Scrub typhus IgG and IgM by Immunochromatography

Bacterial/ Viral

Report in 4Hrs

At Home

No Fasting Required

Details

Rapid antibody test.

₹370₹529

30% OFF

Scrub Typhus IgG and IgM by Immunochromatography - Comprehensive Test Guide

Why is it done?
- Test Purpose: Detects antibodies (IgG and IgM) against Orientia tsutsugamushi, the causative agent of scrub typhus, a rickettsial infection transmitted by chigger mites in the Asia-Pacific region.
- Primary Indications: Fever of unknown origin in endemic areas; suspected rickettsial infection; evaluation of undifferentiated febrile illness; endemic typhus fever; differential diagnosis of fever with eschar or maculopapular rash.
- Clinical Presentation: Performed when patients present with fever, headache, myalgia, rash, or characteristic eschar (black necrotic lesion) at site of chigger bite.
- Timing: Preferably during acute phase of illness (5-7 days after symptom onset); IgM typically appears first, followed by IgG; most useful after first week of fever.
- Geographic Relevance: Particularly important for individuals in endemic regions including India, Southeast Asia, China, Japan, and the Western Pacific region.
Normal Range
- Reference Values: Negative (Non-Reactive) for both IgG and IgM antibodies
- Units of Measurement: Qualitative (Positive/Negative); Some laboratories report as Non-Reactive, Weakly Reactive, or Strongly Reactive; may include index values or optical density measurements.
- IgM Interpretation: Negative = No IgM antibodies detected; Positive = Recent or acute infection (appears 5-7 days after symptom onset)
- IgG Interpretation: Negative = No IgG antibodies detected; Positive = Past infection or chronic/recovery phase (may persist for years after infection)
- Normal vs Abnormal: Normal = Both IgM and IgG negative (Non-reactive); Abnormal = One or both antibodies positive (Reactive), indicating current or prior scrub typhus infection
- Borderline Values: Weakly reactive or equivocal results may require repeat testing or confirmation with alternative methods; clinical correlation is essential.
Interpretation
- IgM Positive, IgG Negative: Indicates acute scrub typhus infection; suggests primary immune response occurring within first 1-2 weeks of illness; most reliable for acute diagnosis.
- IgM Positive, IgG Positive: Indicates acute or recent scrub typhus in later stages (2-4 weeks of illness); suggests both primary and secondary immune response; consistent with ongoing or recent infection.
- IgM Negative, IgG Positive: Indicates past or previous scrub typhus infection; suggests recovery phase or previous exposure; may represent chronic or latent infection; careful clinical correlation needed.
- Both IgM and IgG Negative: No serological evidence of scrub typhus infection; rules out scrub typhus unless tested too early (before day 5-7 of illness); consider other differential diagnoses.
- Factors Affecting Results: Timing of sample collection (early illness may have false negatives); immunosuppression; strain variation of Orientia tsutsugamushi; prior infections or vaccinations; hemolysis or contaminated samples; use of antibiotics before testing.
- Clinical Sensitivity and Specificity: Immunochromatography typically shows 75-90% sensitivity and 85-95% specificity; higher sensitivity when tested after day 7 of illness; specificity improves with combined IgM and IgG results.
- Cross-reactivity Concerns: Possible cross-reactivity with other rickettsial infections (murine typhus, endemic typhus); consider clinical context and geographic exposure when interpreting results.
Associated Organs
- Primary Organ Systems: Immune system (serology test); skin (eschar formation at bite site); vascular system (vasculitis); multiple organ systems in disseminated disease.
- Cardiovascular Involvement: Myocarditis, pericarditis, congestive heart failure in severe cases; vasculitis affecting coronary vessels; hypotension and shock in complicated infections.
- Pulmonary Involvement: Acute respiratory distress syndrome (ARDS); pneumonitis; pulmonary edema; interstitial lung disease; respiratory failure in severe disease.
- Central Nervous System: Meningitis; encephalitis; seizures; confusion and altered mental status; complications associated with vasculitis and inflammation.
- Renal Involvement: Acute kidney injury; glomerulonephritis; proteinuria; elevated creatinine in severe or disseminated disease.
- Hepatic Involvement: Hepatitis; elevated liver enzymes; hepatomegaly; jaundice in severe cases; reduced synthetic function in advanced disease.
- Hematologic Complications: Thrombocytopenia (commonly observed); leukopenia; anemia; disseminated intravascular coagulation (DIC) in severe cases.
- Cutaneous Manifestations: Characteristic eschar (necrotic lesion); maculopapular rash; petechial rash in severe disease; skin necrosis in disseminated disease.
- Associated Diseases: Classic scrub typhus; Japanese river fever; tsutsugamushi disease; atypical fever presentations; severe scrub typhus with multi-organ failure.
Follow-up Tests
- Confirmatory Tests: Indirect immunofluorescence assay (IFA) for definitive confirmation; Western blot for strain identification; nested PCR for pathogen detection in early phase.
- Repeat Serology: Repeat testing 1-2 weeks after initial test if clinical suspicion remains high and first test is negative (early illness); paired sera for four-fold rise in titer confirm acute infection.
- Organ-specific Assessments: Complete blood count (CBC) for thrombocytopenia and leukopenia; liver function tests; renal function tests; coagulation profile; chest X-ray for pulmonary involvement.
- Cardiac Monitoring: Electrocardiogram (ECG); troponin levels; echocardiography if myocarditis suspected; continuous cardiac monitoring for severe cases.
- Neuroimaging: MRI or CT of brain if neurological symptoms present; lumbar puncture with cerebrospinal fluid analysis if meningitis suspected.
- Molecular Testing: PCR or RT-PCR for direct detection of Orientia tsutsugamushi in blood or tissue samples; particularly useful in early phase or immunocompromised patients.
- Differential Diagnosis Tests: Typhoid serology (Widal test); dengue serology; leptospirosis serology; malaria smear and antigen detection; rickettsia spotted fever serology.
- Monitoring Frequency: Acute phase: daily clinical assessment and laboratory monitoring; recovery phase: repeat tests as clinically indicated; follow-up at 2-4 weeks for complicated cases.
- Treatment Response Monitoring: Clinical response to doxycycline or other antibiotics; fever resolution; laboratory parameter normalization; imaging studies for complications.
Fasting Required?
- Fasting Status: No - Fasting is NOT required for this serology test
- Sample Collection: Blood sample (serum) collected via venipuncture; typically 3-5 mL of blood in a serum separator tube; can be collected at any time of day.
- Medications: No medications need to be avoided before this test; continue all routine medications as prescribed; antibiotic therapy does not interfere with serology.
- Patient Preparation: No special preparation needed; normal daily activities permitted; adequate hydration recommended to facilitate blood draw; patient can eat and drink normally before testing.
- Timing Considerations: Optimal collection 5-7 days after symptom onset; earlier collection may result in false negative; timing is more important than fasting status.
- Sample Handling: Allow blood to clot at room temperature; centrifuge to separate serum; store at 2-8°C if testing delayed; do not freeze before separation unless instructed.
- Special Instructions: Inform laboratory of acute febrile illness; provide travel history to endemic areas; note antibiotic therapy timeline; avoid contamination during collection.

How our test process works!