Protocol - Urinary Microalbumin - Assay
This protocol provides basic instructions for collecting and processing urine according to National Health and Nutrition Examination Survey (NHANES) methods. Albumin concentration is measured according to a fluorescent immunoassay (FIA). The protocol also lists reference ranges for healthy adults.
The Diabetes Working Group (WG) recommends that the urine albumin assay be performed on urine collected during a participant’s first morning void but notes that a random sample is also acceptable.
Note from the Diabetes WG: Urine should be stored at -80°C until testing and shipped on dry ice to prevent thawing.
The Sickle Cell Disease Research and Scientific Panel notes that the terms "microalbuminuria" and "macroalbuminuria" have been used clinically to describe different levels of abnormal albumin excretion rate: 30-299 mg/g urine creatinine, and >300 mg/gr urine creatinine, for microalbuminuria and macroalbuminuria, respectively. Recently, a new terminology has been proposed: "low level albuminuria" instead of microalbuminuia, and "high level albuminuria" for macroalbuminuria, since the older terminology could be interpreted as measuring different molecular forms of albumin. Because albuminuria may be affected by non-pathological factors (exercise, menstruation contamination, biological variability, etc.), abnormal values should be confirmed within 1-2 months.
The following is a summary version of the full National Health and Nutrition Examination Survey 2007-2008 protocol.
Editor’s Note: Please review chapter 5 of the Laboratory Procedures Manual from the National Health and Nutrition Examination Survey 2007-2008 for a full description of urine collection and processing procedures: 2007-2008 NHANES Lab Manual.
The coordinator explains the following instructions to the subject before urine collection:
• Wash hands with soap and water;
• It is important that the cup and cap not touch or come into contact with any parts of the body, clothing, or external surfaces; and
• Close container to minimize exposure to air.
Refrigerate all insufficient urine samples. When additional urine is obtained, pool the urine, mix, and process.
Record the Results of Urine Specimen Collection
Note whether or not urine was collected, and note whether the volume of urine was sufficient or required a second specimen.
Note whether blood is present/visible in the specimen.
Process the Urine for the Urinary Albumin Assay
Pour 3 mL of the specimen for urine albumin into a 5 mL vessel.
Laboratory Procedure for Urinary Albumin
The Diabetes Working Group (WG) recommends that urine albumin concentration be determined according to a fluorescent immunoassay such as the one developed by the University of Minnesota for use in the National Health and Nutrition Examination Survey: Urinary Albumin Lab Assay.
To aid comparability, the Diabetes WG recommends that the investigator record the make and manufacturer of equipment used and the repeatability and coefficients of variation for the assay.
(From the NHANES/University of Minnesota laboratory protocol)
Urinary Albumin in Healthy Subjects
Number of Subjects
Chavers et al. (1994)
Howey et al. (1987)
Fielding et al. (1983)
Jones et al. (2002)
* obtained from subject data in the published manuscript. ** calculated from published units. + mean values.
Protocol Name from Source:
2007 National Health and Nutrition Examination Survey (NHANES) Laboratory Procedures Manual, University of Minnesota Laboratory Procedures Manual for Urinary Albumin
Personnel and Training Required
Personnel to collect the urine Laboratory to perform the fluorescent immunoassay
Supplies to collect and process urine
|Specialized requirements for biospecimen collection||No|
|Average time of greater than 15 minutes in an unaffected individual||No|
Mode of Administration
Child, Adolescent, Adult, Senior
Participants 6 years of age and older
The National Health and Nutrition Examination Survey 2007-2008 protocol was selected as the best methodology and one of the most widely used protocols to measure urine creatinine. Additionally, the fluorescent immunoassay (FIA) protocol used by NHANES and developed by the University of Minnesota has been used in other studies, including Atherosclerosis Risk in Communities (ARIC) and Family Investigation of Nephropathy and Diabetes (FIND).
|Common Data Elements (CDE)||Urine Albumin To Creatinine Protein Ratio Measurement Value in mg/l||3070901||CDE Browser|
|Logical Observation Identifiers Names and Codes (LOINC)||Urinary microalbumin assay proto||62809-9||LOINC|
Microalbuminaria Ratio of urine microalbumin to urine creatinine
Ratio of albumin / creatinine (ug/mg)
Process and Review
The Expert Review Panel #1 reviewed the measures in the Anthropometrics, Diabetes, Physical Activity and Physical Fitness, and Nutrition and Dietary Supplements domains.
Guidance from the ERP includes:
Changed the name of measure
Revised descriptions of measure
Back-compatible: no changes to Data Dictionary
Previous version in Toolkit archive (link)
Centers for Disease Control and Prevention (CDC), National Center for Health Statistics (NCHS). (2007). National Health and Nutrition Examination Survey Questionnaire. Laboratory Procedures Manual. Hyattsville, MD: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention.
