What aspects of testing should I check if I have a problem with results? ( 4 juillet 2013 )

Here is a trouble-shooting check-list:

 Did you correctly follow the instructions for use (incubation times, dilutions, number of washes, preparation of 1X solutions)?

 Has the washing system been properly maintained and regularly decontaminated?

 What water was used to prepare the wash solution? We recommend using water which is distilled or purified by reverse osmosis or a system such as MilliQ or Elga, which reduces the amount of bacteria in the water.

 Were any kit reagents inter-mixed or contaminated?

 Was the dishware clean?

 Was the substrate solution transparent before use?

 Has the kit expired?

 Were all reagents and components brought up to room temperature 18-25ºC before running the assay?

 What is the room temperature in the lab? It should be between 18-25ºC. As ELISA tests are sensitive to extreme temperature, avoid running the assay close to heating sources.

 Have you ensured that the pipettes are dispensing the correct volumes, and that the pipette tips are always tightly on before use?

 Did you read the plates at the correct wavelength?

 Were previously opened plates correctly stored? Please refer to Plate storage.pdf

 Were the storage conditions respected for all components, including any 1X solutions made from concentrated solutions? Please refer to Storage conditions.pdf.

Why do I obtain discordant results when I compare ELISA results with another serological technique? ( )

When comparing results obtained by methods based on different principles (ex. VNT vs. ELISA, IFI vs. ELISA, CFT vs. ELISA), it is practically impossible to obtain perfect test agreement, unless very strongly positive and perfectly negative samples are used.

This is also true when comparing cELISA and iELISA results. The polyclonal nature of serum means that it contains populations of IgGs with different affinities for different antigens, each antigen with many epitopes. Each technique detects these populations to a different extent. Sera close to the cut-off will show more discordant results, as they contain more limited quantities of each type of antibody.

What should I do if I have a problem with test results? ( )

Please contact IDvet or your sales representative immediately. Be sure to provide the following information:

  • Contact details of your lab
  • Kit product code and batch number, ex PARAS-4P, batch 344
  • Plate number, indicated on the short side of the microplate
  • Order date or purchase order number
  • Frequency of the problem:
    – Every run? From time to time?
    Since yesterday? Last week? Last month? Last batch?
  • OD results of the plate(s), indicating the position of the positive and negative controls
  • The clinical history of the animals tested (ex. clinical signs; from an infected or disease-free herd).

What should I do if I run out of liquid reagents (controls, conjugate, wash, stop or buffers)? ( )

  • IDvet provides additional liquid reagents free-of-charge, so that you may test all the plates you purchase.
  • Simply send your request to IDvet by email ( or fax (+33 4 67 45 36 95). 
  • Indicate the reference of the required component, which can be found on the label on the top of the box, and the number of vials you wish to receive. For example, for the wash solution batch 003, you should request the reference 15-003.
  • The material will be sent to you free-of-charge, while you will be asked to pay any freight charges.