Test Catalog

Test Id : A124

Alpha-1-Microglobulin, 24 Hour, Urine

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

Assessment of renal tubular injury or dysfunction using 24-hour urine collections


Screening for tubular abnormalities


Detecting chronic asymptomatic renal tubular dysfunction(2)

Profile Information
A profile is a group of laboratory tests that are ordered and performed together under a single Mayo Test ID. Profile information lists the test performed, inclusive of the test fee, when a profile is ordered and includes reporting names and individual availability.

Test Id Reporting Name Available Separately Always Performed
AIM Alpha-1-Microglobulin, 24 HR, U No Yes
A1MCR A1M/Creat Ratio No Yes
A1MC Alpha-1-Microglobulin Concentration No Yes
CRT24 Creatinine, 24 HR, U Yes, (Order CTU) Yes

Special Instructions
Library of PDFs including pertinent information and forms related to the test

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

AIM, A1MCR: Calculation

A1MC: Immunonephelometry

CRT24: Enzymatic Colorimetric Assay

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


Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Alpha-1-Microglobulin, 24 HR, U

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


HC (Human Complex) Protein

Protein Human Complex (HC)

Specimen Type
Describes the specimen type validated for testing


Necessary Information

24-Hour volume is required.


Question ID Description Answers
TM10 Collection Duration
VL8 Urine Volume

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Container/Tube: Plastic, 5-mL tube

Specimen Volume: 4 mL

Collection Instructions:

1. Collect urine for 24 hours.

2. No preservative.

3. Mix well before taking 4-mL aliquot.

Additional Information: For multiple collections see Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens

Special Instructions
Library of PDFs including pertinent information and forms related to the test


If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.

Urine Preservative Collection Options

Note: The addition of preservative or application of temperature controls must occur within 4 hours of completion of the collection.







50% Acetic Acid


Boric Acid


Diazolidinyl Urea


6M Hydrochloric Acid


6M Nitric Acid


Sodium Carbonate







Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

1 mL

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

Gross hemolysis Reject

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Urine Refrigerated (preferred) 7 days
Ambient 7 days
Frozen 7 days

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

Assessment of renal tubular injury or dysfunction using 24-hour urine collections


Screening for tubular abnormalities


Detecting chronic asymptomatic renal tubular dysfunction(2)

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

Alpha-1-microglobulin is a low-molecular-weight protein of 26 kDa and a member of the lipocalin protein superfamily.(1) It is synthesized in the liver, freely filtered by glomeruli, and reabsorbed by renal proximal tubules cells where it is catabolized.(1) Due to extensive tubular reabsorption, under normal conditions very little filtered alpha-1-microglobulin appears in the final excreted urine. Therefore, an increase in the urinary concentration of alpha-1-microglobulin indicates proximal tubule injury and/or impaired proximal tubular function.


Elevated excretion rates can indicate tubular damage associated with renal tubulointerstitial nephritis or tubular toxicity from heavy metal or nephrotoxic drug exposure. Glomerulonephropathies and renal vasculopathies also are often associated with coexisting tubular injury and so may result in elevated excretion. Elevated alpha-1-microglobulin in patients with urinary tract infections may indicate renal involvement (pyelonephritis).


Measurement of urinary excretion of retinol-binding protein, another low-molecular-weight protein, is an alternative to the measurement of alpha-1-microglobulin. To date, there are no convincing studies to indicate that one test has better clinical utility than the other.


Urinary excretion of alpha-1-microglobulin can be determined from either a 24-hour collection or from a random urine collection. The 24-hour collection is traditionally considered the gold standard. For random or spot collections, the concentration of alpha-1-microglobulin is divided by the urinary creatinine concentration. This corrected value adjusts alpha-1-microglobulin for variabilities in urine concentration.

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.

> or =18 years: <23 mg/24 hours


Reference values have not been established for patients who are less than 18 years of age.

Provides information to assist in interpretation of the test results

Alpha-1-microglobulin above the reference values may be indicative of a proximal tubular dysfunction.

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

Since this is a nephelometric assay, turbidity and particles (eg, cells, crystals) in the specimen can interfere with the test.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Akerstrom B, Logdberg L, Berggard T, Osmark P, Lindqvist A: Alpha(1)-microglobulin: a yellow-brown lipocalin. Biochim Biophys Acta. 2000 Oct 18;1482(1-2):172-184

2. Yu H, Yanagisawa Y, Forbes M, Cooper EH, Crockson RA, MacLennan RC: Alpha-1-microglobulin: an indicator protein for renal tubular function. J Clin Pathol. 1983 Mar;36(3):253-259

3. Hjorth L, Helin I, Grubb A: Age-related reference limits for urine levels of albumin, orosomucoid, immunoglobulin G, and protein HC in children. Scand J Clin Lab Invest. 2000 Feb;60(1):65-73

4. Pagana K, Pagana T, Papana T, eds: Mosby’s Diagnostic and Laboratory Test Reference. Mosby; 2020:632

Special Instructions
Library of PDFs including pertinent information and forms related to the test

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


In an immunochemical reaction, alpha-1-microglobulin present in the urine sample forms immune complexes with anti-alpha-1-microglobulin specific antibodies. These complexes scatter a beam of light passed through the sample. The intensity of the scattered light is proportional to the concentration of alpha-1-microglobulin in the sample. The result is evaluated by comparison with a standard of known concentration.(Package insert: N Alpha-1-Microglobulin. Siemens Healthcare Diagnostics Inc; V5, 05/2018)



The enzymatic method 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: Creatinine plus ver 2. Roche Diagnostics; V 15.0, 03/2019)

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


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


Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

1 to 7 days

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
Indicates the location of the laboratory that performs the test


Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their account representative. For assistance, contact Customer Service.

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 instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

This test has been cleared, approved, or is exempt by the US 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 Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.


LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

Test Id Test Order Name Order LOINC Value
A124 Alpha-1-Microglobulin, 24 HR, U 99075-4
Result Id Test Result Name Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
TM10 Collection Duration 13362-9
VL8 Urine Volume 3167-4
CR_A Creatinine, 24 HR, U 2162-6
CR_24 Creatinine Concentration, 24 HR, U 20624-3
AIM Alpha-1-Microglobulin, 24 HR, U 48414-7
A1MC Alpha-1-Microglobulin Concentration 99076-2
A1MCR A1M/Creat Ratio 99075-4

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports

Test Update Resources

Change Type Effective Date
New Test 2021-06-24