CA242 ELISA Kit

Catalog No. L5E1012

(96 tests)

FOR RESEARCH USE ONLY

Intended use

This immunoassay kit allows for the in vitro quantitative determination of  tumor associated glycoprotein 242 (CA242) in serum, plasma and other biological fluids.

Introduction

The tumor marker CA242 is defined by the monoclonal antibody C242. The chemical structure of the antigenic determinant is not exactly known, but the determinant have been shown to be a sialylated carbohydrate structure. In serum, CA242 is found on the same mucin-complex as CA50 and sialylated Lewisa (CA19-9). Thus, CA242 is related, but not identical to the epitope of CA19-9. Serum levels of CA242 are low in healthy subjects and subjects with benign diseases, while elevated levels are commonly found in serum from patients with gastro-intestinal cancer. The CA242 marker may be used as an aid in the diagnosis and management of patients with known or suspected gastro-intestinal carcinomas. The LINC-BIO CA242 EIA should not be used as a substitute for any established clinical examination of malignancy, but may be used as a complement to existing clinical and laboratory methods.

Test principle

The LINC-BIO CA 242 ELISA is a solid-phase, non-competitive immunoassay based on the direct sandwich technique. Calibrator, controls and patient samples are incubated together with anti-CA242 monoclonal antibody coated micro titer strips. CA242 present in calibrators, controls or samples is absorbed to the microtiter wells during the incubation. The strips are then washed and incubated with horseradish peroxidase (HPR) labeled anti-CA242 McAb. After washing ,    a TMB (3,35, 5 tetramethyl-benzidine) substrate solution is added to each well and the enzyme reaction is allowed to proceed. During the enzyme reaction a blue colour will develop if antigen is present. The intensity of the colour is proportional to the amount of CA242 antigen present in the samples.

The enzyme-substrate reaction is terminated by the addition of a sulphuric acid solution and the color change is measured spectrophotometrically at a wavelength of 450 nm ± 2 nm. Calibration curves are constructed for each assay by plotting absorbance value versus the concentration for each calibrator. The concentration of CA242 in the samples is then determined by comparing the O.D. of the samples to the calibration curve.

Materials and components

Reagent                                          Quantity

Assay plate                                           1

Calibrators                                           5 x 500ul

       With concentrations of 0 U/ml，5 U/ml，20 U/ml，100U/ml，200 U/ml,  400U/ml。

Controls                                             2 x 500ul

       With concentrations of 15-25 U/ml and 160-240 U/ml。

CA242-HRP conjugate                                                          1 x 10ml

Wash Buffer                                              1 x 30ml

(20 x concentrate)

Substrate Solution                                                                     1 x 10ml

Stop Solution                                                                            1 x 5ml

Sample collection and storage

Serum - Use a serum separator tube (SST) and allow samples to clot for 30 minutes before

centrifugation for 15 minutes at approximately 1000 x g. Remove serum and assay immediately or aliquot and store samples at -20° C or -80° C.

Plasma - Collect plasma using EDTA or heparin as an anticoagulant. Centrifuge samples for

15 minutes at 1000 x g at 2 - 8° C within 30 minutes of collection. Store samples at -20° C or -80° C. Avoid repeated freeze-thaw cycles.

Other biological fluids - Remove particulates by centrifugation and assay immediately or aliquot and store samples at -20° C or -80° C. Avoid repeated freeze-thaw cycles.

Note: Serum, plasma, and cell culture supernatant samples to be used within 7 days may be stored at 2-8 ° C, otherwise samples must stored at -20° C (≤ 3 months) or -80° C (≤ 6 months) to avoid loss of bioactivity and contamination. Avoid freeze-thaw cycles. When performing the assay slowly bring samples to room temperature.

It is recommended that all samples be assayed in duplicate.

DO NOT USE HEAT-TREATED SPECIMENS.

Limitations of the procedure

FOR RESEARCH USE ONLY. NOT FOR USE IN DIAGNOSTIC PROCEDURES.

1.         The kit should not be used beyond the expiration date on the kit label.

2.         Do not mix or substitute reagents with those from other lots or sources.

3.         If samples generate values higher than the highest standard, further dilute the samples with the Assay Diluent and repeat the assay. Any variation in standard diluent, operator, pipetting technique, washing technique,incubation time or temperature, and kit age can cause variation in binding.

