Integration between point-of-care cardiac markers in an emergency/cardiology department and the central laboratory: methodological and preliminary clinical evaluation

A systematic evaluation of immunoassay point-of-care testing to define impact on patients' outcomes

Background Point-of-care testing has been developed to provide rapid test results. Most published studies focus on analytical performance, neglecting its impact on patient outcomes. Objective To review the analytical performance and accuracy of point-of-care testing specifically planned for immunoassay and to evaluate the impact of faster results on patient management. Methods A search of electronic databases for studies reporting immunoassay results obtained in both point-of-care testing and central laboratory scenarios was performed. Data were extracted concerning the study details, and the methodological quality was assessed. The analytical characteristics and diagnostic accuracy of six points-of-care testing: troponin, procalcitonin, parathyroid hormone, brain natriuretic peptide, C-reactive protein and neutrophil gelatinase-associated lipocalin were evaluated. Results A total of 116 scientific papers were analysed. Studies measuring procalcitonin, parathyroid hormone and neutrophil gelatinase-associated lipocalin reported a limited impact on diagnostic decisions. Seven studies measuring C-reactive protein claimed a significant reduction of antibiotic prescription. Several authors evaluated brain natriuretic peptide or troponin reporting faster decision-making without any improvement in clinical outcome. Forty-four per cent of studies reported analytical data, showing satisfactory correlations between results obtained through point-of-care testing and central laboratory setting. Half of studies defined the diagnostic accuracy of point-of-care testing as acceptable for troponin (median sensitivity and specificity: 74% and 94%, respectively), brain natriuretic peptide (median sensitivity and specificity: 82% and 88%, respectively) and C-reactive protein (median sensitivity and specificity 85%). Conclusions Point-of-care testing immunoassay results seem to be reliable and accurate for troponin, brain natriuretic peptide and C-reactive protein. The satisfactory analytical performance, together with an excellent practicability, suggests that it could be a consistent tool in clinical practice, but data are lacking regarding the patient outcomes.

Point-of-care testing: where is the evidence? A systematic survey

Point-of-care testing (POCT) has had rapid technological development and their use is widespread in clinical laboratories to assure reduction of turn-around-time and rapid patient management in some clinical settings where it is important to make quick decisions. Until now the papers published about the POCT have focused on the reliability of the technology used and their analytical accuracy. We aim to perform a systematic survey of the evidence of POCT efficacy focused on clinical outcomes, selecting POCT denoted special analytes characterized by possible high clinical impact. We searched in Medline and Embase. Two independent reviewers assessed the eligibility, extracted study details and assessed the methodological quality of studies. We analyzed 84 studies for five POCT instruments: neonatal bilirubin, procalcitonin, intra-operative parathyroid hormone, troponin and blood gas analysis. Studies were at high risk of bias. Most of the papers (50%) were studies of correlation between the results obtained by using POCT instruments and those obtained by using laboratory instruments. These data showed a satisfactory correlation between methods when similar analytical reactions were used. Only 13% of the studies evaluated the impact of POCT on clinical practice. POCT decreases the time elapsed for making decisions on patient management but the clinical outcomes have never been adequately evaluated. Our work shows that, although POCT has the potential to provide beneficial patient outcome, further studies may be required, especially for defining its real utility on clinical decision making.

Laboratory testing during critical care transport: point-of-care testing in air ambulances

Air and ground transport are used for prehospital transport of patients in acute life-threatening situations, and increasingly, critically ill patients undergo interhospital transportation. Results from clinical studies suggest that critical tests performed during the transport of critically ill patients presents a potential opportunity to improve patient care. Our project was to identify, according to the recommendations published at this time, a model of point-of-care testing (POCT) (arterial blood gases analysis and glucose, sodium, potassium, ionized calcium, hematocrit/hemoglobin measurements) in air ambulances. In order to identify the key internal and external factors that are important to achieving our objective, an analysis of the Strengths, Weaknesses, Opportunities, and Threats (SWOT analysis) was incorporated into our planning model prior to starting the project. To allow the entire POCT process (pre-, intra-, and post-analytic steps) to be under the control of the reference laboratory, an experimental model of information technology was applied. Real-time results during transport of critically ill patients must be considered to be an integral part of the patient care process and excellent channels of communication are needed between the intensive care units, emergency medical services and laboratories. With technological and computer advances, POCT during critical care transport will certainly increase in the future: this will be a challenge from a laboratory and clinical context.

Usefulness of detectable levels of troponin, below the 99th percentile of the normal range, as a clue to the presence of underlying coronary artery disease

The aim of the study was to evaluate whether markers of myocardial injury and ischemia are helpful in detecting coronary artery disease (CAD) in patients with stable angina. Venous blood was obtained before and after a bicycle exercise test in 47 outpatients with suspected CAD for measurement of cardiac troponin I (cTnI), heart-type fatty acid binding protein, and glycogen phosphorylase BB. Patients with a coronary artery stenosis >/=70% in diameter (n = 33) were compared with patients with coronary narrowing <50% (controls, n = 14). None of the markers increased after bicycle exercise testing. cTnI measured before and after exercise was higher in the CAD group than in controls (p <0.001). The area under the curve for diagnosis was greater when the cTnI value was detectable than with stress testing alone. In conclusion, baseline cTnI was of value in detecting CAD and also during follow-up in predicting the need for further revascularization.

Point-of-care testing in the cardiovascular operating theatre

Point-of-care testing (POCT) remains under scrutiny by healthcare professionals because of its ill-tried, young history. POCT methods are being developed by a few major equipment companies based on rapid progress in informatics and nanotechnology. Issues as POCT quality control, comparability with standard laboratory procedures, standardisation, traceability and round robin testing are being left to hospitals. As a result, the clinical and operational benefits of POCT were first evident for patients on the operating table. For the management of cardiovascular surgery patients, POCT technology is an indispensable aid. Improvement of the technology has meant that clinical laboratory pathologists now recognise the need for POCT beyond their high-throughput areas.

Clin Chem Lab Med 2006;44:1060–5.

Proteomic approach to the diagnosis of acute coronary syndrome: Preliminary results

BACKGROUND

Cardiac multimarker strategy is recommended by the IFCC, ESC and the ACC for an early risk stratification in non-ST-segment elevation (NSTE) ECG patients with chest pain. A new approach, based on protein biochip array technology, performs simultaneously: cTnI, CK-MB, myoglobin, CAIII, GFBB and FABP using a single chip.

METHODS

We evaluated the analytical performance of the Randox-Evidence Investigator -biochip cardiac panel according to IFCC recommendations and NCCLS guidelines; a preliminary clinical evaluation was carried out on chest pain NSTE ECG patients, to evaluate the accuracy of the multimarker approach in an early diagnosis of AMI, related to the final diagnosis (ACC/ESC criteria).

RESULTS

Troponin, CK-MB and FABP methods provide reproducible within-run and between-day results (total % CVs from 5.9% to 9.7%), and myoglobin and CAIII methods showed the total % CVs from 16.4% to 25.8%. Our preliminary clinical data suggests that FABP had a better diagnostic performance (sensibility = 100%) than myoglobin (sensibility = 75%) to detect AMI in the first hours after the onset of the chest pain and myoglobin/CAIII ratio (specificity = 92.9%) improved the myoglobin specificity.

CONCLUSIONS

Cardiac markers have different diagnostic roles and, in this contest, biochip technology could be an interesting approach supporting clinical expectations.