ABSTRACT
The prevalence of low serum urea nitrogen concentrations (<6 mg/dL) in our patient population was 3.8% (452 per 11,911 determinations), representing 372 individual cases. Of these, 323 of the patients' charts were located, reviewed, and classified into disease groups. Malignant tumor was found in 25.1% of the 323 patients, the remaining patients without malignant tumor had various clinical conditions; pregnancy (19.5%), infectious diseases (12.1%), trauma (10.2%), cerebrovascular accident (6.2%), hepatopathy (5.3%), and miscellaneous conditions (21.6%). The prevalence in female and young aged patients under 5 years was considered due to the lower reference range in these groups than in that of female adult groups, and moreover pregnancy in another superimposing factor in the former group. In regards to the causes of this condition, our study corresponded well to the textbook cited etiology of the low serum nitrogen concentration, although malnutrition and hepatopathy were inverted in their incidental order. We postulated, through the present study, that the low serum urea nitrogen concentration is not pathognomonic findings to suggest specific disease or conditions, but rather to reflect patient's general conditions such as hydration, nutrition, or administration of certain drugs.