race diastolic dysfunction, increased pulmonary pressures, and right ventricular dysfunction (right ventricular mid strain, r=-0.70, P<0.001) and inversely with training mileage (r=-0.71, P<0.001). Compared with athletes training > 45 miles/wk, athletes who trained < or = 35 miles/wk demonstrated increased pulmonary pressures, right ventricular dysfunction (mid strain 16+/-5% versus 25+/-4%, P<0.001), myocyte injury (cTnT 0.09 versus < 0.01 ng/mL, P<0.001), and stress (NT-proBNP 182 versus 106 pg/mL, P<0.001). CONCLUSIONS: Completion of a marathon is associated with correlative biochemical and echocardiographic evidence of cardiac dysfunction and injury, and this risk is increased in those participants with less training.

Association of atrial fibrillation and amino-terminal pro-brain natriuretic peptide concentrations in dyspneic subjects with and without acute heart failure: results from the ProBNP Investigation of Dyspnea in the Emergency Department (PRIDE) study.

BACKGROUND: Amino-terminal pro-brain natriuretic peptide (NT-proBNP) testing is useful for diagnosis or exclusion of heart failure (HF) in dyspneic patients. Atrial fibrillation (AF) may cause dyspnea in the absence of acute HF and may also affect plasma levels of NT-proBNP. METHODS: We prospectively enrolled 599 patients presenting with dyspnea to the emergency department and obtained a blood sample for NT-proBNP measurement. The diagnosis of AF was identified via presentation electrocardiogram. A final diagnosis of HF was determined by blinded study physicians using all available hospital records for each subject through 60 days of follow-up. We assessed the association between the presence of AF and level of NT-proBNP in subsets of patients with and without HF. RESULTS: Of 599 dyspneic patients, 75 (13%) were in AF at presentation; these patients had significantly higher median NT-proBNP levels when compared with those without AF (2934 vs 294 pg/mL, P < .0001). Among patients with acute HF, AF was present in 28%; NT-proBNP levels were lower in those with AF versus those without (3488 vs 4492 pg/mL, P < .001), but AF was not independently associated with NT-proBNP after multivariable adjustment. In patients without acute HF, median NT-proBNP concentrations were significantly higher in those with AF than in those without (932 vs 121 pg/mL, P = .02); in these subjects, AF was the strongest predictor of an NT-proBNP concentration in a range consistent with acute HF (odds ratio 9.94, 95% CI 2.97-33.3, P < .001). CONCLUSION: Atrial fibrillation is associated with higher NT-proBNP concentrations in dyspneic patients, particularly in those without acute HF.

Multi-center validation of the Response Biomedical Corporation RAMP NT-proBNP assay with comparison to the Roche Diagnostics GmbH Elecsys proBNP assay.

BACKGROUND: NT-proBNP measurements aid in the evaluation of patients with suspected heart failure (HF) and may facilitate risk stratification in patients with HF and acute coronary syndrome (ACS). Point-of-care (POC) assays may provide more timely results and potentially improve patient outcomes. METHODS: We evaluated the analytical performance of the Response Biomedical Corporation whole blood RAMP amino-terminal pro-B type natriuretic peptide (NT-proBNP) POC assay compared to the Roche Elecsys proBNP (NT-proBNP) assay. RESULTS: Intra-day and total imprecision (% CV) ranged from 5.5% to 10.3% at 140, 449 and 1675 ng/L. The lowest concentration that yields a 20% CV was 57 ng/L. The lower limit of detection was 18 ng/L. The upper limit of linearity was validated to 23,428 ng/L with an average recovery of 95%. Correlation by Passing and Bablok regression yielded RAMP=1.01 Elecsys+14.6, r=0.98 (n=540; range of Elecsys values <5 to >35,000). Concordance of RAMP versus Elecsys using cut-offs of 125 ng/L for subjects <75 years and 450 ng/L for subjects > or =75 was 92% (95% CI 89-94%) for a group consisting of 127 apparently healthy individuals and 208 non-healthy subjects without HF, and 99% (95% CI 97-100%) for patients with HF, using the New York Heart Association (NYHA) functional classification. Overall, 80%, 87%, 97% and 100% of the RAMP results and 77%, 85%, 96% and 100% of the Elecsys results were greater than the age appropriate cut-off for NYHA I, II, III or IV groups. For both the RAMP and Elecsys results, the median NT-proBNP value was statistically correlated (increasing) with NYHA I, II, III or IV groups, respectively (p<0.0001), with no significant difference between the two methods. CONCLUSIONS: The POC Response Biomedical RAMP NT-proBNP assay provides comparable results that measured on the FDA cleared Roche Elecsys central laboratory platform.

