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Rob T P Jansen

Publications and source records attributed to Rob T P Jansen.

2 recordsLinked to original sources

The EC4 register of European clinical chemists and EC4 activities.

The freedom of movement of people and goods within the European Union (EU) has a large impact for the member states. Particularly within health care it is important to recognize, or if necessary obtain, an adequate level of the quality of profession and practice, so that citizens know that health care is offered in their country at a level comparable to other countries. The importance of recognition also applies to laboratory medicine. European Communities Confederation of Clinical Chemistry (EC4) is the organization of societies for clinical chemistry and laboratory medicine in the EU. In Europe, health care develops in the direction where patients are treated in a health care chain environment. In this chain, patients move quickly from primary health institutes to secondary and tertiary institutes, and vice versa. This situation involves many health care workers including several laboratories. Diagnosis and therapy are now 'core business' of health care. Medical laboratories play an essential role in this. The broad spectrum of medical laboratory investigations make consultancy of medical laboratory specialists ever more important. The quality of both professionals and laboratories, as well as continuity of laboratory data within and between laboratories, are of utmost importance.EC4 is active in giving support to attain such quality. In most countries, this is the case at present. EC4 plays a central role in the Coordination of Automatic Recognition of Equivalence of Standards (CARE), if such a level exists or is achieved. Such CARE is focussed at three levels, the profession, quality of laboratories and calibration of laboratory data. The EC4 Register of European Clinical Chemists is open for colleagues educated in (bio)chemistry, pharmacy, biology as well as medicine, and trained according to the EC4 Syllabus. Equivalence of standards has been granted to national training schemes of 13 European Union countries. Since its opening in 1998, the number of applicants is growing steadily and quickly, reaching 1225 in May 2001.EC4 has published essential criteria for quality systems of medical laboratories, which formed the basis for a ISO draft international standard regarding quality and competence of medical laboratories.EC4 stimulates projects like the Calibration 2000 project in the Netherlands which focus on continuity of laboratory data, within-as well as between-laboratories.

Calibration↗

Internal quality control system for non-stationary, non-ergodic analytical processes based upon exponentially weighted estimation of process means and process standard deviation.

The analytical processes in clinical laboratories should be considered to be non-stationary, non-ergodic and probably non-stochastic processes. Both the process mean and the process standard deviation vary. The variation can be different at different levels of concentration. This behavior is shown in five examples of different analytical systems: alkaline phosphatase on the Hitachi 911 analyzer (Roche), vitamin B12 on the Access analyzer (Beckman), prothrombin time and activated partial thromboplastin time on the STA Compact analyzer (Roche) and PO2 on the ABL 520 analyzer (Radiometer). A model is proposed to assess the status of a process. An exponentially weighted moving average and standard deviation was used to estimate process mean and standard deviation. Process means were estimated overall and for each control level. The process standard deviation was estimated in terms of within-run standard deviation. Limits were defined in accordance with state of the art- or biological variance-derived cut-offs. The examples given are real, not simulated, data. Individual control sample results were normalized to a target value and target standard deviation. The normalized values were used in the exponentially weighted algorithm. The weighting factor was based on a process time constant, which was estimated from the period between two calibration or maintenance procedures. The proposed system was compared with Westgard rules. The Westgard rules perform well, despite the underlying presumption of ergodicity. This is mainly caused by the introduction of the starting rule of 12s, which proves essential to prevent a large number of rule violations. The probability of reporting a test result with an analytical error that exceeds the total allowable error was calculated for the proposed system as well as for the Westgard rules. The proposed method performed better. The proposed algorithm was implemented in a computer program running on computers to which the analyzers were linked on-line. Each result was evaluated on-line, and a limit violation was immediately reported. The system has performed satisfactorily in our laboratory for ten analyzers for over 1 year.

Biometry↗