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Test Code SAM Entamoeba histolytica Antibody, Serum

Reporting Name

E. histolytica Ab, S

Useful For

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

 

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

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum


Advisory Information


Direct detection of Entamoeba histolytica in stool specimens is recommended to diagnose intestinal amebiasis. See OAP / Parasitic Examination or OAPNS / Ova and Parasite Exam, Non-Stool.



Shipping Instructions


 



Specimen Required


Container/Tube: 

Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL


Specimen Minimum Volume

0.15 mL

Specimen Stability Information

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

Reference Values

Negative

Reference values apply to all ages.

Day(s) and Time(s) Performed

Tuesday, Thursday; 9 a.m.

Test Classification

This test has been cleared or approved by the U.S. 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

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. Leukocytes, WBCs, and RBCs are found in the stools. Liver abscess can develop several weeks to months later producing hepatomegaly and fever.

 

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

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

Bruckner DA: Amebiasis. Clin Microbiol Rev 1992;5:356-369

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 sulphuric 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 ≥620 nm.(Package insert: RIDASCREEN Entamoeba histolytica IgG, R-Biopharm AG, Darmstadt, Germany, 06/10/2016)

Analytic Time

Same day/1 day

Specimen Retention Time

14 days

Reject Due To

Hemolysis

Mild OK; Gross reject

Lipemia

Mild OK; Gross reject

Icterus

NA

Other

NA

NY State Approved

Yes

Method Name

Enzyme-Linked Immunosorbent Assay (ELISA)

Forms

If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

Gastroenterology and Hepatology Test Request Form (T728) (http://www.mayomedicallaboratories.com/it-mmfiles/gastroenterology-and-hepatology-test-request.pdf)

Microbiology Test Request Form (T244) (http://www.mayomedicallaboratories.com/it-mmfiles/microbiology_test_request_form.pdf)