4.         This assay is designed to eliminate interference by soluble receptors, ligands, binding proteins, and other factors present in biological samples. Until all factors have been tested in the Quantikine Immunoassay, the possibility of interference cannot be excluded.

Assay procedure

Allow all reagents to reach room temperature. All the reagents should be mixed thoroughly by gently swirling before pipetting. Avoid foaming. Arrange and label required number of strips. Prepare all reagents, working standards and samples as directed in the previous sections.

1.         Add 40 uL of Calibrators, Blank, or Sample per well. Cover with the adhesive strip. Incubate for 1 hours at 37° C.

2.         Aspirate the liquid of each well and wash. repeating the process five times.

Wash by filling each well with Wash Buffer (350 uL) using a squirt bottle, multi-channel pipette, manifold dispenser or autowasher. Complete removal of liquid at each step is essential to good performance. After the last wash, remove any remaining Wash Buffer by aspirating or decanting. Invert the plate and blot it against clean paper towels.

3.         Add 100 uL of HRP conjugate solution to each well. Incubate for 45 mins at 37°C.

4.         Aspirate each well and wash, repeating the process five times for a total of three washes. Refer to step2.

5.         Add 100 uL of Substrate Solution to each well. Incubate for 5 minutes at 37°C. Protect from light.

6.         Add 50 uL of Stop Solution to each well. If color change does not appear uniform, gently tap the plate to ensure thorough mixing.

7.         Determine the optical density at of each well within 15 minutes, using a microplate reader set to 405 nm.

Specificity
This assay recognizes recombinant and natural human CA242. No significant cross-reactivity or interference was observed.

Sensitivity

The minimum detectable dose of human CA242 is typically less than 1U/ml.

The sensitivity of this assay, or Lower Limit of Detection (LLD) was defined as the lowest protein concentration that could be differentiated from zero.

Detection Range

5-400 U/ml..

Important Note:

1.       The wash procedure is critical. Insufficient washing will result in poor precision and falsely elevated absorbance readings.

2.       It is recommended that no more than 32 wells be used for each assay run if manual pipetting is used since pipetting of all standards, specimens and controls should be completed within 5 minutes. A full plate of 96 wells may be used if automated pipetting is available.

3.       Duplication of all standards and specimens, although not required, is recommended.

4.       When mixing or reconstituting protein solutions, always avoid foaming.

5.       To avoid cross-contamination, change pipette tips between additions of each standard level, between sample additions, and between reagent additions. Also, use separate reservoirs for each reagent.

6.       To ensure accurate results, proper adhesion of plate sealers during incubation steps is necessary.

7.       Do not substitute reagents from one kit lot to another. Standard,  conjugate  a microtiter plates are matched for optimal performance.  Use only the reagents supplied by manufacturer.

Calculation of results

Average the duplicate readings for each calibrator, control, and sample and subtract the average zero standard optical density. Create a calibration curve by reducing the data using computer software capable of generating a four parameter logistic (4-PL) curve-fit or liner curve. As an alternative, construct a calibration curve by plotting the mean absorbance for calibrator on the y-axis against

the concentration on the x-axis and draw a best fit curve through the points on the graph. The data may be linearized by plotting the log of the CA242 concentrations versus the log of the O.D. and the best fit line can be determined by regression analysis. This procedure will produce an adequate but less precise fit of the data. If samples have been diluted, the concentration read from the standard curve must be multiplied by the dilution factor.

Storage of test kits and instrumentation

1.       Unopened test kits should be stored at 2-8°C upon receipt and the microtiter plate should be kept in a sealed bag with desiccants to minimize exposure to damp air. The test kit may be used throughout the expiration date of the kit (six months from the date of manufacture). Refer to the package label for the expiration date.

2.       Opened test kits will remain stable until the expiring date shown, provided it is stored as prescribed above. 

3.       Do not remove microtiter plate from the storage bag until needed.  Unused strips should be stored at 2-8°C in their pouch with the desiccant provided.

4.       A microtiter plate reader with a bandwidth of 10nm or less and an optical density range of 0-3 OD or greater at 450nm wavelength is acceptable for use in absorbance measurement.

5.       Use fresh disposable pipette tips for each transfer to avoid contamination.

6.       Substrate Solution is easily contaminated.  If bluish prior to use, do not use.

Precaution

The Stop Solution suggested for use with this kit is an acid solution. Wear eye, hand, face, and clothing protection when using this material.