All IFA Reagents are universal within their test system and can be used independent of lot as long as the following are adhered to: The Product Number for the new reagent lot matches the proper Product Number for that test system, the reagent must have been stored in its required storage conditions and the new reagent is still within its expiration dating.
All test systems have been optimized utilizing the reagents provided in each test system. ZORBA® reagants are manufactured by ZEUS Scientific and optimized for our test systems only. Other manufacturer's reagents may not consist of the same reagents and formulation
The cut off to all IFA Test Systems is dependent on the initial dilution required by that specific test system Package Insert. Positivity at and above that initial starting dilution means that the patient sample is considered positive. A lack of fluorescence at the starting dilution means that the patient sample is negative. The cutoff is determined by a fluorescence grading system of 1 to 4+ (4+ being the strongest intensity of fluorescence while the 1+ is the weakest fluorescent staining that is considered significant). All positive control vials provide a manufacturer's suggested end point titer, or 1+ dilution, that can be used as a reference to judge minimally reactive, 1+ end point fluorescence. Anything equal to or above this fluorescence is positive while anything less intense is negative. Note: Due to laboratory environment, instrument variations & lab tech subjectivity, this 1+ dilution can only be considered a recommended dilution. It is fully acceptable for laboratories to show variance within +/- 1 serial dilution from the recommended.
The ZORBA® IgG Removal Reagent should be allowed to warm to room temperature before testing has been initiated. Prior to testing, the ZORBA® IgG Removal Reagent should be shaken well. Then a 1:10 screening dilution should be created by diluting 5uL of patient sera with 45uL of ZORBA® IgG Removal Reagent. The sample is now ready for screen testing. If the sample is to be further tittered, the serial dilutions should be made in PBS with the initial dilution being made in the ZORBA® IgG Removal Reagent as the starting dilution. Flocculent material may form due to immune complex formations. This material will not interfere with the test system yet can be removed by centrifugation prior to testing if desired.
ZORBA® Reagents are specifically geared toward removing interfering substances with patient sera to better prepare patient sera for optimal IFA testing conditions. The ZORBA-NS® Reagent was developed and optimized to reduce nonspecific fluorescence, resulting from the non-immunological attachment of immunoglobulins to a substrate. This effect may vary from sample to sample but if nonspecific interference is high within a sample, it can mask a potential pattern and would have to be reported as uninterpretable. Proactive use of this reagent will minimize retesting requirements for samples with high nonspecific concentrations. The ZORBA® IgG Removal Reagent was designed to functionally remove potentially interfering immunoglobulin G (IgG) antibodies from human sera prior to testing for IgM. Specific IgG in a patient specimen may compete with specific IgM for antigenic sites on the substrate. Depending on the ratio of IgG to IgM, false negative IgM results may be obtained. In addition, RF IgM (IgM class anti-IgG) if present in conjunction with specific IgG, may interact with the antigen bound IgG resulting in a false positive IgM test. Therefore accurate measurement of pathogen-specific IgM is highly dependent upon the effective removal or neutralization of specific IgG. Proactive use of this reagent will minimize this effect and provide more accurate testing results, meaning that further repeat and reference testing would be minimized as well.
ZORBA® IgG Removal Reagent should be used for pre-treatment when running IgM IFA Test Systems. ZORBA® NS Sample Diluent is not required for use on any particular test system, yet it should be used to reduce any possibility of conflicting sample related effects. Utilization of the ZORBA® Reagents will ensure that samples have been pretreated to the best of their ability; this will reduce both cost & product waste by minimizing the need to retest samples that contain the interfering substances.
A recommended endpoint titer refers to the last dilution that shows a measurable degree of reactivity. It is considered recommended because it was derived during the production of the Positive Control & it was the dilution that yielded a 1+, Minimally Reactive Result. This is the weakest fluorescence grade that is considered significant. Due to the subjectivity of the IFA Test Systems from differences in laboratory environments, instrumentation and laboratory technologist subjectivity, this endpoint titer may vary between laboratories. Therefore ZEUS Scientific recommends that each laboratory establish its own endpoint titer using the provided recommended endpoint titer as a reference. It has been found that most variation is still within 1+/- titer from the recommended endpoint titer, if it does not exactly match up with the recommended endpoint titer for that specific lab.
IFA Kits will be shipped in a specific configuration so that all reagents are grouped together. The amount of slides required for a particular day’s testing should be pulled and laid out on the lab bench, spread out from each other. If slides are allowed to remain grouped together, they will take longer to come to room temperature. Therefore, all slides should be laid out and allowed to come to room temperature evenly. Please note that slides should remain in their pouches until ready to add the diluted sample and controls.