Leptospira IgG

Bacterial/ Viral

Report in 48Hrs

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No Fasting Required

Details

Detects IgG antibodies in the blood against Leptospira bacteria, which cause leptospirosis

₹1,330₹1,650

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Leptospira IgG Test Information Guide

Why is it done?
- Detects IgG antibodies against Leptospira species, indicating past or current leptospirosis infection
- Confirms leptospirosis diagnosis in patients with clinical symptoms such as fever, headache, myalgia, and renal involvement
- Identifies chronic or convalescent phase infections when IgM levels have declined
- Performed typically 5-7 days after symptom onset, when IgG antibodies become detectable
- Assists in epidemiological surveys and determining immunity status in endemic areas
- Distinguishes recent infection from past exposure or vaccination
Normal Range
- Negative Result: Less than 1:400 or 1:800 (varies by laboratory method) Indicates no detectable IgG antibodies against Leptospira Suggests no prior infection or immunity
- Positive Result: 1:400 or higher (titers typically range 1:400 to 1:25,600) Indicates presence of IgG antibodies to Leptospira Suggests past or current infection, or post-vaccination immunity
- Units of Measurement: Titers (e.g., 1:100, 1:400, 1:800) or AU/mL (arbitrary units per milliliter) Results may be reported as optical density (OD) values in ELISA-based methods
- Interpretation: Normal (negative) indicates absence of recent or past Leptospira infection Abnormal (positive) indicates current or past infection with Leptospira species Note: IgG persists for years after infection, so positive results alone cannot determine timing of infection
Interpretation
- Negative IgG Result: Suggests no past or current Leptospira infection May indicate very early infection (before IgG develops, typically <5 days) Does not rule out acute leptospirosis if accompanied by positive IgM
- Positive IgG Result: Indicates past infection with subsequent immunity May indicate current/convalescent phase infection when paired with IgM May reflect vaccination status in vaccinated individuals Single positive result does not confirm acute infection
- Rising Titer (paired sera): Fourfold or greater increase between acute and convalescent samples Highly suggestive of current or recent Leptospira infection Considered diagnostic when paired with clinical presentation
- High Titer (≥1:1600): More consistent with current or recent infection May suggest acute phase illness, particularly when accompanied by positive IgM Higher titers correlate with recent exposure and active infection
- Factors Affecting Results: Timing of specimen collection relative to symptom onset Cross-reactivity with other spirochetes or serovars Previous vaccination or prior exposure history Immunocompromised status may show delayed or weak antibody response Laboratory methodology differences (ELISA, MAT, IFA)
Associated Organs
- Primary Organ Systems Affected: Kidneys (renal system) - most commonly affected Liver (hepatic system) - hepatitis and jaundice Lungs (respiratory system) - pulmonary hemorrhage possible Central nervous system - meningitis rare but serious Muscles and joints - myalgia and arthralgia common
- Diseases Diagnosed: Leptospirosis (bacterial infection caused by Leptospira interrogans and other species) Weil's disease (severe form with renal and hepatic failure) Anicteric leptospirosis (mild form without jaundice)
- Associated Conditions with Abnormal Results: Acute renal failure and chronic kidney disease Hepatic dysfunction and cirrhosis Pulmonary hemorrhage syndrome Aseptic meningitis Hemorrhagic fever with renal syndrome Myocarditis and arrhythmias Septic shock in severe cases
- Complications of Abnormal Results: Acute kidney injury requiring dialysis Hepatic necrosis and failure Respiratory distress requiring ventilatory support Bleeding manifestations and hemorrhage Multi-organ failure in severe leptospirosis Mortality rate 5-15% in Weil's disease if untreated
- Occupational Risk Groups: Agricultural workers exposed to contaminated water Abattoir workers and butchers Plumbers and sewer workers Military personnel in endemic regions Veterinarians and laboratory personnel
Follow-up Tests
- Confirmatory Tests: Leptospira IgM serology - to confirm acute phase infection Paired sera (acute and convalescent) - to document rising titers Microscopic agglutination test (MAT) - gold standard for serovar identification Leptospira culture - isolation from blood or urine (early and late disease) PCR testing - polymerase chain reaction for leptospiral DNA
- Organ Function Monitoring: Comprehensive metabolic panel (electrolytes, kidney function) Liver function tests (ALT, AST, bilirubin, albumin) Complete blood count (CBC) - assess thrombocytopenia and WBC abnormalities Coagulation studies (PT/INR, aPTT) if bleeding occurs Urinalysis and urine culture
- Additional Diagnostic Tests: Chest X-ray - evaluate for pulmonary involvement Renal ultrasound or CT - assess kidney damage Lumbar puncture and CSF analysis - if meningitis suspected Creatinine kinase (CK) - evaluate for rhabdomyolysis Procalcitonin or C-reactive protein - assess inflammatory response
- Monitoring Frequency: Daily monitoring of renal function and electrolytes during acute phase Weekly follow-up of kidney function for 4 weeks post-treatment Repeat IgG testing if initial result negative but clinical suspicion remains high (repeat after 5-7 days) Serial titers if diagnosis confirmation needed (paired sera 2 weeks apart) Long-term monitoring for chronic kidney disease if severe renal involvement occurred
- When Results are Positive: Initiate or continue antimicrobial therapy (doxycycline or penicillin) Order IgM serology to differentiate acute vs. chronic infection Refer to infectious disease specialist if severe manifestations present Isolate procedures follow standard precautions Notify public health authorities for epidemiological tracking
- When Results are Negative: Consider repeat testing if high clinical suspicion and early in disease course Order alternative diagnostic tests (blood culture, PCR) Evaluate for other bacterial causes of fever and organ dysfunction Consider other differential diagnoses based on clinical presentation
Fasting Required?
- Fasting Requirement: No - Fasting is NOT required for Leptospira IgG testing
- Dietary Restrictions: None - Patient may eat and drink normally before blood collection No special dietary modifications needed
- Medications: No medications need to be held or avoided before testing Antibiotic therapy may be continued during testing Immunosuppressive medications do not contraindicate testing
- Patient Preparation: No specific preparation needed Simple venipuncture to collect blood serum sample Approximately 5-10 mL of blood drawn into serum separator tube Sample transported to laboratory at room temperature or refrigerated per protocol Label sample with patient demographics and date/time of collection
- Timing Considerations: Optimal timing: 5-7 days or more after symptom onset (allows IgG antibody development) Can be drawn any time of day without time restrictions For paired sera: second sample collected 10-14 days after first sample Test results typically available within 24-48 hours depending on laboratory
- Special Instructions: Inform laboratory of clinical presentation and suspected leptospirosis diagnosis Provide complete travel and occupational exposure history Note any previous leptospirosis infections or vaccinations Specify if paired serology samples are being submitted Follow standard biosafety precautions for blood handling

How our test process works!