Intended Use

The Typhoid IgG/IgM Rapid Test is a lateral flow immunoassay for the simultaneous detection and differentiation of anti-Salmonella typhi (S. typhi)G and IgM in human serum or plasma. It is intended to be used as a screening test and as an aid in the  diagnosis of infection with S. typhi. Any reactive specimen with the  Typhoid IgG/IgM 2.0 Rapid Test must be confirmed with alternative testing method(s).

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 gallbladder. 
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 test^3,4.                                   
In contrast, the  Typhoid IgG/IgM Rapid Test 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.

Test Principle 

The Typhoid IgG/IgM Rapid Test 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 (M and G bands) and a control band (C band). The M band is pre-coated with monoclonal anti-human IgM for the detection of IgM anti-S. typhi, G 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. 

Quality Control

1.Internal Control:

This test contains a built-in control feature, the C band.  The C line develops after adding specimen and sample diluent. Otherwise, review the whole procedure and repeat test with a new device. 

2.External Control:

Good Laboratory Practice recommends using the external controls, positive and negative, to assure the proper performing of the assay, in particularly, under the following circumstances:

a.New operator uses the kit, prior to performing testing of specimen.

b. A new lot of test kit is used.

c.  A new shipment of kits is used.

d. The temperature used during storage of the kit fall outside of 2°C -30°C.

e. The temperature of the test area falls outside of 15°C -30°C.

Rebecca Yan 

Skype: span.biotech

Email: rebecca@spanbio.com

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www.spanbiotech.com