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Biomedical subjects

L H Bernstein

Publications and source records attributed to L H Bernstein.

At least 127 records · Page 7Linked to original sources
PubMedDate not supplied

Strategic considerations in clinical laboratory management: a laboratory leadership role in clinical pathways. Establishing the laboratory's direct contribution to the institution's performance.

This clinical laboratory serves a unique, though incompletely recognized, function in medical care as the source, moderator, and conduit of vital information supporting the detection, confirmation, and monitoring of disease states. To carry out that function effectively, the laboratory must actively participate in developing clinical pathways based on medical programs. Clinical pathways define the operational and quality requirements for the services involved in meeting the medical program objectives. Because of the laboratory's unique position in the acquisition and flow of information, its contribution must continue as a planned process--based on accurate assessment of value, cost, and resource inputs--rather than in a discrete, event-driven manner. Two examples of clinical pathway development, partly given by the laboratory, illustrate its application in nutritional screening and monitoring for metabolic support and in emergency department admitting decisions on myocardial damage at Bridgeport Hospital (Bridgeport, CT). The paper suggest two activities, point-of-care testing and screening for fetal lung development, that could benefit considerably from clinical pathway information shared across the experiences of several institutions.

Chest Pain↗
PubMedDate not supplied

Outcomes research is the fifth discipline of the fifth generation of managed care: utility of a single troponin-T.

OBJECTIVE: The fifth generation of managed care is disease management. Diseases have measurable risk in providing laboratory and medical services. The link between managing services and managing risk can be aided by leveraging the laboratory. We wish to remodel laboratory services to fit the needs of the use, thereby using the laboratory for competitive advantage by redesigning a desired output using a formal structured process. Outcomes research is the systems framework for the remodeling process through the link of laboratory output to clinical and financial outcomes. A process redesign model connects the use of laboratory tests to improved medical services by leveraging resources to achieve measurable improvement over current results. This view of outcomes research seeks both competitive advantage and measurable improvements in quality. METHODOLOGY: This approach is illustrated by the patient presenting with chest pain (CP). A majority of the patients rule out for acute myocardial infarction (AMI), including patients with indigestion, shortness of breath, and other clinical findings. This is the basis for an emergency department (ED) CP observation unit to reduce coronary care unit admission rates. When the Goldman algorithm for discharging low-risk patients with CP from the ED using only clinical features and electrocardiographic findings proved difficult to implement, we turned to measuring the diagnostic efficiency of a new cardiac marker to replace the evolutionary changes in creatine kinase (CK) isoenzyme MB. The physicians making the decision were blinded to the results of the study. We fitted the expected characteristics of the test to the expected results for our program. The test was done on the presenting specimen of 293 evaluable patients with a median of 6.5 hours from the time of onset of CP to the time the specimen was drawn. The result was compared with the evolutionary pattern of CK-MB. RESULTS: The sensitivity of the test at presentation to the ED was 85% compared with < 50% for the presenting CK-MB, the false negative results taken earlier than 3 hours or 10 days after the onset of symptoms. Troponin-T effectively identifies non Q-wave AMI much earlier than the CK-MB. This study led to a prospective randomized clinical trial to demonstrate an improved medical and financial benefit from an early rule in or rule out of severe coronary artery ischemia. CONCLUSION: The study supports our hypothesis that the laboratory can systematically redesign its technology strategy and participate in the construction of a clinical pathway for the discharge from ED or admitting decisions with a test 98% sensitive for identifying patients with serious coronary ischemia by 3.5 hours after the onset of symptoms.

Biomarkers↗
PubMedDate not supplied

Diagnosis of myocardial infarction: integration of serum markers and clinical descriptors using information theory.

OBJECTIVE: We examine the use of information theory applied to a single cardiac troponin T (cTnT) (first generation monoclonal; Boehringer Mannheim Corp., Indianapolis, Indiana) used with the character of chest pain, electrocardiography (ECG) and serial ECG changes in the evaluation of acute myocardial infarction (AMI). We combined a single measure of cTnT (blinded to the investigators) with a creatine kinase MB isoenzyme (CK-MB) measurement to discover the best decision value for this test in a study of 293 consecutive patients presenting to the emergency department with symptoms warranting exclusion of AMI. METHODS: The decision value for determining whether cTnT is positive or negative was determined independently of the final diagnosis by examining the information in the cTnT and CKMB data. Using information theory, an autocorrelation matrix with a one-to-one pairing of the CKMB and troponin T was constructed. The effective information, also known as Kullback entropy, assigned the values for troponin T and for CKMB that have the lowest frequency of misclassification error. The Kullback entropy is determined by subtracting the data entropy from the maximum entropy of the data set in which the information has been destroyed. The assignment of the optimum decision values was made independently of the clinical diagnoses without the construction of a receiver-operator characteristic curve (ROC). The final diagnosis of AMI was independently determined by the clinicians and entered into the medical record. RESULTS: The decision value for cTnT was 0.1 ng/ml as determined by the the information in the data. The method was validated within the same study by mapping the results so obtained into the diagnoses obtained independently by the clinicians using all of the methods at their disposal. The cTnT was different in AMI (n = 60) compared with non-AMI patients (n = 233) (2.08 +/- 0.21 vs. 0.07 +/- 0.10; p < .0001). CONCLUSION: Information theory provides a strong framework and methodology for determining the decision value for cTnT which minimizes misclassification errors at 0.1 ng/ml. The result has a strong correlation with other features in detecting AMI in patients presenting with chest pain.

