Detection Typhoid IgG IgM Rapid Test Reagent For Whole Blood Serum Plasma

Rapid And Efficient Detection Reagent For Typhoid Fever IgG/IgM

      The Typhoid IgG/IgM Rapid Test Device is a lateral flow immunoassay for the simultaneous detection and differentiation of anti-Salmonella typhi (S. typhi) IgG and IgM in human whole blood, serum or plasma.

Detection Principle

      The Typhoid IgG/IgM Rapid Test Device is a lateral flow chromatographic immunoassay. The test cassette consists of: 1) a burgundy colored conjugate pad containing recombinant S. typhoid H antigen and O antigen conjugated with colloid gold (Typhoid conjugates) and rabbit IgG-gold conjugates, 2) a nitrocellulose membrane strip containing two test bands (IgG and IgM bands) and a control band (C band). The IgM band is pre-coated with monoclonal anti-human IgM for the detection of IgM anti-S. typhi, IgG band is pre-coated with reagents for the detection of IgG anti-S. typhi , and the C band is pre-coated with goat anti rabbit IgG. When an adequate volume of test specimen is dispensed into the sample well of the cassette, the test specimen migrates by capillary action across the test cassette. Anti-S. typhi IgM if present in the patient specimen will bind to the Typhoid conjugates. The immunocomplex is then captured on the membrane by the pre-coated anti-human IgM antibody, forming a burgundy colored IgM band, indicating a S. typhi IgM positive test result. Anti-S. typhi IgG if present in the patient specimen will bind to the Typhoid conjugates. The immunocomplex is then captured by the pre-coated reagents on the membrane, forming a burgundy colored IgG band, indicating a S. typhi IgG positive test result. Absence of any test bands suggests a negative result. The test contains an internal control (C band) which should exhibit a burgundy colored band of the immunocomplex of goat anti rabbit IgG/rabbit IgG-gold conjugate regardless of the color development on any of the test bands. Otherwise, the test result is invalid and the specimen must be retested with another device.

SPECIMEN COLLECTION AND STORAGE

      All reagents are ready to use as supplied. Store unused test devices unopened at 2°C-30°C. The positive and negative controls should be kept at 2°C-8°C. If stored at 2°C-8°C, ensure that the test device is brought to room temperature before opening. The test device is stable through the expiration date printed on the sealed pouch. Do not freeze the kit or expose the kit over 30°C.

SPECIMEN COLLECTION AND HANDLING

• The Typhoid IgG/IgM Rapid Test Device (Whole Blood/Serum/Plasma) can be performed using whole blood (from venipuncture or fingerstick), serum or plasma. 
• To collect Fingerstick Whole Blood specimens: Wash the patient’s hand then allow to dry. Massage the hand without touching the puncture. Puncture the skin with a sterile lancet. Wipe away the first sign of blood. Gently rub the hand from wrist to palm to finger to form a rounded drop of blood over the puncture site. Add the Fingerstick Whole Blood specimen to the test device by using a capillary tube or hanging drops.
• Separate serum or plasma from blood as soon as possible to avoid hemolysis. Use only clear, non-hemolyzed specimens. 
• Testing should be performed immediately after specimen collection. Do not leave the specimens at room temperature for prolonged periods. Serum and plasma specimens may be stored at 2-8°C for up to 3 days. For long-term storage, specimens should be kept below -20°C. Whole blood collected by venipuncture should be stored at 2-8°C if the test is to be run within 2 days of collection. Do not freeze whole blood specimens. Whole blood collected by fingerstick should be tested immediately.
•  Bring specimens to room temperature prior to testing. Frozen specimens must be completely thawed and mixed well prior to testing. Specimens should not be frozen and thawed repeatedly.
•  If specimens are to be shipped, they should be packed in compliance with local regulations covering the transportation of etiologic agents.

ASSAY  PROCEDURE

Allow test device, specimen, buffer and/or controls to reach room temperature (15-30°C) prior to testing.

1. Bring the pouch to room temperature before opening it. Remove the test device from the sealed pouch and use it as soon as possible. 
2. Place the test device on a clean and level surface. For Whole Blood, Serum or Plasma specimens: Hold the dropper vertically and transfer 2 drops of specimen (or approximately 50 µL) to the specimen well (S) of the test device, then add 1 drop of buffer and start the timer. For Fingerstick Whole Blood specimens:

To use a capillary tube: Fill the capillary tube and transfer approximately 50 µL (or 2 drops) of fingerstick whole blood specimen to the specimen well (S) of the test device, then add 1 drop of buffer and start the timer. 

1. Wait for the colored line(s) to appear. Read results at 10 minutes. Do not interpret results after 20 minutes.

INTERPRETATION OF RESULTS

LIMITATIONS OF THE TEST

1. The Assay Procedure and the Test Result Interpretation must be followed closely when testing the presence of antibodies to S. typhi in serum or plasma from individual subjects. Failure to follow the procedure may give inaccurate results. 
2. The Typhoid IgG/IgM Rapid Test is limited to the qualitative detection of antibodies to S. typhi in human serum or plasma. The intensity of the test band does not have linear correlation with the antibody titer in the specimen.
3. The Typhoid IgG/IgM Rapid Test also detects para-typhi antibodies.
4.  A negative result for an individual subject indicates absence of detectable anti-S. typhi antibodies. However, a negative test result does not preclude the possibility of exposure to S. typhi.
5.  A negative result can occur if the quantity of anti-S. typhi antibodies present in the specimen is below the detection limit of the assay, or the antibodies that are detected are not present during the stage of disease in which a sample is collected.
6. If the symptom persists, while the result from Typhoid IgG/IgM Rapid Test is negative or nonreactive result, it is recommended to re-sample the patient few days late or test with an alternative test method, such as bacterial culture method.
7. Some specimens containing unusually high titer of heterophile antibodies or rheumatoid factor may affect expected results..

KIT COMPONENTS

• Test devices •
• Droppers 
• Buffer 
• Package insert

MATERIALS REQUIRED BUT NOT PROVIDED

• Specimen collection containers
• Lancets (for fingerstick whole blood only)
• Centrifuge
• Timer
• Heparinized capillary tubes and dispensing bulb (for fingerstick whole blood only)