Where now for proteinuria testing in chronic kidney disease?: Good evidence can clarify a potentially confusing message.

Abstract

Although the value of testing for proteinuria may be undisputed and understood by nephrologists and diabetologists, the lack of clarity about the rationale for testing and the optimal way of doing so in primary care has caused confusion for many practitioners.1 Issues such as variation in proteinuria definition, laboratory measurement, and reporting methods, along with conflicting messages about who, how, and when to test, have led to uncertainty and under-testing.1,2 There have been long-standing debates about the use of various dipsticks, the role of proteinuria in urinary tract infection, the use of urinary protein:creatinine ratio (PCR) versus albumin:creatinine ratio (ACR), and the number of tests needed for identification versus quantification of proteinuria. Reporting variations include some laboratories using non-numeric results such as ‘ratio too low to calculate’ making visualisation of results and accurate audit of ACR testing challenging for busy practitioners. Urinary dipsticks have important limitations in terms of their accuracy in detecting and quantifying albuminuria.3 In this context, GPs and other clinicians could be forgiven for being uncertain about the clinical utility of its identification. Chronic kidney disease (CKD) has been included in the Quality and Outcomes Framework (QOF) since 2006–2007, and, from 2009–2010, included a proteinuria indicator (‘The percentage of patients on the CKD register whose notes have a record of a urine albumin:creatinine ratio [or protein:creatinine ratio] test in the preceding 12 months’). Currently, several CKD indicators are in the process of being ‘retired’, including the one relating to proteinuria testing. This increases the potential for uncertainty about the role of proteinuria testing and is likely to lead to a fall in ACR tests in England, particularly in people without diabetes, unless it is seen as valuable in its own right. It may also serve to reinforce the suggestion that labelling people …