Total and ionized magnesium testing in the surgical intensive care unit - Opportunities for improved laboratory and pharmacy utilization.

PURPOSE: Ionized fraction (iMg) is the physiologically active form of magnesium (Mg); total Mg may not accurately reflect iMg status. Erroneously "low" Mg levels may result in unnecessary repetitive testing. MATERIALS AND METHODS: From 11/2015 to 01/2016, patients ordered for Mg from a pilot ICU also had iMg tested. Weighted kappa statistic was used to assess agreement between Mg categories (low, normal, high). Predictors of unnecessary repeated Mg testing and repletion using data were explored through logistic regression models using GEE techniques to account for repeated measurements in both bivariate and multivariable analyses. RESULTS: There were 470Mg/iMg paired measurements from 173 patients. The weighted kappa statistic was 0.35 (95%CI 0.27-0.43) indicating poor agreement in assessment of magnesium status. Of the 34Mg samples reported as "low", only 6 (18%) were considered "low" using concurrent iMg testing. In the multivariable models, history of atrial fibrillation (aOR=1.61, 95%CI 1.16-2.21, p=0.004) and concomitant metoclopramide (aOR=1.71, 95%CI 1.03-2.81, p=0.036) were significant predictors of unnecessary repeat Mg testing. CONCLUSIONS: In the surgical ICU, categorical agreement (low, normal, high) was poor between Mg and iMg. Over 80% of "low" total Mg values are erroneous and may result in unnecessary additional measurements and repletion.

Elevated admission N-terminal pro-brain natriuretic peptide level predicts the development of atrial fibrillation in general surgical intensive care unit patients.

BACKGROUND: New onset atrial fibrillation (AF) in critically ill surgical patients is associated with significant morbidity and increased mortality. N-terminal pro-B type natriuretic peptide (NT-proBNP) is released by cardiomyocytes in response to stress and may predict AF development after surgery. We hypothesized that elevated NT-proBNP level at surgical intensive care unit (ICU) admission predicts AF development in a general surgical and trauma population. METHODS: From July to October 2015, NT-proBNP concentrations were measured at ICU admission. Abnormal NT-proBNP concentrations were defined by age-adjusted cut-offs. We examined the relationship between the development of AF and demographics, clinical variables, and NT-proBNP level using univariate analysis and a multivariable logistic regression model. RESULTS: Three hundred eighty-seven subjects were included in the cohort, none of whom were in AF at ICU admission. The median age was 63 years (52-73 years), and 40.3% were women. The risk of developing AF was higher for abnormal versus normal NT-proBNP (22% vs. 4%; p < 0.0001). Using optimal derived cutoffs (regardless of age), the risk of developing AF was 2% for NT-proBNP less than 600 ng/L, 15% for NT-proBNP of 600 ng/L to 1,999 ng/L, and 27% for NT-proBNP of 2,000 ng/L or greater. Multiple logistic regression analysis identified three independent predictors for new-onset AF: age, older than 70 years (odds ratio [OR], 3.7, 95% confidence interval [CI], 1.5-9.3), history of AF (OR, 25.3; 95% CI, 9.6-67.0), and NT-proBNP of 600 or greater (OR, 4.3; 95% CI, 1.3-14.2). When none or only one predictor was present, AF incidence was less than 1%. When all three predictors were present, AF incidence was 66%. For subjects 70 years or older but no history of AF, AF incidence was 12.8% when NT-proBNP was 600 or greater compared with 0% when NT-proBNP was less than 600. For subjects younger than 70 years with a history of AF, AF incidence was 44.4% when NT-proBNP was 600 or higher compared to 0% when NT-proBNP was less than 600. CONCLUSION: Elevated NT-proBNP at ICU admission in general surgical and trauma patients is predictive of AF development in the first 3 ICU days. Addition of NT-proBNP measurement to known risk factors can improve predictive power and identify patients who might potentially benefit from evidence-based prophylactic treatment for AF.

