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Title: Η χρήση των αθροιστικών διαγραμμάτων στον εσωτερικό έλεγχο ποιότητας των αναλυτών κλινικής χημείας
Authors: Καρκαλούσος, Πέτρος
Item type: Journal article
Keywords: Εσωτερικός έλεγχος ποιότητας;Αναλυτές;Κλινική χημεία;Internal quality controls;Analyzer;Clinical chemistry;CUSUM technique;Tabular cusum;Decision Limit Cusum;Levey-Jennings
Subjects: Medicine
Issue Date: 6-May-2015
Date of availability: 6-May-2015
Language: Greek
Citation: Καρκαλούσος, Π. (2002) H χρήση των αθροιστικών διαγραμμάτων στον εσωτερικό έλεγχο ποιότητας των αναλυτών κλινικής χημείας. "Εφαρμοσμένη Κλινική Μικροβιολογία και Εργαστηριακή Διαγνωστική", 7 (4), σ. 181-191.
Journal: Εφαρμοσμένη Κλινική Μικροβιολογία και Εργαστηριακή Διαγνωστική
Type of Journal: With a review process (peer review)
Table of contents: In the last thirty years the rapid development of automatic analyzers have been combined with the development of statistical quality control methods. These methods improved the precision and repeatability of the tests and they reduced random and systematic errors. The imprecision’s quality methods transported to the laboratories of clinical chemistry from the chemical industry. The chart control of the American chemists Levey and Jennings is the most accepted method of them. It is based on the principles of Gauss distribution of the daily control values. An other group of internal quality control methods is based on the calculation of cumulative sums (Cusum) of the differences of the daily control values from the mean of the control limits. Τhree cusum methods exists: the simple Cusum diagram, the Tabular Cusum and the Decision Limit Cusum. All methods are specifically efficient on finding small systematic errors, which most of times are invisible in Levey Jennings diagrams. First duty of the method’s users is to define the value beyond which the tests will be considered as “out of limits”. The value limit (symbol µ1) has been chosen as medically important. The number µ1 estimates the variable K. It is the distance between the limit µ1 and the mean–target value of the method. It is measured in standards deviations. This variable effects the starting and the calculation of the cumulative sum with a different way in both methods (Tabular Cusum and Decision Limit). The upper and lower limits of the methods (H) are calculated from variable K and some special statistical methods. The violation of H reveals the presence of systematic error. In this case the exam has not good performance. The most interesting Cusum diagram is Decision Limit Cusum because it can be plotted on the same diagram with Levey-Jennings.
Access scheme: Publicly accessible
License: Αναφορά Δημιουργού-Μη Εμπορική Χρήση-Όχι Παράγωγα Έργα 3.0 Ηνωμένες Πολιτείες
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