Frequently Asked Questions

Frequently Asked Question on

Do EIA, ELISA, RIA, IFK and IHC kits and 125I-labeled peptides (tracers) have an expiration date?

Yes, the expiration date is clearly marked on the kit box label and/or the product insert. Product performance cannot be guaranteed past this date. For the best results we strongly recommend the kits to be used as soon as possible.

What are the storage conditions for immunology products?

The recommended storage temperature is stated on each product insert. Some kit components may require special storage condition, in which case they are placed in an additional small box displaying the storage condition for its content(s). All products should be stored in their original formats: we do not recommend storing them after they have been diluted.

How should I store my samples?

Samples need to be stored at -20 °C or below. Avoid repeated freeze and thaw cycles.

Can I modify the assay protocols for the immunoassay kits?

Our protocols have been optimized to provide the best kit performance. Modifications could yield different results than our QC data.

Can components from different EIA, ELISA, RIA, Immunofluorescence and Immunohistochemistry kits be used?

Each kit has been tested and optimized to give the best possible result with the specific set of components. Using components from other kits or sources is not recommended, because this could alter the kit performance

Do I have to run all of my standard and test samples in duplicate?

Duplicates are recommended for all samples, including standards, in order to increase confidence in the results.

Can I run one standard curve for multiple assay kits?

A separate standard curve should be run for each kit, even within the same lot. Kit-to-kit variability is often the consequence of technical errors or  different incubation/environmental conditions. In order to establish the validity of results, sample concentrations of analyte tested must be determined from a corresponding standard curve that is obtained under the very same conditions, i.e., simultaneously.

Can I store the diluted kit components and use them again?

We recommend that you use the diluted kit components within the time specified in the appropriate kit insert. We cannot guarantee the performance of the kit on a second or subsequent use since storing diluted kit components could result in suboptimal performance.

May I generate my own standard curve?

Yes. However, the range must not exceed the highest and the lowest concentrations that are specified for the kit used.

How many test samples will each immunoassay kit analyze?

EIA kits have sufficient reagents to run 40 samples in duplicates. RIA kits provide sufficient reagents to run up to 50 duplicate samples. The number of test samples will depend on the number of standards which need to be used for establishing the standard curve. The immunostaining kits (IFK and IHS) can run between 50 to 150 slides respectively depending on the dilution of the primary antibody.

Do I have to run all of my samples at one time?

We highly recommend running all the samples simultaneously. If you wish to use the kit only partially, please follow the recommended storage method as described in our product insert (however, we can not guarantee the optimal performance of our kits on any subsequent use). It is recommended to aliquot reagents in order to avoid repeated freezing and thawing.

What is the expected concentration level of a given analyte?

It is recommended to obtain the previously reported value levels from scientific literature databases, such as PubMed ( or High Wire (

What is the radioactivity level of RIA kit?

: Each RIA kit contains 1.5 μCi of 125I-labeled specific peptide.

What is the peptide-iodination schedule at Peninsula Laboratories?

Our iodination is performed every Monday and Tuesday every week. The specific peptides are labeled after we receive the orders.

Can I use the kit without allowing its components to reach room temperature?

For optimal performance we strongly recommend allowing all kit components to reach room temperature before running the assay. Larger volumes may need longer time to reach the ambient temperature.

Can I skip adding 500μL of assay buffer at the end of RIA protocol?

It is strongly recommended always to add the final 500μL of assay buffer and to vortex the tubes prior to centrifuging them.

Can I reduce the amount of the wash buffer?

Incomplete washing of the plate can impair the performance. While the volume which is stated in the insert is a recommended minimum, more wash buffer can be used without a risk.

Are the extraction materials, which are suggested in your extraction protocols, included in your kits?

No, the extraction materials are sold separately. They are available as an extraction kit, (cat.# S-5000), which contains 2 bottles of buffer A (washing buffer), 1 bottle of buffer B (elution buffer) and 1 pack of 50 Sepcolumns. The kit is sufficient for 50 samples. The buffers and columns are also sold as standalone products.

What is the best way to analyze my data?

We recommend the use of 4 parameter logistic (4-PL) or log-logit curve fitting software, which provides the line equation that best fits the data within a certain set of limitations. If the software is unavailable, the user can plot the data on a semi-log paper and calculate manually

How are the antibodies supplied?

Antibodies are supplied as undiluted, diluted or purified antiserum. While most antibodies are lyophilized, some are in dissolved form (please inquire directly for specific information). Individual product sheets provide detailed description of the material and are available upon request.

What antibody dilution should I use?

The working dilution of each antibody will depend on the intended application, and has to be determined by the end-user.

How should I store the antibodies?

Storage conditions are stated on each product sheet.

What are the requirements for collecting blood samples?

Blood must be collected and transferred into a non-heparinized polypropylene tube with EDTA (anticoagulant) and aprotinin (protease inhibitor).

Can your diluted antiserum for RIA or the antibody component of RIA/ EIA be also used for staining?

We do not recommend using these reagents for staining, because they have been diluted to the concentration which is optimal for the specific application.

What are the ordering requirements for radioactive products?

For orders of RIA kits and 125I-labeled peptides we require a copy of a valid radioactive materials handling license, showing the current shipping address. In addition, the RIA orders can only be processed after we receive a signed order confirmation (via fax).