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A goal-setting approach was used to examine the way in which 62 patients with closed head injuries or cerebral vascular accidents and 47 orthopedic control patients alter their performance on a four-choice reaction time (RT) task. Both patient groups were randomly assigned to two conditions: one in which a specific and high goal was assigned and one in which a "do your best" goal was given. Statistical analysis indicated that patients with a specific and high goal responded faster than patients with a "do your best" goal. No clinical or neuropsychological variables (e.g., attention, memory) had a moderating influence on the goal setting effect. These results demonstrate that goal setting as a motivational technique is a reliable and robust technique and can enhance performance (intensity of behavior) not only in healthy participants but also in brain-damaged patients.

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The portable blood gas analyzer OPTI Critical Care Analyzer was evaluated in comparison to routine laboratory assays using heparinized blood samples of adults and newborns. Within-run imprecision studies were performed with native blood using tonometry to adjust blood gas concentrations. The results obtained show a very close agreement between the OPTI system and the comparison methods for all parameters tested: hemoglobin (y=1.00x-0.2 g/l, r=0.997, n=81), sodium (y=1.13x-18.7 mmol/l, r=0.951, n=79), potassium (y=1.03x-0.04 mmol/l, r=0.972, n=79), pH (y=1.03x-0.29, r=0.958, n=57), pCO2 (y=1.03x-1.14 mm Hg, r=0.988, n=57) and pO2 (y=1.07x-0.85 mm Hg, r=0.995, n=57). The coefficients of variation for the within-run imprecision were below 1.1% for sodium and hemoglobin, and below 2.6% for all other parameters, except for pCO(2) with coefficients of variation up to 3.6% at low calibration gas concentrations. Due to this analytical performance and its portability, the OPTI system is well suited for low to medium test frequencies and immediate use in emergency rooms, intensive care or surgery units.

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We present the results of a multicenter evaluation of a new point-of-care system (Cardiac Reader) for the quantitative determination of cardiac troponin T (CARDIAC T Quantitative test) and myoglobin (CARDIAC M test) in whole blood samples. The Cardiac Reader is a CCD camera that optically reads the immunochemical test strips. The measuring range is 0.1 to 3 microg/l for CARDIAC T Quantitative and 30 to 700 microg/l for CARDIAC M. Both tests are calibrated by the manufacturer. The reaction times of the tests are 12 or 8 minutes, respectively. Method comparisons were performed with 281 heparinized blood samples from patients with suspected acute coronary syndromes. The results obtained with CARDIAC T Quantitative showed a good agreement compared with cardiac troponin T ELISA (r = 0.89; y = 0.93x + 0.02). The method comparison between CARDIAC M and Tina-quant Myoglobin also showed a good agreement between both assays (r = 0.98; y = 0.92x + 1.6). Test lot-to-lot comparisons yielded differences of 2% and 6% for CARDIAC T Quantitative and of 0 to 11% for CARDIAC M. The within-run imprecision with blood samples and control materials was acceptable for CARDIAC T Quantitative (CV 10 to 15%) and good for CARDIAC M (CV 5 to 10%). The between-instrument CV was below 7% for CARDIACT Quantitative and below 5% for CARDIAC M. The cross-reactivity of CARDIAC T Quantitative with skeletal troponin T was approximately 0.003%. No significant analytical interference was detected for any of the assays in investigations with biotin (up to 100 microg/l), hemoglobin (up to 0.125 mmol/l), hematocrit (26 to 52%), bilirubin (up to 340 micromol/l), triglycerides (up to 5.0 mmol/l), and 18 standard drugs. With the Cardiac Reader reliable quantitative results can be easily obtained for both cardiac markers. The system is, therefore, particularly suitable for use in emergency rooms, coronary care units and small hospitals.

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OBJECTIVE: To evaluate the performance of a visual troponin T rapid test in the hands of nontraditionally trained personnel of 2 critical care units in comparison to 3 laboratories. METHODS: Method comparisons of the troponin T rapid test versus cardiac troponin T enzyme-linked immunosorbent assay were performed with 804 samples from 510 patients with suspected acute coronary syndromes. Cross-reactivity with skeletal troponin T was studied up to 5000 microg/L. RESULTS: Laboratories and critical care units obtained comparable results in the analytical cutoff of the test (0.11 and 0. 10 microg/L) and in the diagnostic sensitivities in the detection of acute myocardial infarction (96% and 93% after 8 hours) and of high-risk patients with unstable angina pectoris (100% and 100%). Different percentages of false-positive results (0.2% and 3%) were found, which may reflect different objectives and strategies in these hospital units. The cross-reactivity with skeletal troponin T was less than 0.01%. CONCLUSIONS: The troponin T rapid test gives reliable results not only when used by laboratory personnel experienced in the execution of analytical methods, but also in the hands of nurses and physicians working in clinical units outside the laboratory.

