Widal Tube Test (24Hrs)

Bacterial/ Viral

Report in 12Hrs

At Home

No Fasting Required

Details

Detects Salmonella antibodies.

₹89₹127

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Widal Tube Test (24Hrs) - Comprehensive Medical Guide

Why is it done?
- Detects antibodies against Salmonella typhi and Salmonella paratyphi bacteria that cause enteric fever (typhoid and paratyphoid fever)
- Diagnoses suspected cases of typhoid fever presenting with prolonged fever, headache, abdominal pain, and rose spots rash
- Helps identify paratyphoid fever caused by Salmonella paratyphi A and B
- Typically performed during the second to third week of illness when antibody levels peak
- Used in endemic regions where typhoid fever is common; particularly valuable in areas with limited culture and molecular diagnostic facilities
- Provides rapid results (24 hours) for timely clinical decision-making and antibiotic therapy initiation
Normal Range
- Negative Result (Normal): O, H, and AH antibody titers < 1:80 (or absence of visible agglutination with standard antigen suspension)
- Positive Result (Abnormal): O (Somatic), H (Flagellar), or AH antibody titers ≥ 1:80 or higher indicating significant agglutination
- Tube Test Format: Results are reported as serial dilutions (1:40, 1:80, 1:160, 1:320, 1:640, 1:1280, etc.) showing clumping/agglutination visible to naked eye
- Four Antigens Tested: Salmonella typhi O (TyphO), Salmonella typhi H (TyphH), Salmonella paratyphi A (ParaA), and Salmonella paratyphi B (ParaB)
- Interpretation Cutoffs: 1:80 or greater is typically considered positive; however, single positive titer may require clinical correlation; four-fold rise in paired sera is diagnostic
Interpretation
- Strongly Positive Result (O ≥ 1:320 + H ≥ 1:160): Highly suggestive of acute typhoid fever; indicates active Salmonella typhi infection in second-third week of illness
- Moderately Positive Result (O 1:80-1:160 + H 1:40-1:80): Consistent with typhoid fever; clinical symptoms must be correlated; may represent early infection or vaccination response
- Rising H Titer Alone (O negative, H ≥ 1:80): May indicate early stage infection or chronic carrier state; less specific for active disease
- Paratyphoid Pattern (ParaA or ParaB elevation): Indicates paratyphoid fever; may occur simultaneously with mild typhi titers or independently
- Negative Result with Clinical Suspicion: Does not exclude typhoid; sensitivity only 60-80%; repeat testing in 3-5 days or pursue blood culture and molecular methods recommended
- Factors Affecting Results: Previous typhoid vaccination (may cause persistent H antibodies), chronic carriers (high baseline titers), immunocompromised patients (may have false negatives), sample taken too early in illness (< 1 week), previous exposure/partial immunity, antibiotic therapy (may suppress antibody response), and blood group A patients (naturally higher baseline levels)
- Four-Fold Rise in Paired Sera: Represents gold standard for diagnosis; samples taken 1-2 weeks apart showing 4x increase in titer confirms recent infection
- Regional Considerations: In endemic areas, higher baseline positive rates in general population due to past exposures; context of clinical presentation essential for interpretation
Associated Organs
- Primary Organ Systems Involved:
- Gastrointestinal Tract: Primary site of Salmonella invasion; causes inflammation, ulceration of Peyer's patches, and potential perforation in severe cases
- Immune System: Antibody production against somatic (O) and flagellar (H) antigens; reticuloendothelial system involvement; lymphoid tissue hyperplasia
- Hepatic System: Hepatosplenomegaly common; hepatitis with elevated transaminases; possible cholestasis
- Splenic System: Splenic enlargement; increased sequestration of infected cells; possible splenic infarction or rupture in severe disease
- Cardiovascular System: Myocarditis, bradycardia, hypotension, and possible cardiovascular collapse in severe systemic infection
- Central Nervous System: Typhoid encephalopathy, delirium, seizures, complications including coma in severe disease
- Diseases and Conditions Associated with Abnormal Results:
- Enteric (Typhoid) Fever: Systemic infection caused by Salmonella typhi; presents with sustained high fever, headache, weakness, abdominal distension, and rose spots rash
- Paratyphoid Fever: Less severe form caused by Salmonella paratyphi A and B; similar clinical presentation but typically milder course
- Chronic Typhoid Carrier State: Persistent Salmonella typhi in biliary tract; individuals continue to shed organisms; significant public health concern
- Potential Complications of Typhoid Fever:
- Intestinal Perforation: Life-threatening complication; occurs in terminal ileum; results in peritonitis and septic shock
- Pneumonia: Can occur as primary infection or secondary complication; poor prognostic indicator
- Meningitis: Salmonella meningitis associated with high morbidity and mortality; requires intensive treatment
