FOR RESEARCH USE ONLY.  

NOT FOR USE IN DIAGNOSTIC PROCEDURES.  

Rat Interleukin 18 (IL-18) ELISA Kit instruction

Intended use

This IL-18 ELISA kit is intended Laboratory for Research use only and is not for use in diagnostic or therapeutic procedures. The Stop Solution changes the color from blue to yellow and the intensity of the color is measured at 450 nm using a spectrophotometer. In order to measure the concentration of IL-18 in the sample, this IL-18 ELISA Kit includes a set of calibration standards. The calibration standards are assayed at the same time as the samples and allow the operator to produce a standard curve of Optical Density versus IL-18 concentration. The concentration of IL-18 in the samples is then determined by comparing the O.D. of

the samples to the standard curve.

Sample collection and storages

Serum - Use a serum separator tube and allow samples to clot for 30 minutes before centrifugation for 10 minutes at approximay 3000×g. Remove serum and assay immediay or aliquot and store samples at -20℃ or -80℃.Avoid repeated freeze-thaw cycles

Plasma - Collect plasma using EDTA or heparin as an anticoagulant. Centrifuge samples for 30 minutes at 3000×g at 2-8℃ within 30 minutes of collection. Store samples at -20℃or -80℃. Avoid repeated freeze-thaw cycles.

Cell culture supernates and other biological fluids - Remove particulates

by centrifugation and assay immediay or aliquot and store samples at -20℃or -80℃. Avoid repeated freeze-thaw cycles.

Note:  The samples shoule be centrifugated dequay and no hemolysis or granule was allowed.

Materials required but not supplied 

1.  Standard microplate reader(450nm)

2.  Precision pipettes and Disposable pipette tips.

3.  37 ℃ incubator

Precautions

1.  Do not substitute reagents from one kit to another. Standard, conjugate and microplates are matched for optimal performance. Use only the reagents supplied by

manufacturer.

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

3.  Mix all reagents before using.

Remove all kit reagents from refrigerator and allow them to reach room temperature

( 20-25° C)

Materials supplied

Name                  96 determinations    48 determinations

Microelisa stripplate       12*8strips             12*4strips

Standard                   0.3ml               0.3ml

Sample diluent              6.0ml               3.0ml

HRP-Conjugate reagent       10.0ml               5.0ml

20X Wash solution            25ml                15ml

Chromogen Solution A        6.0ml                3.0ml

Chromogen Solution B        6.0ml                3.0ml

Stop Solution                6.0ml                3.0ml

Closure plate membrane        2                    2

User manual                  1                    1

Sealed bags                   1                    1

Note: Standard concentration was followed by:  

160、80、40、20、10、5  pg/mL.

Reagent preparation 

20×wash solution:Dilute with Distilled or deionized water 1:20.

Assay procedure

1.  Prepare all reagents before starting assay procedure. It is recommended that all Standards and Samples be added in duplicate to the Microelisa Stripplate.

2.  Add standard: Set Standard wells, testing sample wells. Add standard 50μl to standard well.

3.  Add Sample: Add testing sample 10μl Then add sample diluent 40μl to testing sample well; Blank well doesn’t add anyting.

4.  Add 100μl of HRP-conjugate reagent to each well, cover with an adhesive strip and incubate for 60 minutes at 37° C.  

5.  Aspirate each well and wash, repeating the process four times for a total of five washes. Wash by filling each well with Wash Solution (400μl) using a squirt bottle, manifold dispenser or autowasher. Complete removal of liquid at each step is essential to good performance. After the last wash, remove any remaining Wash Solution by aspirating or decanting. Invert the plate and blot it against clean paper towels.

6.  Add chromogen solution A 50μl and chromogen solution B 50μl to each well. Gently mix and incubate for 15 minutes at 37°C . Protect from light.

7.  Add 50μl Stop Solution to each well. The color in the wells should change from blue to yellow. If the color in the wells is green or the color change does not appear uniform, gently tap the plate to ensure thorough mixing.      

8.  Read the Optical Density (O.D.) at 450 nm using a microtiter plate reader

within 15 minutes.

Calculation of results

1. This standard curve is used to determine the amount in an unknown sample. The standard curve is generated by plotting the average O.D. (450 nm) obtained for eachof the six standard concentrations on the vertical (Y) axis versus the corresponding concentration on the horizontal (X) axis.  

2. First, calculate the mean O.D. value for each standard and sample. All O.D. values, are subtracted by the mean value of the zero standard before result interpretation. Construct the standard curve using graph paper or statistical software.  

3. To determine the amount in each sample, first locate the O.D. value on the Y-axis and extend a horizontal line to the standard curve. At the point of intersection, draw a vertical line to the X-axis and read the corresponding concentration.  

4. Any variation in operator, pipetting and washing technique, incubation time or temperature, and kit age can cause variation in result. Each user should obtain their own standard curve.

5. The sensitivity by this assay is 1.0  pg/mL.

6. Standard curve   

Storage：  2-8℃.

validity： six months.  

FOR RESEARCH USE ONLY; NOT FOR THERAPEUTIC OR DIAGNOSTIC APPLICATIONS!

PLEASE READ THROUGH ENTIRE PROCEDURE BEFORE BEGINNING!