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The test principle and the optimization of the reactive ingredients are described for the one-step dip and-read immunochromatographic FRONTLINE rapid tests for drugs-of-abuse testing in urine samples. In a multicenter evaluation the rapid tests were compared with FPIA and EMIT immunoassays. Discrepant results were further analyzed by gas chromatography-mass spectrometry methods. In the comparison of the cannabinoids rapid tests versus both immunoassays using clinical and forensic urine samples (399 versus FPIA and 755 versus EMIT), sensitivities and specificities were 97% or better for both comparisons. For cocaine, a sensitivity of 100% versus both routine technologies was obtained, whereas the specificity was reduced somewhat to 91% because of some cross-reactivity with metabolites of methadone and of clozapine. Specificity was very high for the cocaine rapid tests (98-100%) when applied to urine samples of persons not in a methadone maintenance program. Sensitivities and specificities for the opiates rapid tests were 99% or better at all sites when compared with the routine methods. In the screening of about 1200 clinical urine samples for cannabinoids, cocaine or opiates misuse only six samples would have stayed undetected by rapid test analyzes. These results show the FRONTLINE assays allow a reliable and immediate screening for drugs of abuse.

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In a multicentre study, we evaluated the analytical and diagnostic performance of the second version of the TROPT rapid test (TROPT 2, CARDIACT in the US). We tested TROPT 2 on 796 blood samples from 487 patients admitted on suspicion of myocardial infarction between 1 and 72 h after onset of symptoms and determined cTnT ELISA and CK MB mass in the corresponding serum samples. Frequency distributions of the results with TROPT 2 showed a detection limit of 0.18 microgram/l (for 50% positive results) as determined by the quantitative cTnT ELISA method. In a total of 796 samples the sensitivities in the detection of myocardial infarction (WHO criteria) 8-12 h after onset of symptoms were highest for cTnT ELISA (98%), followed by the rapid assay and CK MB mass (92%). A subgroup of 87 patients was primarily classified by the WHO criteria for definite infarction. Based on the maximum values within each patient time-series, diagnostic sensitivities for infarction were 100% for TROPT2, cTnT ELISA and CK MB mass. The corresponding specificities were 90%, 82% and 100%, respectively. After reclassification summarizing all cases of myocardial damage (acute and subacute myocardial infarctions and minor myocardial damage) the sensitivities were 87% (TROPT2), 100% (cTnT ELISA) and 71% (CK MB mass). The specificities of all three markers were 100%. Over 50% of all cases of minor myocardial damage were detected by TROPT 2. The clinical evaluation showed that the diagnostic performance of TROPT 2 is only slightly lower than that of cTnT ELISA.

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In a multicentre study we assessed the analytical and diagnostic performance of a rapid test (TROPT rapid test, Boehringer Mannheim; in the USA: CARDIACT) for cardiac troponin T compared to quantitative troponin T ELISA and creatine kinase-MB mass determinations. The rapid test requires 150 microliters of heparinized or EDTA whole blood; serum is not suitable. Interference testing with biotin, haemoglobin and 27 standard drugs yielded no significant influence in the physiological range. Skeletal muscle troponin T concentrations > or = 40 micrograms/l gave positive results with the rapid test. We used the rapid test for 369 samples from 203 patients with suspected acute coronary syndromes and compared the results to troponin T ELISA and creatine kinase-MB mass. 90 patients (44%) were primarily classified as having myocardial infarction by the WHO criteria. Twenty-two (20%) of the 113 non-myocardial infarction patients were unstable angina pectoris cases showing increased troponin T ELISA but not increased creatine kinase-MB mass values. Consequently, these were classified as minor myocardial damage cases. The rapid test was positive in 99% of all samples with a troponin T ELISA value > or = 0.30 micrograms/l and negative in 95 to 96% of all samples below this value. Diagnostic sensitivities for the detection of acute myocardial infarction within the first 12 hours after onset of pain were the same, 90%, for the rapid test, troponin T ELISA and creatine kinase-MB mass. After 48 hours, diagnostic sensitivity of creatine kinase-MB mass sharply decreased whereas that of the troponin T assays remained close to 100% beyond 72 hours after onset of symptoms. Diagnostic specificities for acute myocardial infarction (WHO) of all markers remained between 80 and 100% over this time. The diagnostic sensitivity of the rapid test for the detection of high risk unstable angina pectoris patients with minor myocardial damage was nearly the same as for troponin T ELISA. A major advantage of the rapid test is the ease of use and 20 minute turn around time. This facilitates the detection of increased troponin T at alternate sites.