- Myocarditis: Inflammation of heart muscle; can lead to cardiac dysfunction and arrhythmias
- Osteomyelitis and Arthritis: Extrapulmonary manifestations; Salmonella has tropism for bone and joint tissues
- Hepatic Abscess: Localized suppuration in liver; rare but serious complication requiring drainage
- Hemolytic Anemia: Can occur during acute infection; results in anemia requiring transfusion support
- Thrombocytopenia: Decreased platelet counts during infection; may lead to bleeding complications
Follow-up Tests
- Confirmatory Tests for Positive Widal Result:
- Blood Culture: Gold standard for diagnosing typhoid; should be performed before antibiotics; highest sensitivity in first week of illness
- Stool Culture: Recommended during 2nd-3rd week of illness; positive in 40-50% of cases; useful for identifying chronic carriers
- Urine Culture: Can be positive, especially in 3rd week onwards; may be helpful if blood and stool cultures negative
- PCR/Molecular Testing: Rapid molecular detection from blood samples; increasingly available; can detect Salmonella DNA within hours; superior sensitivity and specificity to Widal
- Repeat Widal Test (Paired Sera): If initial test negative but high clinical suspicion; second sample collected 10-14 days after first; four-fold rise in titer is diagnostic
- Laboratory Tests for Disease Monitoring:
- Complete Blood Count (CBC): Assess for leukopenia (common in typhoid), anemia, thrombocytopenia; perform at baseline and follow-up to monitor treatment response
- Liver Function Tests (LFTs): Monitor AST, ALT, bilirubin; hepatitis is common; perform initially and during treatment; resolution indicates improving condition
- Renal Function Tests (Creatinine, BUN): Assess for acute kidney injury; important in severe disease; baseline and periodic monitoring recommended
- Prothrombin Time (PT/INR): Monitor coagulation status; disseminated intravascular coagulation (DIC) may occur; important for assessing severity
- Imaging and Diagnostic Procedures:
- Abdominal Ultrasonography: If complications suspected; assess for hepatosplenomegaly, free fluid (perforation), hollow viscus dilation, abscesses
- Abdominal CT Scan: Superior imaging for complications; evaluates for perforation, abscess, splenic infarction; indicated if acute abdomen suspected
- Chest X-ray: Assess for pneumonia, pulmonary complications; obtain if respiratory symptoms develop
- Monitoring Frequency and Follow-up Schedule:
- Clinical monitoring: Daily during hospitalization; assess fever curve, abdominal symptoms, mental status, vital signs
- Laboratory repeat testing: Initial baseline labs, then every 3-5 days during acute phase, then weekly during convalescence
- Post-treatment follow-up: Repeat stool culture at 2-4 weeks post-treatment to rule out chronic carrier state
- Antibiotic Susceptibility Testing: Perform on cultured Salmonella isolates; essential for guiding appropriate antibiotic therapy and detecting resistance patterns (MDR, XDR strains)
Fasting Required?
- Fasting Status: NO - Fasting is NOT required for the Widal Tube Test
- Sample Collection Requirements:
- Specimen Type: Serum (blood without anticoagulant); minimal amount typically 3-5 mL required
- Collection Tube: Plain/gel separator tube (vacutainer/SST tube); NOT in EDTA (purple top) or other anticoagulant tubes
- Timing of Sample: Optimal during 2nd-3rd week of illness; earlier samples may show false negative; samples can be drawn any time of day
- Medications and Substances - NO Restrictions:
- No need to discontinue any medications before testing; no dietary restrictions required
- Alcohol: No restriction; does not affect test results
- Antibiotics: Should NOT be withheld before testing; if patient is already on antibiotics, note this on requisition as it may suppress antibody formation
- Physical Preparation:
- No specific physical preparation needed; standard venipuncture procedures apply
- Patient Positioning: Patient should be seated or lying down; drawing blood from standing patient increases hemolysis risk
- Stress Level: No specific stress management needed; standard anxiety reduction measures during phlebotomy
- Sample Handling and Processing:
- Allow blood to clot for 30 minutes at room temperature; centrifuge at 3000 rpm for 10 minutes to separate serum
- Serum must be clear and without hemolysis; refrigerate if testing cannot be done immediately
- Test Results Timeline: Results obtained within 24 hours (as indicated by '24Hrs' in test name); rapid turnaround crucial for clinical management
- Special Considerations:
- Vaccination History: Document recent typhoid vaccination; can cause elevated baseline antibody titers for months to years; essential for result interpretation
- Previous Typhoid History: Inform laboratory of prior typhoid infection; lifelong antibodies may persist affecting interpretation
- Immunocompromised Patients: May have false negative results due to impaired antibody response; blood culture should be prioritized; no special preparation needed but document immune status

How our test process works!