Don't use urine microscopy to confirm microscopic haematuria

doi:10.1136/bmj.b2629

Published 29 June 2009, doi:10.1136/bmj.b2629
Cite this as: BMJ 2009;338:b2629

Letters

Haematuria

Don’t use urine microscopy to confirm microscopic haematuria

The first 150 words of the full text of this article appear below.

The presence of urinary myoglobin will generate occasional falsepositive results when using dipstick urine analysis for diagnosingmicroscopic haematuria. However, it is poor practice to attemptto confirm the presence of red cells by urine microscopy.¹ Urinaryred cells are lysed in acidic urine or after prolonged storage,and laboratory error is common in urine microscopy; the resultof adopting such a policy is to convert a small false positiverate into a large false negative rate. If investigation or follow-upis contemplated, it is far better to omit this step and followthe advice of the UK Renal Association and the guideline fromthe National Institute for Health and Clinical Excellence (NICE).²³

Whether it is valuable to investigate a patient under 40 presentingwith microscopic haematuria who does not have hypertension,alert symptoms, proteinuria, or abnormal renal function is debatable.The fact that such patients are inappropriately (and . . . [Full text of this article]

Peter A Andrews, consultant nephrologist¹

¹ South West Thames Renal and Transplantation Centre, St Helier Hospital, Carshalton, Surrey SM5 1AA

peter.andrews@esth.nhs.uk