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Epic Code LAB766 Entamoeba histolytica Antibody, Serum

Additional Codes

Mayo Code: SAM

Epic Code: LAB 766

Interface Order Alias: 10365

Cerner code: 4306

Reporting Name

E. histolytica Ab, S

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Clinical Information

Amebiasis is an infection by the protozoan parasite, Entamoeba histolytica. The infection is acquired by ingestion of cysts in fecally contaminated food or water; excystation and infection occur in the large intestine. After excystation, trophozoites attach to the intestinal wall and liberate extracellular enzymes that enable invasion of the mucosa and spread to other organs, especially the liver and lung where abscesses develop.

 

Amebiasis (or amebic dysentery) can cause bloody diarrhea accompanied by fever and prostration. White and red blood cells are found in the stool. Liver abscess can develop several weeks to months later producing hepatomegaly and fever.

 

Pathogenic (E histolytica) and nonpathogenic (Entamoeba dispar) species of Entamoeba occur. Additionally, some of those infected with pathogenic strains are asymptomatic cyst carriers.

 

Serology may be particularly useful in supporting the diagnosis of amebic liver abscess in patients without a definite history of intestinal amebiasis and who have not spent substantial periods of time in endemic areas.

Useful For

As an adjunct in the diagnosis of extraintestinal amebiasis, especially liver abscess

Specimen Type

Serum


Ordering Guidance


Direct detection of Entamoeba histolytica in fecal specimens is recommended to diagnose intestinal amebiasis. See OAP / Ova and Parasite, Concentrate and Permanent Smear, Microscopy, Feces or OAPNS / Ova and Parasite, Microscopy, Varies.



Shipping Instructions


 



Specimen Required


Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL


Laboratory Test Directory Note:

COLLECTION NOTE: Volumes listed are in serum or plasma, draw approximately 2 1/2 times the requested volume in whole blood.

Specimen Minimum Volume

0.15 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Frozen (preferred) 30 days
  Refrigerated  7 days

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject

Day(s) Performed

Tuesday, Thursday

Reference Values

Negative

Reference values apply to all ages.

Interpretation

A positive result suggests current or previous infection with Entamoeba histolytica.

 

Since pathogenic and nonpathogenic species of Entamoeba cannot be differentiated microscopically, some authorities believe a positive serology indicates the presence of the pathogenic species (ie, E histolytica).

Cautions

Previous episodes of intestinal amebiasis may produce a positive serology.

 

Serologic results should be used as an aid in diagnosis and should not be interpreted as diagnostic by themselves.

Clinical Reference

1. Bruckner DA: Amebiasis. Clin Microbiol Rev. 1992 Oct;5(4):356-369. doi: 10.1128/CMR.5.4.356

2. Petri WA, Haque R, Moonah SN: Entamoeba species, including amebic colitis and liver abscess. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Elsevier; 2020:3273-3286

Method Name

Enzyme-Linked Immunosorbent Assay (ELISA)

Method Description

Purified antigens are coated to a microwell plate. Antibodies in the patient samples bind to the antigens and are determined during the second step by using enzyme-labelled protein A (the conjugate). The enzyme converts the colorless substrate (urea peroxide/TMB) to a blue end product. The enzyme reaction is stopped by adding sulfuric acid and the colour of the mixture switches from blue to yellow at the same time. The final measurement is carried out at 450 nm on a photometer using a reference wavelength greater than or equal to 620 nm.(Package insert: RIDASCREEN Entamoeba histolytica IgG. R-Biopharm AG; 07/10/2019)

Report Available

Same day/1 to 5 days

Test Classification

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

86753

LOINC Code Information

Test ID Test Order Name Order LOINC Value
SAM E. histolytica Ab, S 22285-1

 

Result ID Test Result Name Result LOINC Value
9049 E. histolytica Ab, S 22285-1

Forms

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