Houben PHH, Van der Weijden T, Van Bokhoven MA, Droog AEJ, Winkens R, Grol RPTM. How general practitioners interpret laboratory test results; a qualitative interview study. Huisarts Wet 2005;48(7):326-32.
Introduction Laboratory results can be interpreted using calculations with pre-test probability, sensitivity and specificity. However clinicians do not use these calculations explicitly in daily practice. Informal methods predominate, but what they are and how they work is unknown. Our aim was to explore how GPs interpret laboratory results.
Methods We held a qualitative semi-structured interviews with 21 GPs regarding the last 10 laboratory results they had received. Interviews were transcribed verbatim and coded independently by two researchers. Concepts and hypothesis emerged during analysis and were revised and refined during continued analysis.
Results The concept of laboratory result and diagnostic hypothesis each consist of several dimensions. The dimensions interact and are constantly involved in the interpretation of results. Some examples of important dimensions include: one single test result as well as groups of tests are not interpreted dichotomously but on a continuous scale; laboratory test reference values can be regarded as too strict for patients in a GP population; GPs often do not have a specific diagnosis, their aim being to exclude clues pointing to some disorder; GPs estimate the probability of a disorder in qualitative terminology. The dimensions interact with the most particular effect: laboratory findings that fall outside reference values cause no problems if the GP expects no disorder.
Conclusion The interpretation of laboratory results is a complex interaction of dimensions that can be distinguished in the laboratory result and the diagnostic hypothesis. Those designing interventions to improve the use of laboratory tests should be aware of the way in which GPs actually interpret results.