Swarm Intelligence-Enhanced Detection of Non-Small-Cell Lung Cancer Using Tumor-Educated Platelets.

Blood-based liquid biopsies, including tumor-educated blood platelets (TEPs), have emerged as promising biomarker sources for non-invasive detection of cancer. Here we demonstrate that particle-swarm optimization (PSO)-enhanced algorithms enable efficient selection of RNA biomarker panels from platelet RNA-sequencing libraries (n = 779). This resulted in accurate TEP-based detection of early- and late-stage non-small-cell lung cancer (n = 518 late-stage validation cohort, accuracy, 88%; AUC, 0.94; 95% CI, 0.92-0.96; p < 0.001; n = 106 early-stage validation cohort, accuracy, 81%; AUC, 0.89; 95% CI, 0.83-0.95; p < 0.001), independent of age of the individuals, smoking habits, whole-blood storage time, and various inflammatory conditions. PSO enabled selection of gene panels to diagnose cancer from TEPs, suggesting that swarm intelligence may also benefit the optimization of diagnostics readout of other liquid biopsy biosources.

Measurement of a plasma stroke biomarker panel and cardiac troponin T in marathon runners before and after the 2005 Boston marathon.

We report changes in cardiac troponin-T (TnT) and a new plasma stroke biomarker panel (D-dimer, B-natriuretic peptide [BNP], matrix metalloproteinase-9 [MMP-9], S-100 b, Biosite Diagnostics, San Diego, CA) in 30 nonprofessional marathon runners before and immediately after the 2005 Boston Marathon. Following competition, there was a statistically significant increase in MMP-9 (P < .001) and D dimer (P < .001). Nonsignificant changes in S-100 b and BNP were observed. Premarathon and postmarathon values for a multimarker stroke index increased from 0.97 (normal) to 3.5 (low risk or more; P < .001). Two subjects had index values more than the high-risk cutoff value. Mean TnT premarathon and postmarathon levels increased (from <0.01 to 0.03 ng/mL; P < .0001). After the marathon, with a cutoff value of 0.05 ng/mL, 7 runners (23%) had values above the manufacturer's recommended cutoff for myocardial damage. Although biochemical evidence of myocardial damage following strenuous exercise may reflect myocardial stunning or subclinical ischemia, the changes in the stroke index and values for individual stroke markers may reflect a systemic inflammatory response to exertional rhabdomyolysis which is common, but the possibility of subclinical central nervous system damage cannot be excluded.

Natriuretic peptide testing for the evaluation of critically ill patients with shock in the intensive care unit: a prospective cohort study.

