Test ID: ACANT
Acanthamoeba/Naegleria species, Corneal Scraping or Spinal Fluid
NY State Approved 
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Diagnosis of Acanthamoeba species and Naegleria fowleri, in central nervous system or ocular specimens
Method Name A short description of the method used to perform the test
Direct Wet Prep/Culture
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Culture for Acanthamoeba, Spinal Fluid
Culture for Naegleria, Corneal Scrapings
Culture for Naegleria, Spinal Fluid
Detection of Acanthamoeba/Naegleria Species, Corneal Scrapings or CSF
Specimen Type Describes the specimen type needed for testing
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.
Forms: If not ordering electronically, submit a Microbiology Request Form (Supply T244) with the specimen.
Specimen source is required.
Submit only 1 of the following specimens:
Specimen Type: Central nervous system tissue
Container/Tube: Sterile container with 1 mL of saline or minimal essential medium
Specimen Volume: Entire collection
Specimen Stability Information: Ambient
Specimen Type: Contact lens, corneal scraping, corneal tissue
Container/Tube: Sterile container with 1 mL of saline or minimal essential medium
Specimen Volume: Entire collection
Additional Information: The preferred specimen for Acanthamoeba culture from an ocular source is corneal scraping or biopsy. Swab is suboptimal and may result in a falsely negative result. Supplementary slides may be submitted in addition to the scraping or biopsy, but slides alone will not be accepted for testing.
Specimen Stability Information: Ambient (preferred)/Refrigerated
Specimen Type: Contact lens solution
Container/Tube: Sterile container
Specimen Volume: 2 mL
Specimen Stability Information: Ambient (preferred)/Refrigerated
Specimen Type: Spinal fluid
Container/Tube: Sterile vial
Specimen Volume: 1 mL
Specimen Stability Information: Ambient
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.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | NA |
| Lipemia | NA |
| Icterus | NA |
| Other | Slides only received and samples received on wood swabs |
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 Type | Temperature | Time |
|---|---|---|
| Varies | Varies | 7 days |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
The free-living amebae are ubiquitous in the environment, and may be found in soil and fresh water sources. Naegleria fowleri may enter the central nervous system (CNS) during exposure to infected water and cause a fulminant meningitis in previously healthy individuals. In contrast, Acanthamoeba species and Balamuthis mandrillaris cause chronic granulomatous encephalitis in immunocompromised (and, rarely, immunocompetent) adults, and typically disseminate to the CNS from a primary lung or skin source.
Acanthamoeba species can also cause a painful keratitis when organisms are introduced into the eye. This typically occurs during contact lens use when the lenses or storage or cleaning solutions are contaminated. Amebae can also enter the cornea with abrasion or trauma. Amebic keratitis can cause blindness if untreated. Most cases respond to treatment once a diagnosis is made, but some cases prove to be resistant to therapy with no antimicrobials uniformly active against the organisms.
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.
EYE
Negative for Acanthamoeba species
CENTRAL NERVOUS SYSTEM
Negative for Acanthamoeba/Naegleria species
Interpretation Provides information to assist in interpretation of the test results
Organisms seen on stains of the original specimen smear or growth on culture media are positive tests.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
The preferred specimens for Acanthamoeba ocular culture are corneal scrapings or biopsy. Swabs are suboptimal and may result in a falsely negative result. Submission of slides without material for culture is not acceptable.
Wooden-handled swabs are unacceptable for culture since the wood may contain preservatives or other chemicals inhibitory to Acanthamoeba or Naegleria growth.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Acanthamoeba keratitis multiple states, 2005-2007. MMWR Morb Mortal Wkly Rep 2007;56(21):532-534
2. Kumar R, Lloyd D: Recent advances in the treatment of Acanthamoeba keratitis. Clin Infect Dis 2002 Aug 15;35(4):434-441
3. Yoder JS, Eddy BA, Visvesvara GS, et al: The epidemiology of primary amoebic meningoencephalitis in the USA, 1962-2008. Epidemiol Infect 2009 Oct;22:1-8
4. Schuster FL: Cultivation of pathogenic and opportunistic free-living amebas. Clin Microbiol Rev 2002 Jul;15(3):342-354
Method Description Describes how the test is performed and provides a method-specific reference
Direct wet preps of the spinal fluid and trichrome-stained smears of the corneal scrapings (if slides are submitted) are examined microscopically. In addition, the specimens are cultured on nonnutrient agar plates prepared using tap water. These plates are also inoculated with the bacterium, Escherichia coli. Coincubation with bacteria enhances the growth of these amebae, which usually occurs after 2 to 4 days of incubation at ambient temperature. The agar surface is examined microscopically for the presence of amebae. (Ma P, Visvesvara GS, Martinez AJ, et al: Naegleria and Acanthamoeba infections. Rev Infect Dis 1990;12:490-513)
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.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
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.
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.
87081
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 ID | Reporting Name | LOINC Code |
|---|---|---|
| ACANT | Acanthamoeba/Naegleria, Corneal/CSF | In Process |
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