Macroscopy and Microscopy Urinalysis: A Vital Screening Procedure for Urinary Tract Infections (UTIs) in a Hospital in Awka, Nigeria

Abstract

Urine examination has been employed in clinical practice as the most common screening laboratory method for early detection of urinary tract infections (UTIs) or renal disorder. This study was undertaken to ascertain the usefulness of urine macroscopy and microscopy as vital screening procedure for diagnosing UTI among antenatal patients in a teaching hospital in Awka, Nigeria. Freshly voided midstream urine specimens of 269 pregnant women were collected and examined using macroscopic, microscopic and culture methods. The sensitivity, specificity, positive predictive value and negative predictive value of urine colour, and microscopic features were compared with urine culture in diagnosis of UTI. Statistical analysis was done using SPSS and Epi info^® and P-value was set at <0.05 significant level. One hundred and seven specimens showed positive urine cultures. Out of these 107 specimens, 60 (56.1%) also had deviation from normal urine colour and 77(72%) were positive on urine microscopy. Macroscopic examination showed that a significant relationship exists between urine colour and positive urine culture (p=0.0001). The sensitivity and specificity of urine colour with respect to UTI were 56.7% and 67.9% respectively. Urine microscopy revealed that the positive features had a significant relationship with positive urine culture (p= 0.000). Pyuria alone showed the specificity and positive predictive value of 100% each. The sensitivity, specificity, positive predictive value and the negative predictive value of combination of positive microscopic features were 72%, 64.8%, 57.5% and 77.8% respectively. Examination of colours and microscopic features of urine are therefore vital in predicting urinary tract infection.