INTRODUCTION: Amino-terminal pro-brain natriuretic peptide (NT-proBNP) is useful in evaluating heart failure, but its role in evaluating patients with shock in the intensive care unit (ICU) is not clear. METHOD: Forty-nine consecutive patients in four different ICUs with shock of various types and with an indication for pulmonary artery catheter placement were evaluated. Analyses for NT-proBNP were performed on blood obtained at the time of catheter placement and results were correlated with pulmonary artery catheter findings. Logistic regression identified independent predictors of mortality. RESULTS: A wide range of NT-proBNP levels were observed (106 to >35,000 pg/ml). There was no difference in median NT-proBNP levels between patients with a cardiac and those with a noncardiac origin to their shock (3,046 pg/ml versus 2,959 pg/ml; P = 0.80), but an NT-proBNP value below 1,200 pg/ml had a negative predictive value of 92% for cardiogenic shock. NT-proBNP levels did not correlate with filling pressures or hemodynamics (findings not significant). NT-proBNP concentrations were higher in patients who died in the ICU (11,859 versus 2,534 pg/ml; P = 0.03), and the mortality rate of patients in the highest log-quartile of NT-proBNP (66.7%) was significantly higher than those in other log-quartiles (P < 0.001); NT-proBNP independently predicted ICU mortality (odds ratio 14.8, 95% confidence interval 1.8-125.2; P = 0.013), and was superior to Acute Physiology and Chronic Health Evaluation II score and brain natriuretic peptide in this regard. CONCLUSION: Elevated levels of NT-proBNP do not necessarily correlate with high filling pressures among patients with ICU shock, but marked elevation in NT-proBNP is strongly associated with ICU death. Low NT-proBNP values in patients with ICU shock identifed those at lower risk for death, and may be useful in excluding the need for pulmonary artery catheter placement in such patients.

Can a Point-of-Care Troponin I Assay be as Good as a Central Laboratory Assay? A MIDAS Investigation.

BACKGROUND: We aimed to compare the diagnostic accuracy of the Alere Triage Cardio3 Tropinin I (TnI) assay (Alere, Inc., USA) and the PathFast cTnI-II (Mitsubishi Chemical Medience Corporation, Japan) against the central laboratory assay Singulex Erenna TnI assay (Singulex, USA). METHODS: Using the Markers in the Diagnosis of Acute Coronary Syndromes (MIDAS) study population, we evaluated the ability of three different assays to identify patients with acute myocardial infarction (AMI). The MIDAS dataset, described elsewhere, is a prospective multicenter dataset of emergency department (ED) patients with suspected acute coronary syndrome (ACS) and a planned objective myocardial perfusion evaluation. Myocardial infarction (MI) was diagnosed by central adjudication. RESULTS: The C-statistic with 95% confidence intervals (CI) for diagnosing MI by using a common population (n=241) was 0.95 (0.91-0.99), 0.95 (0.91-0.99), and 0.93 (0.89-0.97) for the Triage, Singulex, and PathFast assays, respectively. Of samples with detectable troponin, the absolute values had high Pearson (R(P)) and Spearman (R(S)) correlations and were R(P)=0.94 and R(S)=0.94 for Triage vs Singulex, R(P)=0.93 and R(S)=0.85 for Triage vs PathFast, and R(P)=0.89 and R(S)=0.73 for PathFast vs Singulex. CONCLUSIONS: In a single comparative population of ED patients with suspected ACS, the Triage Cardio3 TnI, PathFast, and Singulex TnI assays provided similar diagnostic performance for MI.

A comparison of cardiac troponin T and creatine kinase-MB for patient evaluation after cardiac surgery.

OBJECTIVES: The aim of this study was to assess the role of serum markers of myocardial necrosis after cardiac surgery. BACKGROUND: The role of serum troponin T (TnT) and creatine kinase-MB (CK-MB) for the risk stratification of patients after cardiac surgery remains undefined. METHODS: Serum levels of TnT and CK-MB were measured from 224 patients every 8 h after cardiac surgery. The results of serum cardiac marker testing were correlated with adverse events, including new myocardial infarction (MI), cardiogenic shock or death. Univariable analysis identified factors predictive of complications, while stepwise logistic regression identified independent predictors of postoperative complications. RESULTS: Cardiac marker elevation was universal after cardiac surgery. At all time points measured, compared with those patients without complications, the TnT levels from patients with complications were more significantly elevated (all: p < 0.0005). In contrast, among identically timed specimens, the levels of CK-MB from complicated patients were less reliably discriminatory. Multivariable analysis suggested that a TnT level in the highest quintile (> or = 1.58 ng/ml) was the strongest predictor of complications, including death (post-op, odds ratio [OR] = 31.0, 95% confidence interval [CI] = 3.67 to 263.1, p = 0.002) or shock (post-op: OR = 18.9, 95% CI = 2.29 to 156.1, p = 0.006; 18 h to 24 h: OR = 30.7, 95% CI = 3.75 to 250.7, p = 0.001), as well as the composite end points of death/MI (18 h to 24 h: OR = 60.1, 95% CI = 7.34 to 492.1, p < 0.0005), shock/MI (post-op: OR = 23.3, 95% CI = 2.82 to 191.4, p = 0.003; 18 h to 24 h: OR = 37.8, 95% CI = 4.66 to 307.3, p = 0.001) or death/shock/MI (post-op: OR = 20.0, 95% CI = 2.81 to 142.0, p = 0.003; 18 h to 24 h: OR = 67.4, 95% CI = 6.96 to 652.3, p < 0.0005). In contrast, in the presence of TnT, the results of CK-MB measurement added no independent prognostic information. CONCLUSIONS: Troponin T is superior to CK-MB for the prediction of impending complications after cardiac surgical procedures.

