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**Overview**: Widal Slide Agglutination Test Panel**Introduction**: The Widal Slide Agglutination Test Panel is a diagnostic tool designed for typhoid fever screening using serum samples. In India, typhoid fever (Salmonella Typhi) causes ~1 million cases/year (higher in rural/low-SES with poor sanitation/water), presenting with prolonged fever, abdominal pain, and complications (intestinal perforation). High morbidity from under-testing leading to delayed ceftriaxone/azithromycin, progression to carrier state or mortality. Per microbiology practices aligned with ICMR, National Centre for Disease Control, and IDSP guidelines, the test employs immunoassay for Salmonella Typhi O/H and Paratyphi A/B antigens over 1â€"2 days with high accuracy, valuable for presumptive diagnosis in endemic areas (titre >1:160 or rising significant). This diagnostic falls under infectious disease screening and targets patients with prolonged fever or food/water exposure, addressing accurate detection to guide antibiotics. With elevated morbidity due to underdiagnosis, the test supports public health efforts by enabling rapid typhoid profiling and reducing transmission. Its serum-based approach ensures reliable agglutination detection.**Other Names**: Widal Slide Pnl.**FDA Status**: FDA approved, CLIA certified for biochemistry/immunology, compliant with 2025 standards.**Historical Milestone**: Widal slide test standard in typhoid endemic areas; in India, widely used despite limitations.**Purpose**: The test assesses 4 parameters including Salmonella Typhi O to guide typhoid fever screening, detect antibodies, inform antibiotics.**Test Parameters**: 1. Salmonella Typhi O, 2. Salmonella Typhi H, 3. Salmonella Paratyphi A, 4. Salmonella Paratyphi B.**Pretest Condition**: No fasting required; patients should have prolonged fever.**Specimen**: 3 mL serum in 1 SST, transported within specified times to maintain sample viability.**Sample Stability at Room Temperature**: 8 hours with proper handling to preserve antibody integrity, ensuring reliable test performance.**Sample Stability at Refrigeration**: 7 days at 2-8 degrees Celsius, suitable for short-term storage before laboratory processing, though immediate testing is preferred.**Sample Stability at Frozen**: 6 months at -20 degrees Celsius, allowing long-term storage for retesting, though freezing may affect some analytes.**Medical History**: Patients should provide details on fever duration, water source.**Consent**: Written informed consent is required, detailing the test's purpose, potential risks of untreated typhoid including perforation, benefits of screening, and minimal discomfort from venipuncture.**Procedural Considerations**: The test involves sample processing using immunoassay by trained personnel to ensure sterile technique, avoid hemolysis, and interpret results within 1â€"2 days using provided controls. Laboratories must maintain a controlled environment, adhere to quality assurance protocols.**Factors Affecting Result Accuracy**: Delays beyond stability periods, improper storage conditions, hemolysis can affect results. Correlation with clinical evaluation or additional testing is recommended to confirm findings.**Clinical Significance**: High titre (>1:160) or rising indicates typhoid, necessitating specialist input.**Specialist Consultation**: Infectious disease specialists should be consulted for management.**Additional Supporting Tests**: Blood culture, Typhidot for confirmation.**Test Limitations**: Cross-reactivity/vaccination interference; comprehensive approach required.**References**: Indian Journal of Medical Microbiology 2024, Typhoid Studies India 2023. |
