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Test ID: RMA
Microalbumin, Random, Urine

Secondary ID A test code used for billing and in test definitions created prior to November 2011

81260

NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Useful For Suggests clinical disorders or settings where the test may be helpful

Assessing the potential for early onset of nephropathy in diabetic patients

Method Name A short description of the method used to perform the test

Immunoturbidity/Enzymatic Colorimetric Assay

Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name

Microalbumin-Random, U

Aliases Lists additional common names for a test, as an aid in searching

Albumin
Albumin/Creatinine Ratio
Microalbumin
Microalbumin, Random Collection
Random Microalbuminuria
Albumin, Urine Test performed at Mayo New England
Albumin/Creatinine Ratio Test performed at Mayo New England
Random Microalbuminuria, Urine

Specimen Type Describes the specimen type needed for testing

Urine

Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.

Container/Tube: Plastic, 10-mL urine tube (Supply T068)

Specimen Volume: 5 mL

Collection Instructions:

1. Collect a random urine specimen.

2. No preservative.

Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.

1 mL

Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected

Hemolysis

NA

Lipemia

NA

Icterus

NA

Other

NA

Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.

Specimen TypeTemperatureTime
UrineRefrigerated (preferred)7 days
 Ambient 7 days
 Frozen 7 days

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Diabetic nephropathy is a complication of diabetes and is characterized by proteinuria (normal urinary albumin excretion is <30 mg/day; overt proteinuria is >300 mg/day). Before overt proteinuria develops, albumin excretion increases in those diabetic patients who are destined to develop diabetic nephropathy. Therapeutic maneuvers (eg, aggressive blood pressure maintenance, particularly with angiotensin-converting enzyme inhibitors; aggressive blood sugar control; and possibly decreased protein intake) can significantly delay, or possibly prevent, development of nephropathy. Thus, there is a need to identify small, but abnormal, increases in the excretion of urinary albumin (in the range of 30-300 mg/day, ie, microalbuminuria).

 

The National Kidney Foundation guidelines for the management of patients with diabetes and microalbuminuria recommend that all type 1 diabetic patients older than 12 years and all type 2 diabetic patients younger than 70 years have their urine tested for microalbuminuria yearly when they are under stable glucose control.(1)

 

The preferred specimen is a 24-hour collection, but a random collection is acceptable. Studies have shown that correcting albumin for creatinine excretion rates has similar discriminatory value with respect to diabetic renal involvement. The albumin/creatinine ratio from a random urine specimen is also considered a valid screening tool.(3) Several studies have addressed whether the specimen needs to be a fasting urine, an exercised urine, or an overnight urine specimen. These studies have shown that the first-morning urine specimen is less sensitive, but more specific.

 

Studies also have shown that microalbuminuria is a marker of generalized vascular disease and is associated with stroke and heart disease.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Males: <17 mg/g creatinine

Females: <25 mg/g creatinine

Interpretation Provides information to assist in interpretation of the test results

In random urine specimens, normal urinary albumin excretion is <17 mg/g creatinine for males and <25 mg/g creatinine for females.(2)

 

Microalbuminuria is defined as an albumin/creatinine ratio of 17 to 299 for males and 25 to 299 for females.

 

A ratio of albumin/creatinine of > or =300 is indicative of overt proteinuria.

 

Due to biologic variability, positive results should be confirmed by a second, first-morning random or 24-hour timed urine specimen. If there is discrepancy, a third specimen is recommended. When 2 out of 3 results are in the microalbuminuria range, this is evidence for incipient nephropathy and warrants increased efforts at glucose control, blood pressure control, and institution of therapy with an ACE inhibitor (if the patient can tolerate it).

 

On 02/10/2009, the reagent system used for the immunoturbidimetric albumin assay was changed. This resulted in a small but statistically significant change in albumin measurements. To directly compare results after the date of this method change to previous values, the old urinary albumin concentration should be multiplied by 1.11. Given the normal physiologic variability of albumin excretion in individuals and the small magnitude of this correction factor, in most instances this calculation will not be necessary for clinical management of patients.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Urine collected during menses may contain excess albumin and collection during this time should be avoided.

 

Heavy exercise may increase albumin excretion and should be avoided during collection. Normal values apply to a nonexercised state.

 

Bilirubin at 20 mg/dL reduces creatinine by 15% to 20%.

Clinical Reference Provides recommendations for further in-depth reading of a clinical nature

1. Bennett PH, Haffner S, Kasiske BL, et al: Diabetic Renal Disease Recommendations-Screening and management of microalbuminuria in patients with diabetes mellitus: Recommendations to the Scientific Advisory Board of the National Kidney Foundation from an ad hoc committee of the Council on Diabetes Mellitus of the National Kidney Foundation. Am J Kidney Dis 1995;25:107-112

2. Krolewski AS, Laffel LM, Krolewski M, et al: Glycosylated hemoglobin and the risk of microalbuminuria in patients with insulin-dependent diabetes mellitus. N Engl J Med 1995;332:1251-1255

3. Zelmanovitz T, Gross JL, Oliveira JR, et al: The receiver operating characteristics curve in the evaluation of a random urine specimen as a screening test for diabetic nephropathy. Diabetes Care 1997;20:516-519

4. Package insert: Tina-Quant Albumin reagents kit for urinary albumin, Roche Diagnostics, Indianapolis, IN

Method Description Describes how the test is performed and provides a method-specific reference

Albumin is measured by immunoturbidimetry utilizing antibody to human albumin in an automated immunoprecipitin analysis system.(Package insert: Tina-Quant Albumin Reagents Kit for urinary albumin, Roche Diagnostics, Indianapolis, IN, March 2007)

 

Creatinine is measured by the enzymatic method, which is based on the determination of sarcosine from creatinine with the aid of creatininase, creatinase, and sarcosine oxidase. The liberated hydrogen peroxide is measured via a modified Trinder reaction using a colorimetric indicator. Optimization of the buffer system and the colorimetric indicator enables the creatinine concentration to be quantified both precisely and specifically.(Package insert: Roche Diagnostics, Indianapolis IN, September 2009)

Supplemental Report Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.

Monday through Sunday; Continuously

Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.

1 day

Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result

1 day

Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

7 days

Performing Laboratory Location The location of the laboratory that performs the test

Rochester

Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.

This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

82043

LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.

Result IDReporting NameLOINC Code
RMALBMicroalbumin-Random, U14957-5
MALB1Microalbumin14957-5
CRE2Creatinine2161-8
A_CRAlbumin/Creatinine Ratio9318-7