Test Catalog

Test Id : AIHL

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Aminoglycoside-Induced Hearing Loss, Targeted Variant Testing, Droplet Digital PCR, Varies

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Overview

Test Catalog

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

Identification of individuals who may be at risk for aminoglycoside-induced hearing loss (AIHL)

 

Establishing a diagnosis of late-onset sensorineural hearing loss associated with aminoglycoside exposure

 

Identifying mitochondrial variants associated with AIHL, allowing for predictive testing of at-risk family members

Genetics Test Information
Provides information that may help with selection of the correct genetic test or proper submission of the test request

This test detects 2 mitochondrial gene RNR1 (MT-RNR1) variants, m.1555A>G and m.1494C>T, which are the most common variants associated with aminoglycoside induced ototoxicity.

Highlights

This test uses droplet digital polymerase chain reaction to evaluate for the presence of 2 mitochondrial variants associated with aminoglycoside-induced hearing loss.

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

Droplet Digital Polymerase Chain Reaction (ddPCR)

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

Yes

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

Aminoglycoside-Induced Hearing Loss

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

Aminoglycoside-induced hearing loss

Aminoglycoside ototoxicity

Deafness, aminoglycoside-induced

MT-RNR1 m.1494C>T

MT-RNR1 m.1555A>G

Specimen Type
Describes the specimen type validated for testing

Varies

Ordering Guidance

The preferred genetic test for diagnosis in individuals with suspicion of syndromic or non-syndromic hereditary hearing loss is HHLP / AudioloGene Hereditary Hearing Loss Panel, Varies.

Shipping Instructions

Specimen preferred to arrive within 96 hours of collection.

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

Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. Call 800-533-1710 for instructions for testing patients who have received a bone marrow transplant.

 

Specimen Type: Whole blood

Container/Tube:

Preferred: Lavender top (EDTA) or yellow top (ACD)

Acceptable: Any anticoagulant

Specimen Volume: 3 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send specimen in original tube.

Specimen Stability Information: Ambient/Refrigerated/Frozen

Additional Information: To ensure minimum volume and concentration of DNA is met, the preferred volume of blood must be submitted. Testing may be canceled if DNA requirements are inadequate.

 

Specimen Type: Saliva

Patient Preparation: Patient should not eat, drink, smoke, or chew gum 30 minutes prior to collection.

Supplies: Saliva Collection Kit (T786)

Specimen Volume: 1 swab

Collection Instructions: Collect and send specimen per kit instructions.

Specimen Stability Information: Ambient

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

Forms

1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing (Spanish) (T826)

2. Molecular Genetics Hereditary Hearing Loss Patient Information

3. If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.

See Specimen Required

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

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

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
Varies Varies

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

Identification of individuals who may be at risk for aminoglycoside-induced hearing loss (AIHL)

 

Establishing a diagnosis of late-onset sensorineural hearing loss associated with aminoglycoside exposure

 

Identifying mitochondrial variants associated with AIHL, allowing for predictive testing of at-risk family members

Genetics Test Information
Provides information that may help with selection of the correct genetic test or proper submission of the test request

This test detects 2 mitochondrial gene RNR1 (MT-RNR1) variants, m.1555A>G and m.1494C>T, which are the most common variants associated with aminoglycoside induced ototoxicity.

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

Aminoglycosides (tobramycin, streptomycin, and gentamicin, etc) are a group of broad-spectrum antibiotics commonly prescribed for infections caused by Gram-negative bacteria. In the United States alone, approximately 4 million courses of aminoglycosides are administered each year with approximately 2% to 5% of patients treated developing clinically significant hearing loss. Mitochondrial gene RNR1 (MT-RNR1) variants m.1555A>G and m.1494C>T are the most common variants associated with aminoglycoside-induced ototoxicity. Hearing loss associated with aminoglycoside exposure can occur even after a single dose and may be bilateral, irreversible, and often severe to profound. Avoidance of aminoglycoside antibiotics reduces the risk of developing hearing loss for individuals carrying one of these 2 variants.

