Frequently asked questions of LPD Technical Services
Find answers to the questions most commonly asked of us.
If you have a question about the performance of an IDEXX test, your IDEXX representative requires certain information so that s/he can most efficiently assist you. Your answers to the questions such as these serve to quickly diagnose the performance issue:
- What is your company name and phone number?
- Which test kit are you using?
- What is the batch or serial number of the test kit?
- How many kits of the same batch or serial number do you have?
- What is the performance inquiry regarding? (e.g., unexpected results, invalid plate)
- Can you provide data to illustrate the problem?
- Have you used the kit more than once and, if so, was the same problem repeated?
When calling your representative with performance questions, please have relevant software version and test kit data available. This information helps us to quickly gather the information that we need. We appreciate your help in providing descriptive information and data that will help resolve your question quickly.
Follow these steps to download a certificate of analysis for an IDEXX test kit:
- In a web browser, go to https://www.idexx.com/livestock-poultry/certificates-of-analysis.html.
- Enter the lot number of the text kit. This is found on the outer kit label on the box.
- Select Request Certificate.
- Click on the test kit name to open the pdf file. You can then save the certificate to a location of your choice, or print it.
Follow these steps to download an MSDS for an IDEXX test kit:
- In a web browser, go to https://www.idexx.com/corporate/common/msds.html.
- Select the Product Family and Language.
- Enter the product name or part number.
- Click Find (M)SDS; a list of matching MSDS pdf files will be displayed.
- Click on the test kit name to open the pdf file. You can then save the sheet to a location of your choice, or print it.
You may have noticed that after you contact LPD Technical Service, IDEXX sends a survey asking about your interaction with the LPD team. Here’s why: IDEXX is certified to ISO standards. Our continued ISO certification depends on monitoring the satisfaction of our customers.
We realize that many of you have close relationships with your LPD Technical Services representatives and readily communicate your needs to them, but it is important for us to hear from you through other means as well. That’s why we always send a follow-up survey after our customers contact IDEXX Technical Services.
If you receive an e-mail survey, please take a minute to answer the few questions about your recent experience with LPD Technical Services. Your feedback helps us provide the outstanding products, service and support that you expect from IDEXX.
IDEXX has some ELISA assays that use a dual-well format. Dual-well assays require two wells to be used for each sample. One well is coated with virus antigen and the other well is coated with NHC antigens, which are derived from noninfected cells.
The NHC well is used to assess the extent of normal host cell contribution to the total signal by relating the reactivity in the viral antigen well to the reactivity in the NHC well. If the NHC well was not present, any nonspecific reactivity in the antigen well could result in a false-positive.
After subtracting the NHC signal from the antigen signal, you will be left with signal directly related to the presence of antibodies. One then follows the specific insert interpretation to classify the result as positive or negative.
Yes. Milk samples with common preservatives, such as Bronopol and sodium azide, can be used in IDEXX milk tests with no adverse effects. Always review the test insert for detailed sample requirements.
Many Dairy Herd Information Association laboratories use a low-temperature heat treatment. Comparisons of tests performed with both heat-treated and non-heat-treated samples show no significant difference in performance. Always review the test insert for detailed sample requirements.
Whole-milk samples can be used after centrifugation for 15 minutes at 2000 xg, or after overnight refrigeration at 2ºC–8ºC. The sample should be drawn from below the cream layer. This sampling practice can vary around the globe, with some regions thoroughly mixing the whole milk and then drawing the sample. Refer to the test insert to determine whether the test has any restrictions when using whole-milk samples. Always review the test insert for detailed sample requirements.
Can curdled or sour milk samples be used in ELISA testing?
Curdled or sour milk should not be used. The matrix is difficult to pipette, and any residue left after washing may cause false-positive results. Always review the test insert for detailed sample requirements.
Unless the test kit insert states that testing is for multiple species or different sample types, IDEXX does not have that specific claim and cannot stand behind results obtained from off-insert testing. To have a specific claim, we need to have supporting data and approval by different governing bodies. Often during the development process, alternate sample types or species are not evaluated, so we are unable to make those claims in our insert. When in doubt, check your test kit insert or call your local IDEXX representative.
IDEXX stands behind the results generated until the test kit expiration date is reached. Use of a test after the expiration date is not advised, even if the individual components making up the test kit may not yet have expired. Due to government regulations and for quality control purposes, we must abide by the expiration date on the test kit box.
Initially, several lots of individual components making up a test kit are tested individually to see performance over the long term. From this multiple-lot testing, the component is given a certain expiration date. Then, to determine the expiration date of the kit, there is multiple-lot testing on the entire kit. This testing may show good performance past, for example a 12-month expiration date, but to ensure the highest quality product throughout the life of the test kit, we may not give it the additional dating noted by the other components. Lastly, we are regulated on a kit-by-kit basis by our outline of productions with agencies, such as the USDA, which specifies the allowable expiration dates for each kit.
The kit insert specifies the wavelength required for an assay. Most assays specify the absorbance reading at 450 nm or 650 nm. Other filters can be used, but will result in lower optical density (OD) values. The use of 630-nm or 620-nm filter instead of a 650nm filter will lower the OD values of both the controls and samples, but will do so equivalently across the entire plate. The use of these alternative filters will not affect the test results.
Small-volume testing can produce a strain on some reagents. In these situations, it is recommended to portion out plate strips into other sealed bags with a desiccant, or aliquot the conjugate into small vessels for use. Keep the unused vessels or plates in the refrigerator and take out only what is needed for each day’s testing. Be sure to label all bags and vials with the reagent part and batch number, as well as the test kit name its corresponding batch number.
Maintenance and calibration of all laboratory equipment is essential for accurate and reproducible results. Maintenance routines depend upon the amount of daily testing performed in your laboratory. Always refer to your equipment manufacturer’s guide for their recommendations. You can also contact your LPD Technical Service representative for any guidance/documentation on specific instruments and calibration plate availability for microtiter plate readers.
The xChekPlus software does allow the user to customize reports to show the laboratory name. Choose Options > Report Configuration. The Header tab gives you four lines on which to place your laboratory’s name and address. Once you enter your laboratory’s information here, it will always be seen on saved and printed xChekPlus reports.
When creating an Analyze Case Report, the final screen that appears before the report is generated (the Analyze Cases Report - Options dialog box) allows you to choose your case and graph options. On the right-hand side is the Variables button. Click the Variables button to see a list of variables that can be shown on the report. Check the box next to the variable you want to display on the report, such as “Calendar Age.” You will also see the Variables button in other screens when creating other reports, and in Plate View after reading a plate.
Follow these steps to change the orientation of the controls on a template for an assay:
- From the main screen, choose Database > Assays.
- Select the specific species and test.
- In the Manage Assays dialog box, on the right side, is Template; select the orientation you prefer from the dropdown list. This will now be the default orientation for the controls.
Kit lot numbers and expiration dates can be entered in two places in the xChekPlus software.
- Lot number information can be entered in Plate View after reading your plate by double-clicking the Kit or Expiration Date field. Entering the information this way will apply it only to this data set.
- By choosing Database > Assays and selecting the specific test, you can also enter the kit lot and expiration date information. If entered this way, the information will be applied to all testing until a new lot and expiration date are added.
Note: This information can be entered each time an assay is run or–if you will be running the same lot number for several tests in a row–it can be entered into the database assay information.