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Test Code ACARP Acanthamoeba species Molecular Detection, PCR, Ocular

Useful For

Aids in the diagnosis of amebic keratitis in conjunction with clinical findings

Method Name

Real-Time Polymerase Chain Reaction (PCR)/ DNA Probe Hybridization

Reporting Name

Acanthamoeba species Detection, PCR

Specimen Type

Varies


Ordering Guidance


Although verification experiments did not detect Acanthamoeba species DNA in contact lenses from asymptomatic adults, it is possible that the polymerase chain reaction may detect asymptomatic colonization/contamination and, therefore, testing should not be performed on asymptomatic individuals.



Necessary Information


Specimen source is required.



Specimen Required


The preferred specimen for this test is corneal scraping or biopsy.

 

Submit only 1 of the following specimens:

 

Specimen Type: Tissue, fresh

Sources: Ocular

Container/Tube: Sterile container

Specimen Volume: 5-10 mm

Collection Instructions: Submit tissue in a sterile container with 1 mL of sterile saline, minimal essential media (MEM), or viral transport media.

 

Preferred Paraffin-Embedded Tissue Block:

Supplies: Tissue Block Container (T553)

Specimen Type: Formalin-fixed, paraffin-embedded tissue block (FFPE)

Sources: Ocular

Container/Tube: Tissue block

Collection Instructions: Submit a FFPE tissue block to be cut and returned.

 

Acceptable Paraffin-Embedded Tissue Block:

Specimen Type: FFPE section

Sources: Ocular

Container/Tube: Sterile container for each individual cut section (scroll).

Collection Instructions: Perform microtomy and prepare five separate 10-micron sections. Each section (scroll) must be placed in a separate sterile container for submission.

 

Specimen Type: Scrapings, swabs

Sources: Eye, ocular, cornea

Container/Tube: Sterile container

Specimen Volume: 1 mL

Collection Instructions:

1. Collect corneal scrapings using a scalpel or other sharp device to remove the outer layer of cells from the eye.

2. Swish the collection device in 1 mL of sterile saline, MEM, or viral transport media.

3. Remove the scalpel blade or sharp device from the collection container before submitting to the lab.

4. Specimens containing scalpel blades will be canceled.

5. If collected via swab, swab must be placed into viral transport media and submitted with the specimen. Specimens received without swabs will be canceled.

Additional Information: Swabs are not the preferred specimen for this test and may yield false-negative results.

 

Specimen Type: Contact lenses

Container/Tube: Sterile container

Specimen Volume: Entire collection

Collection Instructions:

1. Place entire contact lens in a sterile container with 1 mL sterile saline, viral transport media, or MEM.

2. Right and left lenses must be submitted individually using multiple sterile containers or in the original contact lens case. A separate order must be created for each lens being tested.

3. Indicate Right or Left in the specimen source.

 

Specimen Type: Contact lens cases without lenses

Container/Tube: Sterile container

Specimen Volume: 1 mL solution or entire case

Additional Information:

1. Depending on the type of case submitted, it may be necessary to test right and left chambers individually. A separate order must be created for each chamber being tested.

2. Indicate Right or Left in the specimen source.


Specimen Minimum Volume

Scrapings: 0.5 mL; Other specimen types: See Specimen Required

Specimen Stability Information

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

Reference Values

Negative

Interpretation

A positive result indicates the presence of Acanthamoeba species DNA and is consistent with active or recent infection. While positive results are highly specific indicators of disease, they should be correlated with symptoms, clinical findings, radiologic features, or confocal ophthalmologic examination.

Clinical Reference

1. Cope JR, Ali KM, Visvesvara GS: Pathogenic and opportunistic free-living amebae. In: Carroll KC, Pfaller MA, Landry ML, et al, eds. Manual of Clinical Microbiology. 12th Ed. ASM Press; 2019:chap142

2. Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Division of Foodborne, Waterborne, and Environmental Diseases (DFWED): Parasites - Acanthamoeba - Granulomatous Amebic Encephalitis (GAE); Keratitis. CDC; Updated December 29, 2021. Accessed March 28, 2023. Available at www.cdc.gov/parasites/acanthamoeba/health_professionals/acanthamoeba_keratitis_hcp.html

Day(s) Performed

Monday through Sunday

Report Available

2 to 3 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

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

87798

LOINC Code Information

Test ID Test Order Name Order LOINC Value
ACARP Acanthamoeba species Detection, PCR 41429-2

 

Result ID Test Result Name Result LOINC Value
SRCAS Specimen Source 31208-2
38058 Acanthamoeba species PCR 41429-2

Forms

If not ordering electronically, complete, print, and send a Microbiology Test Request (T244) with the specimen.