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.
SUMMARY AND EXPLANATION OF THE TEST
Typhoid fever is caused by S. typhi, a Gram-negative bacterium. World-wide an estimated 17 million
cases and 600,000 associated deaths occur annually1. Patients who
are infected with HIV are at significantly increased risk of
clinical infection with S. typhi2. Evidence of H. pylori infection
also presents an increase risk of acquiring typhoid fever. 1-5% of
patients become chronic carrier harboring S. typhi in the
The clinical diagnosis of typhoid fever depends on the isolation of S. typhi from blood, bone marrow
or a specific anatomic lesion. In the facilities that can not
afford to perform this complicated and time-consuming procedure,
Filix-Widal test is used to facilitate the diagnosis. However, many
limitations lead to difficulties in the interpretation of the Widal
In contrast, the Typhoid IgG/IgM Rapid Test Device is a simple and rapid laboratory test.
The test simultaneously detects and differentiates the IgG and the
IgM antibodies to S. typhi specific antigen5 thus to aid in the
determination of current or previous exposure to the S. typhi.
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.
REAGENTS AND MATERIALS PROVIDED
1. 25 Test Device with 25 dropper
3.One package insert (instruction for use)
MATERIALS REQUIRED BUT NOT PROVIDED
Clock or Timer
WARNINGS AND PRECAUTUIONS
1.Do not use after expiration date indicated on the package. Do not
use the test if its foil pouch is damaged. Do not reuse tests.
2.The products should be treated as potentially infectious, and
handled observing the usual safety precautions (do not ingest or
3.Avoid cross-contamination of specimens by using a new specimen
collection container for each specimen obtained.
4.Do not eat, drink or smoke in the area where the specimens and
kits are handled. Handle all specimens as if they contain
infectious agents. Observe established precautions against
microbiological hazards throughout the procedure and follow the
standard procedures for proper disposal of specimens. Wear
protective clothing such as laboratory coats, disposable gloves and
eye protection when specimens are assayed.
5.Do not interchange or mix reagents from different lots.
6.Humidity and temperature can adversely affect results.
7.The used testing materials should be discarded in accordance with
local, state and/or federal regulations.