American journal of clinical pathology
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Am. J. Clin. Pathol. · Jul 2008
Comparative StudyComparison of emergency department patient classification by point-of-care and central laboratory methods for cardiac troponin I.
For patients admitted to the emergency department (ED) with suspected acute coronary syndrome, we compared results of a rapid, point-of-care whole blood assay for cardiac troponin I (Abbott i-STAT, Abbott Point-of-Care, East Windsor, NJ) (Tn-P) with an automated central laboratory plasma assay (Siemens TnI-Ultra, Siemens Medical Solutions Diagnostics, Tarrytown, NY) (Tn-U). Clinical data were obtained during a 6-month period during which ED patients were screened by Tn-P, with retesting of elevated results by Tn-U. ⋯ Of the negatives, 5.8% retested as elevated by Tn-U, but with levels no higher than 0.1 ng/mL (0.1 microg/L). Rapid whole blood testing for cardiac troponin I gave generally reliable patient classifications compared with plasma testing in the central laboratory, but besides missing small elevations, produced some apparent false-positives.
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Am. J. Clin. Pathol. · Jun 2008
Comparative StudyCardiac 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 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.
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Am. J. Clin. Pathol. · May 2008
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. ⋯ 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.
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Am. J. Clin. Pathol. · May 2008
Multicenter Study Comparative Study Clinical TrialA rapid point-of-care cardiac marker testing strategy facilitates the rapid diagnosis and management of chest pain patients in the emergency department.
We compared a rapid, point-of-care multimarker protocol with a single and serial troponin I (TnI)-only protocol in 5,244 patients admitted to the emergency department with chest pain. The diagnosis of acute myocardial infarction (AMI) was based on a doubling myoglobin level accompanied by at least a 50% increase in the creatine kinase (CK)-MB level with no detectable TnI; a doubling of myoglobin level together with any detectable TnI; or a TnI level of 0.4 ng/mL (0.4 microg/L) or more, irrespective of myoglobin or CK-MB results. By using these new criteria, 145 of 148 cases were positive for AMI (positive predictive value [PPV], 92.4%) and 3 were negative, which were also negative by the core laboratory TnI assay. ⋯ The TnI-only protocol had a sensitivity of 68.2% with an NPV of 99.1%. With lower TnI-only cutoffs, 4 patients had false-negative results, and a PPV of 36.4% was observed. Our rapid multimarker protocol seems superior to a TnI-only approach for rapidly triaging patients with chest pain or AMI.
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Am. J. Clin. Pathol. · Mar 2008
Iron deficiency anemia, beta-thalassemia minor, and anemia of chronic disease: a morphologic reappraisal.
We observed increased numbers of an infrequently referenced poikilocyte, the prekeratocyte, in iron deficiency anemia (IDA) compared with beta-thalassemia minor and anemia of chronic disease (ACD) and, therefore, chose to quantify these cells and other morphologic features in these anemias. Prekeratocytes were observed in 31 (78%) of 40 IDAs vs 11 (37%) of 30 beta-thalassemias (P = .001) and 5 (13%) of 40 ACDs (P < .001) and averaged 0.78 per 1,000 RBCs in IDA vs 0.21 in beta-thalassemia (P < .001) and 0.075 in ACD (P < .001). ⋯ Basophilic stippling was seen in only 5 (17%) of the beta-thalassemias. Our results lend quantitative support to prekeratocytes and pencil cells as morphologic features favoring the diagnosis of IDA but fail to support the diagnostic usefulness of target cells and basophilic stippling in discriminating IDA and beta-thalassemia minor.