Test Catalog

Test Id : IL5P

Interleukin 5, Plasma

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

Evaluation of patients with disorders known to be associated with hypereosinophilia

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

Electrochemiluminescence (ECL)

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

Interleukin 5, P

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




Specimen Type
Describes the specimen type validated for testing

Plasma EDTA

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

Collection Container/Tube: Lavender top (EDTA)

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions:

1. Immediately after specimen collection, place the tube on wet ice.

2. Centrifuge at 1500 x g for 10 minutes and aliquot plasma into plastic vial.

3. Freeze specimen within 30 minutes.

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

0.3 mL

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

Gross hemolysis Reject
Gross lipemia OK
Gross icterus OK
Heat-treated specimen 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
Plasma EDTA Frozen (preferred) 21 days
Refrigerated 24 hours

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

Evaluation of patients with disorders known to be associated with hypereosinophilia

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

Interleukin-5 (IL-5), a homodimer composed of two 20-kDa subunits, is expressed primarily by CD4+ Th2 (helper T cells, subset 2) cells and, to a lesser extent, by activated mast cells.(1,2) IL-5 acts on mature eosinophils, leading to proliferation, activation, differentiation, and survival.


IL-5 plays a critical role in the host immune response to helminthic infections and has been implicated in the pathology of certain allergic diseases, asthma, and vasculitis.(1-3) In these diseases, it is associated with significant increase in levels of eosinophils, a condition referred to as hypereosinophilia. IL-5 is known to activate eosinophils, which interact through their Fc receptors to bind helminths that have been opsonized by IgG or IgA specific antibodies.(1) Of the other diseases associated with IL-5 and hypereosinophilia, those of the skin and airways (urticaria, asthma, allergic bronchopulmonary aspergillosis, and eosinophilic granulomatosis with polyangiitis [EGPA]) have received considerable attention recently due to availability of therapies that target the IL-5 pathways.(4) In EPGA, increased levels of IL-5 have been seen in a subset of patients with implications for disease management.(4,5) The IL-5 pathway-directed therapies have been also been approved for use in patients with severe eosinophilic asthma. With availability of these therapies, it is likely that IL-5 cytokine testing may be used to identify patients at-risk for 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.

< or =1.0 pg/mL

Provides information to assist in interpretation of the test results

Elevated concentrations of interleukin-5 (IL-5) may indicate an expanded Th2 (helper T cells, subset 2)-immune response, which may be associated with hypereosinophilia.

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

Interleukin-5 (IL-5) is a nonspecific marker associated with a Th2 (helper T cells, subset 2)-immune response and is not diagnostic for any specific disease or disease process. Elevated concentrations of IL-5 must be interpreted within the clinical context of the patient.


Normal concentrations of IL-5 do not exclude the possibility of a Th2-immune response or hypereosinophilia.


IL-5 has limited stability. Following centrifugation, plasma must be either immediately frozen or refrigerated. Samples can only be stored at refrigerated temperatures for 24 hours, after which time samples must be frozen. Storage of plasma for any length of time at room temperature is not acceptable.

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

1. Nakayama T, Hirahara K, Onodera A, et al: Th2 cells in health and disease. Annu Rev Immunol. 2017 Apr 26;35:53-84

2. Yanagibashi T, Satoh M, Nagai Y, et al. Allergic diseases: From bench to clinic - Contribution of the discovery of interleukin-5. Cytokine. 2017 Oct;98:59-70.

3. Kandikattu HK, Venkateshaiah SU, Mishra A: Synergy of interleukin (IL)-5 and IL-18 in eosinophil mediated pathogenesis of allergic diseases. Cytokine Growth Factor Rev. 2019;47:83-98.

4. Harish A, Schwartz SA: Targeted anti-IL-5 therapies and future therapeutics for hypereosinophilic syndrome and rare eosinophilic conditions. Clin Rev Allergy Immunol. 2020;59:231-247.

5. Nishi R, Ohyama K, Fukami Y et al: Association between IL-5 levels and the clinicopathologic features of eosinophilic granulomatosis with polyangiitis. Neurology. 2021;96:226-229.

6. Melo JT Jr, Tunstall T, Pizzichini R, et al: IL-5 levels in nasosorption and sputosorption correlate with sputum eosinophilia in allergic asthma. Am J Respir Crit Care Med. 2019;199:240-243.

7. Guntur VP, Manka LA, Denson JL, et al: Benralizumab as a steroid-sparing treatment option in eosinophilic granulomatosis with polyangiitis. J Allergy Clin Immunol Pract. 2021;1186-1193.

8. Hillas G, Fouka E, Papaioannou A: Antibodies targeting the interleukin-5 signaling pathway used as add-on therapy for patients with severe eosinophilic asthma: a review of the mechanism of action, efficacy, and safety of the subcutaneously administered agents, mepolizumab and benralizumab. Expert Rev Respir Med. 2020;14(4):353-365.

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

The interleukin-5 (IL-5) cytokine assay measures human cytokines in a 96-well spotted plate. The assay employs a sandwich immunoassay format where capture antibodies are coated on a single spot on the bottom of each well. Diluted samples, calibrators, and controls are added and to the plate. If present, IL-5 will bind to the capture antibodies. After incubation, a solution containing detection antibodies conjugated with electrochemiluminescent labels is added. After a final incubation, a buffer is added that creates the appropriate chemical environment for electrochemiluminescence. The plate is then read on the MSD QuickPlex SQ120. The machine applies a voltage that causes bound labels to emit measurable light. The MSD QuickPlex SQ120 measures the intensity of emitted light and correlates it to a set of standards of known quantity via a 4-point logistics curve fitting method.(Unpublished Mayo method)

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 8 days

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

14 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.

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  • Prospective clients should contact their Regional Manager. 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 was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

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
IL5P Interleukin 5, P 33938-2
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.
36519 Interleukin 5, P 33938-2

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