A

 

The reason for using PPD-A is to differentiate NTM that share antigens with M. bovis. 

Therefore, if O.D. values for PPD-B and PPD-A are elevated, and the O.D. value is (B-A) ≤ 0.1, it is likely to be diagnosed as an NTM infection, not bTB. 

If both B-A > 0.1 and B-P > 0.1, it needs to be diagnosed as bTB.

 

A

 

This kit is used to diagnose bTB through a cellular immune response. Thus, if cattle have recently been treated with dexamethasone, delivered a calf, 

or contracted a disease that causes immunosuppression, these factors may inhibit IFN-γ responses to PPD antigens. 

 

Therefore, if cattle have been injected with dexamethasone within a week or if cattle have delivered the calf within 4 weeks, false-negative results can occur. 

For cattle that fall into these factors, it is recommended to re-collect the blood sample and re-test after taking some time before the ELISA.

 

A

 

Plasma sensitized by stimulating antigens for TB-Feron ELISA Plus kit can also be used in other ELISA kits in BIONOTE Inc. 

Tests such as BTB Ab ELISA, FMD NSP Ab ELISA, and B.Brucella Ab ELISA can all be performed using plasma samples sensitized with PBS.

 

A

 

This kit detects IFN-γ secreted by T lymphocytes exposed to M. bovis, the cause of bTB. 

Therefore, monoclonal antibodies specific to the bovine IFN-γ are used in this kit. 

Since the homology of IFN-γ proteins by species may be different, and there is no data evaluated on this kit for other species,

the results cannot be guaranteed if tests on other species are performed with this kit.

 

A

 

Typically, all cattle older than 6 months can be tested for IFN-γ assay. Since young calves under 6 months of age are still developing their immune systems, non-specific reactions may affect the results. 

In the Republic of Korea, an Article about the "Tuberculosis and Brucellosis Prevention Tips" states that cattle subject to bTB testing are 12 months old or older, 

and cattle that are 6 ~12 months can be tested if deemed necessary by livestock quarantine officers.

 

A

 

If you insert the ELISA plate into the ELISA reader, the reader reads the O.D. value using 450 nm (yellow) as the measurement wavelength and 620 nm (blue) as the reference wavelength. 

Then you will be able to calculate the final O.D. value by subtracting the O.D. value at 450 nm to the O.D. value at 620 nm. Reference wavelength is a concept that subtracts the default value, 

and the value read at 620 nm is usually very small. Therefore, if the ELISA reader cannot read 620nm, there is no significant difference in the result value when reading only using 450nm to check the results. 

 

However, if possible, the results should be calculated by reading both the measurement and reference wavelengths.

 

A

 

TMB substrate changes its color from being transparent to blue in response to enzymes contained in the enzyme conjugate. 

If you have not used TMB substrate yet but the blue color appears, the reagent in the bottle is considered to be contaminated and should not be used. 

Please note that putting back the used reagent into the reagent bottle after conducting the test can cause contamination. 

It is advised to only use the required amount of reagent from the reagent bottle, without putting it back.

 

A

 

Reusing the ELISA reagent reservoir that has been used in the other ELISA tests can affect the test results, as unwashed substances may be present. 

Please note that the reservoir is for one time use only, and a new reservoir must be used for each test.

 

A

 

If the collected plasma samples are not tested immediately, they can be stored at 2~8℃ for 7 days or at -20℃ for 2~3 months. 

However, before conducting the test, leave the stored sample at room temperature (18-25℃) for 15~30 minutes, and then vortex it.

 

A

 

Since the whole blood is treated with anticoagulant (heparin), blood cells can come up from the boundary between blood cells and plasma. 

The pipette tip should be located right on the surface of the plasma sample, carefully collecting the plasma until the boundary between blood cell and plasma. 

If blood cells inevitably get added, transfer to a separate tube and centrifuge again at 500 x g for 10 minutes to re-retrieve the supernatant fluid. 

Blood cells can react with TMB substrate and cause non-specific coloration.