4363.0.55.001 - Australian Health Survey: Users' Guide, 2011-13  
Latest ISSUE Released at 11:30 AM (CANBERRA TIME) 11/12/2013   
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ALBUMIN/CREATININE RATIO (ACR)

Definition

The Albumin/Creatinine ratio (ACR) test result is a the ratio of measured albumin (a protein) and creatinine (a metabolism by-product) in the urine that has been excreted from the body, at the time of the test (spot sample). Creatinine is produced by the body at a constant rate, depending on muscle mass, and is removed by the kidneys. If the kidneys do not have adequate filtering capabilities (impaired kidney function), creatinine levels rise in the body and albumin can leak into the urine, and this is referred to as albuminuria.1 The severity of ACR levels, or albuminuria, is indicated as microalbuminuria and macroalbuminuria. which refers to impaired kidney function, and normoalbuminuria referring to normal ACR levels (adequate kidney function).2

Population

Albumin and creatinine results were obtained for persons aged 5 years and over, who participated in the National Health Measures Survey (NHMS) and provided a urine sample. Note that only results for persons aged 18 years and over were published in the NHMS, as there is no validated ACR level for determining impaired kidney function for children (0-17 years). Fasting was not required for this test.

Methodology

A urine sample was collected from participants and urinary albumin and creatinine levels were measured at the Douglass Hanly Moir (DHM) laboratory.

In the NHMS, cut off reference values for albuminuria were sourced from the chronic disease position statement put out by the Medical Journal of Australia; and the Chronic Kidney Disease (CKD) management guidelines by Kidney Health Australia.2,3 These guidelines are based on epidemiological data and publications of major clinical trials.

In the NHMS, the following definitions were used for albuminuria (ACR levels):

Cut off points for Albuminuria (ACR) in the NHMS

ACR levels for males
(mg/mmol)
ACR levels for females
(mg/mmol)

Normoalbuminuria (Normal)<2.5<3.5
Microalbuminuria2.5 to 25.03.5 to 35.0
Macroalbuminuria>25.0>35.0


Further test information about the analysis method and machine used to measure ACR levels is available in Excel spreadsheet format in the Downloads page of this product.

Data items

The data items and related output categories for this topic are available in Excel spreadsheet format from the Downloads page of this product.

Interpretation

Points to be considered when interpreting data for this topic include the following:
  • ACR test results do not confirm a specific diagnosis without consultation with a health professional.
  • There are a number of different test methods for measuring urine albumin and creatinine, which may produce different results. The data from this topic should therefore be used with caution when comparing ACR results from other studies using a different test method or equation.
  • Factors such as urinary tract infections, high protein diet intake or heavy exercise within 24 hrs are known to affect ACR results (other than chronic kidney disease).3 As a result, the data should be interpreted with care.

Comparability with other surveys

The NHMS is the first ABS survey to collect biomedical data on Chronic Kidney Disease.

Chronic Kidney Disease biomedical data has been collected in other non-ABS surveys. However, caution must be taken when interpreting results due to the differences in scope, assay and the instrument used, and any thresholds applied in the final analysis. Further information about these comparisons is available from the Comparisons with other Australian surveys section of the Biomedical Results for Chronic Diseases, 2011-12 publication.

ENDNOTES

1 Kidney Health Australia 2013, What is Kidney disease?, <http://www.kidney.org.au/kidneydisease/tabid/578/default.aspx>, Last accessed 13/11/2013.
2 Kidney Health Australia 2013, Chronic Kidney Disease (CKD) Management in General Practice. 2nd Edition 2012 <http://www.kidney.org.au/HealthProfessionals/CKDManagementinGeneralPractice/tabid/789/Default.aspx>, Last accessed 24/06/2013.
3 David W Johnson, Graham R D Jones, Timothy H Mathew, Marie J Ludlow, Stephen J Chadban, Tim Usherwood, Kevan Polkinghorne, Stephen Colagiuri, George Jerums, Richard MacIsaac and Helen Martin, Australasian Proteinuria Consensus Working Group 2012, Chronic kidney disease and measurement of albuminuria or proteinuria: a position statement, <https://www.mja.com.au/journal/2012/197/4/chronic-kidney-disease-and-measurement-albuminuria-or-proteinuria-position>, Last accessed 27/07/2013.

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