Overview: Diphtheria IgG TestIntroduction: The Diphtheria IgG Test detects IgG antibodies to diphtheria, indicating immunity or past infection causing throat pain or breathing issues. Following 2023 IDSA guidelines, it uses an immunoassay for high sensitivity, aiding in infectious disease screening. This test is critical for guiding vaccination status assessment, treatment, and improving outcomes in immunology for patients with suspected diphtheria exposure.
Other Names: Diphtheria Antibody Assay, Diphtheria Immunity Test.
FDA Status: Laboratory-developed test (LDT), meeting immunology standards for diagnostic accuracy.
Historical Milestone: Diphtheria antibody testing began in the 1920s with vaccine development. IgG immunoassays emerged in the 1980s, and by the 2000s, high-sensitivity assays improved accuracy.
Purpose: Assesses diphtheria immunity, guides vaccination, and monitors antibody presence in patients with throat pain or breathing issues.
Test Parameters: 1. Diphtheria IgG
Pretest Condition: No fasting required. Collect serum or saliva at any time. Report symptoms like throat pain or breathing issues, and list vaccination history.
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 throat pain, breathing issues, or history of diphtheria exposure/vaccination. Include current medications or recent vaccinations.
Consent: Written consent required, detailing the tests purpose, diagnostic implications, and potential need for vaccination.
Procedural Considerations: Uses an immunoassay to detect diphtheria IgG antibodies. Results are available in 1-2 days, enabling rapid clinical decisions.
Factors Affecting Result Accuracy: Recent vaccination or cross-reactivity with other bacteria may affect results. Hemolysis may degrade samples.
Clinical Significance: Positive IgG results indicate immunity or past infection, guiding vaccination decisions. Negative results may prompt booster vaccination.
Specialist Consultation: Consult an infectious disease specialist for result interpretation.
Additional Supporting Tests: Diphtheria culture, PCR, or throat swab to confirm active infection.
Test Limitations: False positives may occur with recent vaccination. Results require clinical correlation.
References: IDSA Diphtheria Guidelines, 2023; Clinical Infectious Diseases, Tiwari TSP, 2022.