The N-terminal Pro-BNP investigation of dyspnea in the emergency department (PRIDE) study.

The utility of aminoterminal pro-brain natriuretic peptide (NT-proBNP) testing in the emergency department to rule out acute congestive heart failure (CHF) and the optimal cutpoints for this use are not established. We conducted a prospective study of 600 patients who presented in the emergency department with dyspnea. The clinical diagnosis of acute CHF was determined by study physicians who were blinded to NT-proBNP results. The primary end point was a comparison of NT-proBNP results with the clinical assessment of the managing physician for identifying acute CHF. The median NT-proBNP level among 209 patients (35%) who had acute CHF was 4,054 versus 131 pg/ml among 390 patients (65%) who did not (p <0.001). NT-proBNP at cutpoints of >450 pg/ml for patients <50 years of age and >900 pg/ml for patients >or=50 years of age were highly sensitive and specific for the diagnosis of acute CHF (p <0.001). An NT-proBNP level <300 pg/ml was optimal for ruling out acute CHF, with a negative predictive value of 99%. Increased NT-proBNP was the strongest independent predictor of a final diagnosis of acute CHF (odds ratio 44, 95% confidence interval 21.0 to 91.0, p <0.0001). NT-proBNP testing alone was superior to clinical judgment alone for diagnosing acute CHF (p = 0.006); NT-proBNP plus clinical judgment was superior to NT-proBNP or clinical judgment alone. NT-proBNP measurement is a valuable addition to standard clinical assessment for the identification and exclusion of acute CHF in the emergency department setting.

Cardiac troponin T elevation after coronary artery bypass grafting is associated with increased one-year mortality.

The results of the present study extend the value of assessing troponin T for the prediction of mortality rate 1 year after coronary artery bypass grafting; this study supports previous work that demonstrated the value of postoperative assessment of troponin T for the prediction of in-hospital adverse outcome after coronary artery bypass grafting.

Effect of marathon running on hematologic and biochemical laboratory parameters, including cardiac markers.

Participants in marathon races may require medical attention and the performance of laboratory assays. We report the changes in basic biochemical parameters, cardiac markers, CBC counts, and WBC differentials observed in participants in a marathon before, within 4 hours, and 24 hours after a race. The concentrations of glucose, total protein, albumin, uric acid, calcium, phosphorus, serum urea nitrogen, creatinine, bilirubin, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, total creatine kinase, creatine kinase-MB, myoglobin, and the anion gap were increased after the race, consistent with the effects of exertional rhabdomyolysis and hemolysis. The increase in WBC counts was due mainly to neutrophilia and monocytosis, with a relative decrease in circulating lymphocytes, consistent with an inflammatory reaction to tissue injury. A significant percentage of laboratory results were outside the standard reference ranges, indicating that modified reference ranges derivedfrom marathon runners might be more appropriatefor this population. We provide a table of modified reference ranges (or expected ranges) for basic biochemical, cardiac, and hematologic laboratory parameters for marathon runners.