By: Adeera Levin, MD, FRCPC Nancy Craven, MD, CCFP
ACR has value
Issue: BCMJ,
vol. 49, No. 0, March 2007,
Pages 57-58 Letters
In response to the article, “Does the albumin:creatinine ratio lack clinical utility in predicting microalbuminuria?” in the October 2006 issue of BCMJ (48[8]:399-403), we wish to present some clarification and a different view of the value of the urine ACR test.
Although the authors acknowledge that “ACR has been shown to be convenient, cost-effective, and efficient in screening patients for microalbuminuria when compared with 24-hour urine collections,” they conclude that “we have demonstrated the inadequacy of the albumin:creatinine ratio as an alternative to the 24-hour albumin excretion rate in diagnosing microalbuminuria.” In our opinion, this conclusion is not warranted.
The recognized standards in North America for diagnosis and management of chronic kidney disease (CKD) follow the National Kidney Foundation Disease Outcome Quality Initiative (KDOQI) guidelines. BC Health and the BCMA Guidelines and Protocols Advisory Committee used these guidelines and many other evidence-based resources to determine that ACR should be one of the tests used to screen for CKD. A key point in these guidelines is that a single test result is not adequate to make a diagnosis, but rather an abnormal value should be persistent (i.e., present for > 3 months). Following this recommendation, it would be unlikely that someone would be started on lifelong medication erroneously as claimed in the article.
With regard to 24-hour urine collections, numerous reports have discussed the inaccuracy of such collections unless done under strict supervision. From a practical point of view, most clinicians and labs would probably reject the idea that everyone needing screening for microalbuminuria should have a 24-hour urine collection.
With the increase in hypertension and diabetes worldwide, an easy and useful screening test for microalbumin is essential. Many studies have concluded that the random urine ACR is the test that should be used.
| — | Adeera Levin, MD, FRCPC Director, BC Renal Agency |
| — | Nancy Craven, MD, CCFP Clinical Associate, VIHA Renal Services |