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Protocol - Urinary Microalbumin - Assay

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Protocol Name from Source:

2007 National Health and Nutrition Examination Survey (NHANES) Laboratory Procedures Manual, University of Minnesota Laboratory Procedures Manual for Urinary Albumin

Availability:

Publicly available

Description:

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.

Protocol:

The following is a summary version of the full National Health and Nutrition Examination Survey 2007-2008 protocol.

Urine Collection

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: [link[www.phenxtoolkit.org/toolkit_content/supplemental_info/diabetes/additional_info/NHANES_Lab_Manual.pdf|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: [link[www.phenxtoolkit.org/toolkit_content/supplemental_info/diabetes/additional_info/NHANES_Urinary_Albumin.pdf|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.

REFERENCE RANGES

(From the NHANES/University of Minnesota laboratory protocol)

Urinary Albumin in Healthy Subjects

Number of Subjects

Author

Method

mg/L μg/mL

μg/min

mg/24 h

100 adults

Chavers et al. (1994)

FIA

0.2-17.3*

0.8-14.6

1.1-21.0

20 adults

Mogenson (1976)

RIA

5-20

3.6-23.0

11 adults

Howey et al. (1987)

RIA

8.13+

7.1**,+

10.2+

20 children

Fielding et al. (1983)

ELISA

1.2-15.9**

1.7-22.9

NHANES III

Jones et al. (2002)

FIA

< 30

* obtained from subject data in the published manuscript. ** calculated from published units. + mean values.

Personnel and Training Required

Personnel to collect the urine Laboratory to perform the fluorescent immunoassay

Equipment Needs

Supplies to collect and process urine

Requirements

Requirement CategoryRequired
Average time of greater than 15 minutes in an unaffected individualNo
Major equipmentNo
Specialized requirements for biospecimen collectionNo
Specialized trainingNo

Mode of Administration

Self-administered

Life Stage:

Child, Adolescent, Adult, Senior

Specific Instructions:

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.

Research Domain Information

Release Date:

October 1, 2015

Definition

A bioassay to measure urine concentration of albumin, which is produced by the liver and is the most abundant protein in the blood

Purpose

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).

Selection Rationale

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).

Language

English, Spanish

Standards

StandardNameIDSource
Common Data Elements (CDE)Urine Albumin To Creatinine Protein Ratio Measurement Value in mg/l3070901CDE Browser
Logical Observation Identifiers Names and Codes (LOINC)Urinary microalbumin assay proto62809-9LOINC

Process and Review

The [link[phenx.org/node/62|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[www.phenxtoolkit.org/index.php?pageLink=browse.archive.protocols&id=140000|link]])

Source

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.

General References

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.

Protocol ID:

141501

Variables:

Export Variables
Variable NameVariable IDVariable DescriptionVersiondbGaP Mapping
PX141501_Urine_Collection_CommentsPX141501010000Record 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.4N/A
PX141501_Sample_CommentsPX141501020000Record any comments about the urine during processing.4N/A
PX141501_Equipment_MakePX141501030100Make of the equipment used to determine the concentration of urinary microalbumin.4N/A
PX141501_Equipment_ManufacturerPX141501030200Manufacturer of the equipment used to determine the concentration of urinary microalbumin.4N/A
PX141501_Assay_RepeatabilityPX141501040000Repeatability of the assay4N/A
PX141501_Coefficient_Of_VariationPX141501050000Coefficient of variation for the assay4N/A
PX141501_Urinary_Microalbumin_ConcentrationPX141501060000Concentration of urinary microalbumin4N/A