Creatine Kinase↗
PubMedDate not supplied

Evaluating a new graphical ordinal logit method (GOLDminer) in the diagnosis of myocardial infarction utilizing clinical features and laboratory data.

OBJECTIVE: We used a new graphical ordinal logit method (GOLDminer) to assess a single cardiac troponin T (cTnT) analysis at the time of admission (first generation monoclonal; Roche BMC Corp., Indianapolis, Indiana), the character of chest pain, and electrocardiographic (ECG)findings in predicting the likelihood of acute myocardial infarction (AMI) in patients presenting with suspected myocardial ischemia. The final diagnosis of AMI was based on serial ECG findings and evolution of CKMB isoenzyme levels in conjunction with clinical findings. SUBJECTS: The study population consisted of 293 consecutive patients who presented at a mean of six hours after onset of chest pain or associated symptoms warranting a "rule-out" for AMI assessment to a university-affiliated community hospital. RESULTS: The odds-ratio for an elevated cTnT (> 0. 1 ng/ml) in AMI was 22.2:1. There was an association between typical chest pain and cTnT (chi square = 78.23, p < .0001) and between abnormal ECG findings and cTnT (chi square = 108, p < .0001). The cTnT yielded diagnostic benefit in addition to chest pain characteristics and ECG findings in AMI. We present the odds-ratios for the combined features in GOLDminer plots. CONCLUSION: We demonstrate how the odds-ratios for AMI are obtained after scaling continuous to ordinal the values for a single cTnT determination alone and with other features in patients presenting with chest pain.

Creatine Kinase↗
PubMedDate not supplied

Carcinoembryonic antigen in effusions. A diagnostic adjunct to cytology.

A total of 189 effusion specimens (100 benign and 89 malignant) submitted for cytologic examination were assayed for carcinoembryonic antigen (CEA) by an enzyme immunoassay to determine whether the addition of CEA evaluation to cytologic study would improve the diagnostic accuracy for the detection of malignancy. The sensitivity and specificity were 78% and 90%, respectively, for a cytologic diagnosis of malignancy and 68% and 99%, respectively, for a positive CEA (greater than 5 ng/mL). CEA assay was negative in the most common epithelial malignancies of the female genital tract (15 of 17 cases), mesotheliomas (5), lymphomas (7) and alveolar-cell carcinoma of lung (1). CEA assay was positive in 55 of 89 cases of malignancy, including 14 cases with cytologically negative malignant effusions. The CEA assay sensitivity for lung carcinoma (95% for adenocarcinoma, 100% for oat-cell carcinoma and 100% for carcinosarcoma), breast carcinoma (95%), and gastrointestinal carcinoma (100%) were all over 90%. No significant difference in the levels of CEA was noted between gastrointestinal and lung adenocarcinomas. Oat-cell carcinomas and squamous-cell carcinomas had lower values. In cases of an effusion with an unknown primary, an elevated CEA in the fluid is diagnostic of metastatic carcinoma arising from the breast, lung or gastrointestinal tract.

Breast Neoplasms↗
PubMedDate not supplied

Preliminary use of linear discriminant function to predict success or failure of kidney transplant.

Adenylate kinase (AK) activity appears in serum or in urine as a result of tissue destruction. The serum and urine AK activity are normally very low (as previously reported). These studies were carried out to determine the usefulness of measuring the appearance of urinary AK activity in the detection of renal transplant crisis. Serum creatinine determinations, the results of nuclear medicine studies and other clinical evidence, were compared with urinary AK activity during renal transplant crises. As a result of these studies, a model is proposed which assesses the reliability of predictors of success or failure of kidney transplants by step-wise discriminant function analysis using adenylate kinase and creatinine clearance measurements of urine to separate patients into two groups based on whether the kidney transplant was removed or retained postoperatively. The effectiveness of the predictors used in the analyses changed with respect to their importance during nonhomogeneous time intervals of analysis.

Adenylate Kinase↗