Introduction: A reference interval is very important in the practice of laboratory medicine as medical personnel depend on this to make diagnosis, treat and monitor patients. An accurately determined reference interval of a population can be said to be the first step to patient care. More so, reference intervals need to be periodically reviewed due to population dynamics.

Aim: To determine the current reference interval of urea and to compare same with the previously determined interval here and that presently in use in our laboratory.

Methods: Urea results of patients who were non diabetic, non-hypertensive and had no cardiac or renal disorders were obtained for a period of three months. These results were ranked and the mean determined. The nonparametric method was used to determine the reference interval from the data.

Result: The mean urea result was 2.6mmol/l and the reference interval was 1.2- 3.6mmol/l

Conclusion: The reference interval so generated (1.2-3.6mmol/l) is clinically about the same with that generated about twenty years ago (1.2- 3.9mmol/l) and both are significantly different from that in use in our laboratory (2.4-6.2mmol/l). The use of this current reference interval will therefore improve interpretation of urea results in our area.

Keywords: Non Parametric, Reference Interval, Diacetyl monoxine.

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Dr Frederick Igila Allison

Department of Chemical Pathology, University of Port Harcourt

Port Harcourt, River state, Nigeria