Overview: Typhi Dot IgM TestIntroduction: The Typhi Dot IgM Test detects Salmonella Typhi IgM to diagnose typhoid fever, causing fever or fatigue. Following 2023 WHO guidelines, it uses immunoassays for high specificity, supporting infection screening. This test is critical for guiding diagnosis, treatment planning, and improving outcomes in immunology for patients with suspected typhoid fever.
Other Names: Typhi Dot IgM Assay, Salmonella Typhi IgM Test.
FDA Status: Laboratory-developed test (LDT), meeting immunology standards for diagnostic accuracy.
Historical Milestone: Typhoid IgM testing began in the 1990s with rapid diagnostic research. Immunoassay methods improved in the 2000s, enhancing diagnostic precision.
Purpose: Detects Salmonella Typhi IgM to diagnose typhoid fever, guides treatment, and evaluates patients with fever or fatigue.
Test Parameters: 1. Salmonella Typhi IgM Antibodies
Pretest Condition: No fasting required. Collect serum or saliva. Report history of fever, fatigue, or typhoid exposure.
Specimen: Serum (SST, 2-5 mL), Saliva (sterile container, 1-2 mL). Transport in a biohazard container.
Sample Stability at Room Temperature: 8 hours
Sample Stability at Refrigeration: 7 days
Sample Stability at Frozen: 6 months
Medical History: Document fever, fatigue, or history of typhoid exposure, especially in endemic areas. Include current medications, especially antibiotics.
Consent: Written consent required, detailing the tests purpose, typhoid fever implications, and risks of sample collection.
Procedural Considerations: Uses rapid dot-blot immunoassay to detect Salmonella Typhi IgM antibodies. Results are available in 1-2 days, supporting clinical decisions. Performed in laboratories, often for acute typhoid diagnosis.
Factors Affecting Result Accuracy: Sample hemolysis or improper storage can affect results. Early infection or antibiotic use may reduce sensitivity.
Clinical Significance: Positive IgM confirms acute typhoid fever, guiding antibiotic therapy like ceftriaxone. Negative results may require blood culture or PCR.
Specialist Consultation: Consult an infectious disease specialist for result interpretation and treatment planning.
Additional Supporting Tests: Blood culture, Widal test, or typhoid PCR to confirm typhoid fever diagnosis.
Test Limitations: Non-specific in early infection; clinical correlation is needed. Sample quality affects sensitivity.
References: WHO Typhoid Guidelines, 2023; Clinical Infectious Diseases, Parry CM, 2022.