 

The severity and onset of hearing loss in individuals with the associated pathogenic mitochondrial variants range from profound congenital deafness to mild to moderate late-onset hearing loss. Evidence demonstrates that this variance can often be explained by variant load in an individual. In contrast to variants in nuclear genes, which are present in either 0, 1, or 2 copies, mitochondrial variants can be present in any fraction of the total organelles, a phenomenon known as heteroplasmy. Penetrance of hearing loss without exposure to aminoglycosides is thought to be a function of the degree of heteroplasmy, with a correlation between higher fraction of altered mitochondria and higher penetrance. Hearing loss is believed to be 100% penetrant in homoplasmic individuals who receive aminoglycoside antibiotics.

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.

An interpretive report will be provided.

Interpretation
Provides information to assist in interpretation of the test results

An interpretive report will be provided.

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

Clinical Correlations:

Test results should be interpreted in context of clinical findings, family history, and other laboratory data. Misinterpretation of results may occur if the information provided is inaccurate or incomplete.

 

If testing was performed because of a clinically significant family history, it is often useful to first test an affected family member. Detection of a reportable variant in an affected family member would allow for more informative testing of at-risk individuals.

 

Technical Limitations:

This assay will not detect all variants or genes that cause mitochondrial nonsyndromic hearing loss and deafness. Therefore, the absence of a detectable variant does not rule out the possibility that an individual is a carrier of or affected with mitochondrial non-syndromic hearing loss and deafness.

 

Some individuals who are a carrier or have a diagnosis of mitochondrial nonsyndromic hearing loss and deafness may have a variant that is not identified by this assay. The absence of a variant, therefore, does not eliminate the possibility of a hereditary hearing loss disorder. For predictive testing of asymptomatic individuals, it is important to first document the presence of a gene variant in an affected family member.

 

Of note, absence of the mitochondrial variants MT-RNR1 m.1494C>T or MT-RNR1 m.1555A>G does not rule out the presence of these variants below the limits of detection of this assay (<5% heteroplasmy).

 

Rare alterations exist that could lead to false-negative or false-positive results. If results obtained do not match clinical findings, additional testing should be considered.

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

1. Gao Z, Chen Y, Guan MX: Mitochondrial DNA mutations associated with aminoglycoside induced ototoxicity. J Otol. 2017 Mar;12(1):1-8

2. Krause KM, Serio AW, Kane TR, Connolly LE: Aminoglycosides: An overview. Cold Spring Harb Perspect Med. 2016 Jun 1;6(6):a027029

3. Qian Y, Guan MX: Interaction of aminoglycosides with human mitochondrial 12S rRNA carrying the deafness-associated mutation. Antimicrob Agents Chemother. 2009 Nov;53(11):4612-4618

4. Usami S, Nishio S: Nonsyndromic hearing loss and deafness, mitochondrial. In: Adam MP, Ardinger HH, Pagon RA, et al, eds. GeneReviews [Internet]. University of Washington, Seattle; 2004. Updated June 14, 2018. Accessed March 15, 2021. Available at www.ncbi.nlm.nih.gov/books/NBK1422/

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

This test is a droplet digital polymerase chain reaction method for the detection of MT-RNR1 m.1494C>T and MT-RNR1 m.1555A>G associated with aminoglycoside-induced hearing loss. Variant nomenclature is based on the following GenBank Accession number (build GRCh37 [hg19]): NC_012920.1.(Unpublished Mayo method)

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

No

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.

Monday through Saturday

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-Specimens must arrive in the performing laboratory by 12 p.m. for the report to be available 1 day from specimen receipt.

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

Whole Blood: 2 weeks (if available); Extracted DNA: Indefinitely

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

Rochester

Fees
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 was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It 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.

81401

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
AIHL Aminoglycoside-Induced Hearing Loss In Process
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.
609786 Specimen 31208-2
609787 Source 31208-2
609788 Result Summary 50397-9
609789 Result 82939-0
609790 Interpretation 69047-9
609791 Additional Information 48767-8
609792 Method 85069-3
609793 Disclaimer 62364-5
609794 Released By 18771-6

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