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The analytical performance of the new capillary blood prothrombin time monitoring system CoaguChek was examined in a multicenter evaluation at six hospitals. The coefficients of variation of the INR obtained in the CoaguChek imprecision study were approximately 7% in the control plasma provided (within-run and day-to-day) and 4% in blood (within-run). The prothrombin times were ascertained in capillary blood (CoaguChek PT Test) and citrated venous plasma (Hepato Quick, Thromborel S) from 359 patients under oral anticoagulation therapy with phenprocoumon, acenocoumarin or warfarin. The agreement with the test results obtained with the comparison methods was acceptable versus Hepato Quick assay (n = 359; y = 1.23 x -0.49, r = 0.888) and good versus Thromborel S method (n = 359; y = 1.09 x -0.28, r = 0.895). A simplified assessment of all test results (n = 795) in a nine-field comparison table showed a concordance with the comparison methods of more than 80 (Hepato Quick: 81%, Thromborel S: 83%). The concordance between Hepato-Quick and Thromborel S was slightly higher (88%). Its good analytical performance and convenient handling recommend the CoaguChek system as a suitable system for decentralized prothrombin time testing.

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We describe the construction, the reaction principle and the performance of Reflotron K+, a new Reflotron test for the quantitative determination of potassium in serum and heparinized plasma. The reaction principle is based on the introduction of the potassium cation via valinomycin into a non-polar phase; the accompanying loss of protons from the non-polar phase is detected by the colour change of a pH indicator. The multicentre evaluation of the reagent carrier system showed in median CVs of < 0.9% (within-series in heparinized plasmas) and 1.3% (run-to-run in control sera). The recovery in control sera was +/- 4% for seven laboratories. In the method comparison with flame emission spectrometry, using sera and heparinized plasma samples, regression analysis yielded correlations with slopes of 1.00 +/- 0.04 (median slope 1.005) and negligible intercepts. The reagent carrier system showed a linear response in the measuring range 2-12 mmol/l. Bilirubin (up to 513 mumol/l), triacylglycerols (up to 5,7 mmol/l), sodium (135-189 mmol/l) and ammonium ions (up to 590 mumol/l) did not interfere with the test. Comparison with the results from flame atomic emission spectrometry shows that the recoveries of Reflotron K+ and the direct potentiometric method are slightly and similarly influenced by total protein. With a panel of 28 drugs tested, no interference could be detected. Reflotron K+ provides a precise and reliable procedure for the measurement of potassium in serum and heparinized plasma.

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In the Reflotron Amylase dry-reagent carrier system (Boehringer Mannheim GmbH) a new substrate is used for determining total amylase (EC 3.2.1.1) activity:indolyl-alpha-D-maltoheptaoside. The procedure shows low imprecision (median CV less than 3.2%), and results for sera, plasma, and capillary and venous blood (y) correlate well with those of a conventional alpha-amylase method involving p-nitrophenyl (PNP)-maltoheptaoside substrate (x) (for 209 blood samples: y = 0.981x + 9.7; r = 0.994). Correlation was also excellent with a method involving maltotetraose as substrate (r = 0.987). Attachment of an indoxyl residue rather than a PNP group to the maltoheptaoside did not affect the substrate response to pancreatic or salivary isoenzyme activity. Therefore, the relative proportion of these isoenzymes did not affect the correlation between the Reflotron Amylase reagent carrier and the alpha-amylase PNP-maltoheptaoside method. With a reaction time of less than 3 min, this system is especially suitable for amylase determination in situations where a prompt result is required.

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