Test Code: 39165

Clinical use

• Detect chronic kidney disease (CKD) in adults
• Monitor CKD therapy and/or progression in adults

Clinical background

An estimated 37 million people in the United States have CKD, but most (about 90%) are unaware that they are affected.1 High-risk populations (% untested) include individuals with hypertension (94%), diabetes (61%), or both (60%).2 In addition, individuals who are obese, are of older age (≥65 years), had previous kidney damage, or have a family history of CKD are also at higher risk of having CKD.1 Overall, CKD awareness is suboptimal and has not improved over the last 2 decades.3

Identifying and treating CKD at earlier stages may prevent or delay adverse outcomes. Using the Kidney Failure Risk equation (KidneyFailureRisk.com), patients categorized as having high risk for end-stage renal disease are >10 times as likely as low-risk patients to have kidney failure within 5 years, yet about half remain unaware of their CKD.3 Knowledge of the presence of CKD may guide lifestyle changes that mitigate risk factors that are common to kidney- and cardiac-related disease.3 The risk of cardiovascular events and death increases with increasing CKD severity.2 Thus, monitoring and managing patients with CKD are also important for decreasing morbidity and mortality.4

CKD is defined based on the presence of an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 for >3 months, evidence of kidney damage for >3 months, or both.5 Evidence of kidney damage is assessed by detecting albuminuria, which involves measuring a urine albumin-creatinine ratio ≥30 mg/g (μg/mg).5 Albuminuria is one of the first signs of renal disease and, if left untreated, may progress to overt renal failure.5,6 A study based on data from the 2013 to 2016 National Health and Nutrition Examination Survey (NHANES) showed that only 8% of people with an eGFR <60 mL/min/1.73 m2 knew they had CKD.7 For those with the same eGFR and albuminuria, only 28% were aware they had CKD.7

Albuminuria is independently associated with an increased risk of cardiovascular events and an increased mortality.6 In patients with diabetes, early detection of albuminuria, followed by improvement of glucose control and treatment with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, may slow or prevent progression to end-stage renal disease.6

Quest Diagnostics offers the Kidney Profile (test code 39165) to assist in CKD staging based on eGFR and urine albumin-creatinine ratio. The National Kidney Foundation recommends using the test results to identify CKD in at-risk patients (listed below) and to monitor disease progression.2 eGFR and albumin-creatinine ratio are also important independent risk predictors of major adverse cardiovascular events (myocardial infarction or stroke).8

Interpretive information

The Figure demonstrates the use of eGFR and urine albumin-creatinine ratio for predicting CKD prognosis and for managing patients with CKD.

Figure. Frequency of Monitoring Chronic Kidney Disease Based on Risk of Disease Progression Assessed Using eGFR and Urine Albumin-Creatinine Ratio (Kidney Profile, test code 39165)

 

Exercise within 24 hours of collection, infection, fever, congestive heart failure, marked hyperglycemia, marked hypertension, pyuria, and hematuria may cause elevated urinary albumin levels. Results should be interpreted in conjunction with other laboratory and clinical findings.

References

1. Centers for Disease Control and Prevention. Chronic kidney disease in the United States, 2021. Updated March 4, 2021. Accessed May 12, 2022. https://www.cdc.gov/kidneydisease/pdf/Chronic-Kidney-Disease-in-the-US-2021-h.pdf
2. National Kidney Foundation Laboratory Engagement Advisory Group. Laboratory engagement plan: transforming kidney disease detection. Updated February 2018. Accessed May 12, 2022. https://www.ascp.org/content/docs/default-source/get-involved-pdfs/istp-ckd/laboratory-engagement-plan.pdf
3. Chu CD, McCulloch CE, Banerjee T, et al. CKD awareness among US adults by future risk of kidney failure. Am J Kidney Dis. 2020;76(2):174-183. doi:10.1053/j.ajkd.2020.01.007
4. Vassalotti JA, Centor R, Turner BJ, et al. Practical approach to detection and management of chronic kidney disease for the primary care clinician. Am J Med. 2016;129(2):153-162.e7. doi:10.1016/j.amjmed.2015.08.025
5. Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2012 clinical practice guideline for the evaluation and management of chronic kidney disease. Kidney Int Suppl. 2013;3(1):1-150.
6. American Diabetes Association. 11. Chronic kidney disease and risk management: standards of medical care in diabetes—2022. Diabetes Care. 2022;45(suppl 1):S175-S184. doi:10.2337/dc22-S011
7. United States Renal Data System. 2018 USRDS Annual Data Report: Epidemiology of Kidney Disease in the United States. National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health. Accessed May 12, 2022. https://www.usrds.org/annual-data-report/previous-adrs/
8. Currie CJ, Berni ER, Berni TR, et al. Major adverse cardiovascular events in people with chronic kidney disease in relation to disease severity and diabetes status. PLoS One. 2019;14(8):e0221044. doi:10.1371/journal.pone.0221044
9. Delgado C, Baweja M, Crews DC, et al. A unifying approach for GFR estimation: recommendations of the NKF-ASN Task Force on reassessing the inclusion of race in diagnosing kidney disease. Am J Kidney Dis. 2022;79(2):268-288.e1 doi:10.1053/j.ajkd.2021.08.003
10. Myers GL, Miller WG, Coresh J, et al. Recommendations for improving serum creatinine measurement: a report from the Laboratory Working Group of the National Kidney Disease Education Program. Clin Chem. 2006;52(1):5-18. doi:10.1373/clinchem.2005.0525144
    
    

Content reviewed 06/2022

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