Research project at the Department of Clinical Chemistry, University of Turku

Information technology and use of patient databases in the clinical evaluation of laboratory data

Purpose of the project:

The aim of the project is to develop methods for the production of clinically useful information from laboratory databases. Well-defined reference values are essential for adequate clinical interpretation of laboratory test results. So far, laboratories have mainly offered only the health-related reference interval to aid in the clinical interpretation of laboratory results. The availability of well-defined data sets in routine laboratory databases makes it possible to produce illness-related reference values and within-subject reference change values as well. This data can be used for the estimation of clinical decision levels. The methods applicable for these purposes have been developed and the reliability and validity of source data studied by comparing the data with that from well defined prospective reference groups.

Main results published so far:

• group-specific reference values from patient databases have been produced
• for analytes used in the diagnosis of pheochromocytoma (Clin Chem 1992;38: 416-20),
• for cardiac enzymes (Eur J Clin Chem Clin Biochem 1994;32: 789-96) and
• for some hematological analytes (Clin Chem 1994;40: 2209-15)
• the clinical reliability of patient discharge databases has been evaluated (Scand J Clin Lab Invest 1995;55, Suppl 222: 69-73)
• reference values produced from unselected hospital patients have been used for constructing quality control limits for the detection of random analytical errors in multichannel hematology analyzers (Am J Clin Pathol 1992;97: 645- 51)
• a statistical method has been developed for the production of reference change limits (Clin Chem 1993;39:2298-2304, Scand J Clin Lab Invest 1995;55, Suppl 222: 37- 41)
• a bin width optimization system has been suggested for illustrative display of data and ROC curves (Clin Chem 1995;41: 766-7)
• the effect of platelet count on serum and plasma potassium has been evaluated using database information from two hospitals (Scand J Clin Lab Invest 1995;55, Suppl 222: 95-100)
• software, GraphROC for Windows, with graphical user interface has been developed for the estimation of basic clinical characteristics of laboratory tests (Scand J Clin Lab Invest 1995;55, Suppl 222: 43- 60)

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