Significance of microhaematuria in young adults.

The medical records of 1000 asymptomatic male air force personnel were examined retrospectively for the results of 15 yearly examinations of urinary sediment. The study covered the period 1968-82, beginning with the subjects aged 18-33 years. The cumulative incidence of two to four or more red blood cells per high power field found at one or more examinations was 38.7% after an average of 12.2 yearly examinations per person. In 161 subjects two to four or more red blood cells per high power field were found at two or more yearly examinations within a five year period. Intravenous pyelography in 58 cases disclosed asymptomatic nephrolithiasis in six. Cystoscopy performed in 11 cases identified one patient with urethritis, one with a vesical calculus, and one with transitional cell carcinoma of the bladder. Two years before diagnosis the patient with carcinoma had had a single transient finding of 10-12 red blood cells per high power field which was not investigated further. Cystoscopy was performed after an episode of macroscopic haematuria. Renal biopsy in one subject with recurrent microhaematuria and trace proteinuria disclosed focal glomerulonephritis. None of the remaining subjects with microhaematuria developed hypertension or proteinuria, and at the end of the study period all were active and free of urinary symptoms. The observed cumulative incidence of urological neoplasms at 15 years (0.1%) was consistent with that expected in Israeli men aged 18-40 (0.09%). Hence microhaematuria detected during a screening examination probably should not be regarded as a specific sign of a significant lesion and does not of itself warrant urological investigation in adults aged 40 or less.