First line treatment in hypertension.

urological investigation and monitored uneventfully after a non-invasive nephrological assessment.After a mean follow up of 3-5 years only two had developed non-glomerular haematuria after repeated urine microscopy, both of whom were later found to have underlying urothelial disease.Despite its initial promise this technique has not been widely adopted in the United Kingdom,2 probably because of concern about interobserver variations in reporting microscopy results.23Interest has instead been directed towards using automated haematological analysers to assess urinary erythrocyte morphology,24 25 but the inaccuracy of this technique at low red cell counts may limit its practical application.26In our experience variations in reporting micro- scopy findings may be reduced with a more precise classifi- cation of urinary red cell variants (unpublished observations) and the accuracy of automated analysers substantially enhanced by using simple modifications.27Over the next few years these newer techniques may well achieve acceptable standards of accuracy and reproducibility for routine use and, with the adoption of widespread urinary screening by general practitioners, are likely to have an impact on the practice of both nephrologists and urologists.Until then further investigation ofpatients with asymptomatic dipstick haematuria, even in the absence of confirmatory microscopy or other markers of underlying disease, is recommended.We also suggest a standard non-invasive nephrological assessment and long term follow up to detect potentially progressive renal disease in those patients with urologically unexplained blood loss.