Standard Operating Procedure for Widal Test

STANDARD OPERATING PROCEDURE (SOP): WIDAL AGGLUTINATION TEST

Document ID: [________________]
Effective Date: [________________]
Revision Number: [________________]
Department: Laboratory Services / Clinical Pathology

1. PURPOSE

The purpose of this Standard Operating Procedure (SOP) is to provide a standardized, accurate, and reproducible methodology for performing the Widal Agglutination Test to aid in the laboratory diagnosis of Typhoid and Paratyphoid fevers.

2. SCOPE

This procedure applies to all qualified laboratory personnel performing serological testing on patient serum samples at [_________________ Laboratory Name].

3. RESPONSIBILITY

The Laboratory Manager is responsible for ensuring compliance with this SOP. Laboratory Technicians are responsible for the precise execution of the test, documentation of results, and reporting to the requesting physician.

4. MATERIALS AND REAGENTS

• Reagents: Widal Antigens (Salmonella typhi 'O', 'H'; S. paratyphi 'AH', 'BH') obtained from [_________________ Manufacturer].
• Equipment: Centrifuge, Serological Pipettes, Test Tubes/Slide, Timer, Incubator (if required).
• Controls: Known Positive and Negative control sera.

5. PROCEDURE

5.1 Specimen Collection

• Patient Name: [_________________]
• Patient ID/MRN: [_________________]
• Collection Date/Time: [_________________]
• The specimen must be serum collected in a [_________________ tube type] and stored at [_________________ temperature] until testing.

5.2 Test Methodology (Slide/Tube)

1. Preparation: Bring all reagents to room temperature ([____]°C).
2. Slide Method (Screening):
   • Place [____] µL of patient serum onto the designated reaction circles.
   • Add one drop of each Widal antigen reagent to the corresponding circles.
   • Rotate the slide for [____] minutes.
   • Observe for agglutination under a high-intensity light source.
3. Tube Method (Confirmatory):
   • Prepare serial dilutions of patient serum in saline (e.g., 1:20, 1:40, 1:80, 1:160).
   • Add equal volumes of the respective antigens.
   • Incubate at [____]°C for [____] hours.
   • Read for the presence of a granular or flocculent deposit.

6. QUALITY CONTROL

• Positive Control Result: [_________________]
• Negative Control Result: [_________________]
• Lot Number of Reagents: [_________________]
• Expiry Date of Reagents: [_________________]

7. RECORDING AND REPORTING

Results shall be recorded as the highest dilution showing agglutination. Significant titers defined by the clinical director are:

• Typhi O: [_________________]
• Typhi H: [_________________]
• Paratyphi A/B: [_________________]

Observations/Discrepancies: [____________________________________________________________________]

8. AUTHORIZATION AND SIGNATURES

Prepared By:
Name: ___________________________
Title: ___________________________
Signature: ___________________________
Date: ___________________________

Reviewed and Approved By (Laboratory Director):
Name: ___________________________
Title: ___________________________
Signature: ___________________________
Date: ___________________________

Quality Assurance/Compliance Officer:
Name: ___________________________
Signature: ___________________________
Date: ___________________________