Guidelines have been issued by many professional organizations for detecting, monitoring, and treating chronic kidney disease (CKD). However, there are several physiologic and measurement limitations affecting the utilization of laboratory results to assess CKD, and it is essential for laboratory medicine professionals to understand them. Diabetes impacts 29.1 million people in the U.S. alone and is the seventh leading cause of death. It is listed as the primary cause of kidney failure in 44% of all new cases.

As Andrew Narva, MD, explains it, “a diagnosis of kidney disease has great implications for a patient receiving that diagnosis and it is critical that clinicians and the clinical lab community understand both the utility and the limitations of these tests in order to serve the needs of the patients.” Narva will speak at a symposium this afternoon, “Diabetic Nephropathy: Where Are We Now?” He will be joined by Greg Miller, PhD and Katherine Tuttle, MD.

Creatinine and creatinine-based estimated glomerular filtration rate (eGFR) equations remain the most popular tests for assessing kidney function. Due to known limitations of creatinine, the most recent guidelines have added urine albumin and cystatin C for classifying the severity of CKD as an aid to treatment recommendations.

Miller will be discussing issues around cystatin C. He points out that cystatin C “can be a useful complement to creatinine-based equations to estimate GFR, but its use is limited because the assay is not yet standardized in the U.S.,” he says. “Urine albumin is commonly measured, but also non-standardized, leading to misclassification of risk near threshold values.”

These are important measurement limitations that have now become the focus of a collaborative standardization effort between the National Institutes of Health’s National Kidney Disease Education Program and the laboratory medicine community.

In addition to cystatin C, speakers also will cover physiologic and analytic strengths and limitationS of creatinine, urine albumin, and more. These limitations are important because all biomarkers are impacted by physiologic limitations that include various influences on production and elimination. This leads to uncertainty in applying population-derived decision values to an individual patient. Laboratory medicine professionals must clearly communicate these factors to clinicians in order to avoid misinterpretation of results. The successful implementation of routine reporting of estimated glomerular filtration rate requires the laboratory community to play an active role in helping clinicians understand the benefits and limitations of this tool when diagnosing and monitoring patients.

Interested in finding out how you should be reporting eGFR and what information you should be communicating to clinicians? Learn more about interpretation of laboratory results for diabetic nephropathy at today’s symposium, 2:30 p.m. to 5:00 p.m.