Centers for Disease Control and Prevention (CDC), National Center for Health Statistics (NCHS). (2007). National Health and Nutrition Examination Survey Questionnaire. University of Minnesota Laboratory Procedures Manual for Urinary Albumin by Sequoia-Turner Digital Fluorometer, Model 450. Hyattsville, MD: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention.
References for Reference Values from the lab protocol:
Allon, M., Lawson, L., Eckman, J.R., Delaney, V., & Bourke, E. (1988). Effects of nonsteroidal antiinflammatory drugs on renal function in sickle cell anemia. Kidney International, 34, 500-506.
American Diabetes Association (ADA). (2014a). Diagnosis and classification of diabetes mellitus. Diabetes Care, 37(Suppl. 1), S81-S90.
American Diabetes Association (ADA). (2014b). Standards of Medical Care in Diabetes-2014. Diabetes Care, 37(Suppl. 1), S14-S80.
Chavers, B. M., Mauer, S. M., Ramsay, R. C., & Steffes, M. W. (1994). Relationship between retinal and glomerular lesions in IDDM patients. Diabetes, 43, 441-446.
de Jong, P.E., de Jong-Van Den Berg, T.W., Sewrajsingh, G.S., Schouten, H., Donker, A.J.M., & Statius van Eps, L.W. (1980). The influence of indomethacin on renal hemodynamics in sickle cell anemia. Clinical Science, 59, 245-250.
Guasch, A., Cua, M., & Mitch, W.E. (1996). Early detection and the course of glomerular injury in patients with sickle cell anemia. Kidney International, 49, 786-791.
Guasch, A., Navarrete, J., Zayas, C.F., Nass, K., & Eckman, J.R. (2006). Glomerular involvement in adults with sickle hemoglobinopathies: prevalence and clinical correlates of progressive renal failure. Journal of the American Society of Nephrology, 17, 2228-2235.
Fielding, B. A., Price, D. A., & Houlton, C. A. (1983). Enzyme immunoassay for urinary albumin. Clinical Chemistry, 29, 355-357.
Howey, J. E. A., Browning, M. C. K., & Fraser, C. G. (1987). Selecting the optimum specimen for assessing slight albuminuria, and a strategy for clinical investigation: novel uses of data on biological variation. Clinical Chemistry, 33, 2032-2038.
Jones, C. A, Francis, M. E., Eberhardt, M. S., Chavers, B. Coresh, J., Engelgau, M., . . . Agodoa, L. Y. (2002). Microalbuminuria in the US population: Third National Health and Nutrition Examination Survey. American Journal of Kidney Diseases, 39, 445-459.
Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. (2013). KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney International Supplement, 3, 1-150.
Mogenson, C. E. (1976). Renal function changes in diabetes. Diabetes, 25, 872-879.
|Variable Name||Variable ID||Variable Description||Version||dbGaP Mapping|
|PX141501_Assay_Repeatability||PX141501040000||Repeatability of the assay||4||N/A|
|PX141501_Coefficient_Of_Variation||PX141501050000||Coefficient of variation for the assay||4||N/A|
|PX141501_Equipment_Make||PX141501030100||Make of the equipment used to determine the concentration of urinary microalbumin.||4||N/A|
|PX141501_Equipment_Manufacturer||PX141501030200||Manufacturer of the equipment used to determine the concentration of urinary microalbumin.||4||N/A|
|PX141501_Sample_Comments||PX141501020000||Record any comments about the urine during processing.||4||N/A|
|PX141501_Urinary_Microalbumin_Concentration||PX141501060000||Concentration of urinary microalbumin||4||N/A|
|PX141501_Urine_Collection_Comments||PX141501010000||Record any comments about the urine collection, including whether or not urine was collected, whether the volume of urine was sufficient or required a second specimen, and whether blood is present or visible in the specimen.||4||N/A|
Urinary Microalbumin - Assay
October 1, 2015
A bioassay to measure urine concentration of albumin, which is produced by the liver and is the most abundant protein in the blood
Albumin is only filtered out of blood by the kidneys when there is damage to the glomeruli, as in diabetes. The earliest measure of this damage is the appearance of small (micro-) amounts of albumin in the urine. Additionally, the ratio of urine albumin to urine creatinine, called microalbuminuria, is used to predict the risk of nephropathy (National Health and Nutrition Examination Survey and University of Minnesota Laboratory Procedure Manual for Urinary Creatinine, 2008).
Diabetes, nephropathy, kidney, kidney disease, kidney failure, microalbuminuria, macroalbuminuria, NHANES