Overview: Amoebic Serology IgG TestIntroduction: The Amoebic Serology IgG Test detects IgG antibodies to amoeba, indicating infection like amoebic dysentery, which causes diarrhea, abdominal pain, or liver abscess. Following 2023 IDSA guidelines, it uses an immunoassay for high sensitivity, aiding in infectious disease screening. This test is critical for guiding treatment, monitoring infection, and improving outcomes in serology for patients with suspected amoebiasis.
Other Names: Amoebic IgG Assay, Entamoeba histolytica IgG Test.
FDA Status: Laboratory-developed test (LDT), meeting serology standards for diagnostic accuracy.
Historical Milestone: Amoebic serology began in the 1970s with agglutination tests. IgG immunoassays emerged in the 1980s, and by the 2000s, enzyme-linked assays improved detection of amoebic infections.
Purpose: Diagnoses amoebic infections, guides treatment, and monitors disease in patients with symptoms like diarrhea, abdominal pain, or liver abscess.
Test Parameters: 1. Amoebic IgG
Pretest Condition: No fasting required. Collect serum or saliva at any time, ideally after symptom onset. Report symptoms like diarrhea or abdominal pain, and list medications like metronidazole.
Specimen: 2-5 mL serum (SST) or 1-2 mL saliva (sterile container). Centrifuge serum within 1 hour. Transport in a biohazard bag within 8 hours.
Sample Stability at Room Temperature: 8 hours
Sample Stability at Refrigeration: 7 days
Sample Stability at Frozen: 6 months
Medical History: Document symptoms, travel history to endemic areas, or family history of parasitic infections. Include current medications, especially antiparasitic drugs.
Consent: Written consent required, detailing the tests purpose, diagnostic implications, and potential need for treatment or imaging.
Procedural Considerations: Uses an immunoassay to measure amoebic IgG. Results are available in 1-2 days, enabling rapid clinical decisions.
Factors Affecting Result Accuracy: Recent antiparasitic treatment may suppress antibody levels, causing false negatives. Hemolysis or improper storage can degrade samples.
Clinical Significance: Elevated IgG levels confirm amoebic infection, prompting antiparasitic therapy. Normal levels may require stool antigen testing for confirmation.
Specialist Consultation: Consult an infectious disease specialist for result interpretation. A gastroenterologist referral is advised for liver abscess cases.
Additional Supporting Tests: Stool antigen test, liver ultrasound, or amoebic PCR to confirm amoebic infection or assess complications.
Test Limitations: False negatives may occur with early infection or treatment. Cross-reactivity with other parasites requires clinical correlation.
References: IDSA Amoebiasis Guidelines, 2023; Clinical Infectious Diseases, Fotedar R, 2022.
