Troubleshooting & FAQs

  • Can the ELISA Protocol in the Product Insert be Modified?
    The assay protocol recommended in the kits' product insert have been developed with consideration given to typical limits of detection required i... read more
  • Custom Assay & Antibody Development Services
    As a recognized leader in bioprocess impurity analysis, Cygnus Technologies is pleased to offer its expertise to develop custom antibodies and assays.... read more
  • Calibration of HCP assays
    The absolute quantitation of HCP assays is exceedingly difficult for several reasons. First of all, there is no recognized reference preparation of HC... read more
  • How do I Maintain Quality Control of ELISA?
    We manufacture our kits for lot-to-lot consistency and restrict and evaluate changes in any components or procedures that could impact accuracy in the... read more
  • How do I Perform Protein A Sample Treatment Procedure?
    NOTE: This procedure only applies to our F400, F400Z and F050H kits, which require a boiling and centrifugation step. Be advised that Cygnus Technolog... read more
  • How do I Perform Spike & Recovery Studies?
    In some cases, your product or certain components in the product formulation buffer may interfere (either positive or negative interference) in the ab... read more
  • How do I Qualify HCP & Bioprocess Impurity Assays?
    This study protocol is suggested as an objective method to qualify that the Cygnus Technologies Host Cell Protein (HCP) ELISA kits and other bioproces... read more
  • What About Automation of Immunoassays?
    Many of our customers have expressed an interest in automating our ELISAs to improve throughput and assay performance. Cygnus Technologies has much ex... read more
  • What About Cross Reactivity of anti-HCP Antibodies to Drug Substances?
    There have been some erroneous reports in the literature of cross-reactivity of anti-HCP antibodies to recombinant drug substances. These mistaken con... read more
  • What are the Allowable Limits of HCP Impurities?
    We are not aware of limits of HCP impurities established by the FDA or any other international regulatory bodies. You should contact your regulatory b... read more
  • What are the best curve fitting routines for ELISA?
    We do not recommend the use of linear regression to fit ELISA data particularly HCP assays. We specifically warn against the use of linear regression ... read more
  • What Custom Services does Cygnus Provide?
    Scientists at Cygnus Technologies have many years of experience in developing immunochemical reagents and methods for analytical research and human an... read more
  • What is "High Dose Hook Effect"?
    For any ELISA to give accurate results there must be an excess of antibodies, both capture and enzyme conjugated, relative to the analyte being detect... read more
  • What is Matrix Interference?
    Assays attempting to measure trace contaminants such as HCPs often in the presence of more than a million-fold excess of the product, can be prone to ... read more
  • What is optimal, Process-Specific versus Generic/Platform/Multi-Use HCP Assays?
    Please review our technical article in the Publications section for our website for a very detailed discussion on the definitions, limitatio... read more
  • What is the difference in Sensitivity and Specificity of Western Blot vs ELISA?
    For lack of better methods, Western blot has been accepted by regulators as a method orthogonal to ELISA. Some companies have used WB to drive early p... read more
  • What is the Storage and Stability of ELISA Kits?
    Cygnus kits and reagents have been formulated to withstand shipment and/or temporary storage under ambient temperature conditions without any signific... read more
  • What Issues to Consider When Diluting Samples?
    Some samples, particularly those from upstream in your purification process will have impurity analyte concentrations above the analytical range of ou... read more
  • Which Cygnus CHO HCP kit to use: F1045, CM015, or F550-1?
    Cygnus currently offers 3 ELISA kits to measure CHO HCPs. Kit F1045, the CHO Lysate HCP ELISA Kit, 2G - replaces the first CHO Lysate kit (F015) devel... read more
  • Which Cygnus Insulin ELISA Kit to use, F040 or F280?
    Cygnus offers two ELISA kits to measure Insulin. Both kits use the same antibodies so immunological specificity is comparable. The major difference in... read more
  • Which Cygnus Protein A ELISA kit to use: F050H, F400, F400Z, F600 or F610?
    Cygnus Technologies now offers several ELISA kits for detection of natural Protein A as well as most modified recombinant constructs. Our or... read more
  • Which Sample Diluents should be used?
    Some samples, particularly those from upstream in your purification process will have impurity analyte concentrations above the analytical range of ou... read more
  • Why is Dilution Linearity important?
    Dilution linearity is a critical qualification experiment that should be performed on all downstream samples for which HCP impurity data is required. ... read more
  • Why Perform Dual Wavelength Analysis?
    The protocols in our ELISA kits recommend the use of dual wavelength analysis for microtiter plates readers appropriately equipped. For alkaline phosp... read more
  • How does MVP LRV data compare to live MVM spiking studies?
    Data from published manuscripts have shown that in the majority of parallel MVP vs. MVM experiments, LRV's of +/- 1.0 log10 are obtained.  One ca... read more
  • How can you ensure that the Spiking MVP is BSL-1 compatible?
    The Spiking MVP contained within the MockV MVM Kit is derived by recombinantly expressing the major capsid protein of live MVM.  Besides the sing... read more
  • Can this technique be used for predicting viral inactivation?
    Like live MVM, the Spiking MVP containing within the MockV MVM Kit is highly resistant to low pH inactivation techniques.  LRV’s of ≤ 1.0 hav... read more
  • How many experiments can I perform with the MockV MVM Kit?
    The MockV MVM Kit comes with 1.5 mL’s of Spiking MVP.  This is enough particle to challenge 10 loads of 150 mL’s each to a starting MVP conce... read more
  • How much MVP should I challenge my load with?
    For most chromatography experiments, it is recommended to target a spiked load concentration of 1.0 x 109 – 1.0 x 1010.  For nanofiltration exp... read more
  • What is the Immuno-qPCR assay’s LOQ?
    The current version of the MockV MVM Kit employs an Immuno-qPCR assay for MVP detection.  This assay is 10-100X more sensitive than standard ELIS... read more
  • What is the shelf life of the MVP?
    The Spiking MVP contained within the MockV MVM kit has shown to be stable for over 2 years at 4°C.  Data from Transmission Electron Microscopy a... read more
  • How can I ensure that my sample matrices will not interfere with the Immuno-qPCR assay?
    Prior to using the MockV MVM Kit as intended for purification spiking studies, an end-user is first recommended to conduct preliminary spike/recovery ... read more
  • When analyzing for assay interference, what spike/recovery percentages are acceptable?
    For normal ELISA spike/recovery, percentages of 50-150 or 50-200% are deemed acceptable.  The Immuno-qPCR assay performed as part of the MockV MV... read more
  • How should I store my experimental samples prior to Immuno-qPCR analysis?
    Similar to the spike/recovery preliminary study discussed above, it is recommended that the end-user perform a hold study prior to performing a purifi... read more
  • How should I clean my column after an MVP spiking experiment?
    In most cases, standard sodium hydroxide CIP steps are sufficient to denature MVP that remain bound to the resin or membrane.  A carry-over buffe... read more