Abstract
Urinary tract infection is a commonly encountered problem in clinical practice. Diagnosis is usually reached by considering compatible symptoms, microscopy and culture of urine samples. We carried out a retrospective study of records of patients established to have urinary tract infection at King Khalid University Hospital, Riyadh. The results showed the infection predominantly occurring in female patients comprising 74.2 per cent. The overall positivities/positive predictive values for urine nitrites were 49.7per cent and 95.4 versus 5.5 per cent and 2.3 for gram-negative and gram-positive organisms respectively. The proportional significance of nitrite positivities for both gram-negative organisms versus gram-positive organisms and yeast were 0.50 versus 0.06 and 0.50 versus 0.09 respectively (p value<0.001) while the difference between gram-positive organisms and yeast 0.06 versus 0.09 was insignificant (p>0.50). We therefore recommend that the presence of positive nitrites predict the likelihood of gram-negative as a causative agent in urinary tract infections. However, nitrites should not be used as screening test in view of the low sensitivity across all types of organisms.