The reagent self-agglutinates before testing the serum.
The reagent should be shaken gently and thoroughly before use and regularly during use, particularly if it has been stored for a long time. If self-agglutination is observed, shake the bottle for a few more minutes and make sure there is no deposit at the bottom of the bottle.
I have almost finished my antigen bottle and have problems with sensitivity. Some of my results are positive when they should be negative.
There are two possible explanations:
1-Repeated use of the same bottle including a large number of thermal cycles (“storage in a cool place – use at room temperature”) over a long period of time will reduce the longevity of the product and is not recommended. The bottle should be used within a month of opening.
2 The reagent should be shaken gently and thoroughly before use and regularly during use, particularly if it has been stored for a long time. If self-agglutination is observed, shake the bottle for a few more minutes and make sure there is no deposit at the bottom of the bottle.
My positive control serum doesn’t react after 1:5 dilution.
The positive Mycoplasma or Salmonella control sera should be used for testing without being diluted. If the rapid plate agglutination test is positive, only the sera taken in the field should be diluted and heated.
The serum samples are not clear. What should I do?
To clarify the serum, centrifuge it between 800 and 1200 g (between 7500 and 12000 m s-2) for 10 to 15 minutes and, if possible, at a temperature of 5 ±3 °C.
However, if the serum has haemolysed or is not clean enough, it cannot be interpreted and must be rejected.
It may be useful to remind the people who actually take the samples to use blood collection tubes without anticoagulant.
The mixture is positive although the individual reagents that make up this mixture are all negative.
Our mixtures are intended to be used as initial rapid screening tests.
If a strain doesn’t react with the mixture, there is no need to test the individual reagents.
If agglutination does occur, the individual tests should be performed as follows:
1-If one of the individual reagents gives positive results with the strain, this strain has the serotype of the reagent;
2-If no individual reagent gives positive results, the strain is non-typeable with the tested reagents.
My strain reacts with both individual reagents:
In case of cross reactivity, perform the test with a dense suspension (optic density between 1.4 and 1.8, at a 580nm wavelength. This is equivalent to 3 on the Mac Farland scale). Mixing takes 2 minutes instead of 30 seconds.
Agglutination time may be longer if the test is performed with diluted suspensions. If cross reactivity is still observed. The serotype of the strain is the one for which agglutinates appear first.