Human IL18 Assay Kit

Also called IGIF (interferon gamma inducing factor), IL18 is a pro-inflammatory cytokine secreted mainly by macrophages. Its biological activity is close to that of IL12, and it can enhance NK cell activity as well as induce IFNg secretion by PBMC.
An important role of IL18 is in eliminating VEGF from the eye, thus protecting the retina. It is used together with anti-VEGF antibodies in the treatment of AMD (age-related macular degeneration).
As well as this physiological role, IL18 dysregulation leads to severe inflammatory reactions.
Cisbio's Human IL18 kit is a homogeneous, add and read assay to measure IL18 secretion in supernatant. It offers a fast, efficient alternative to ELISA.

Sample size 16 µL
Final assay volume 20 µL
Kit components Lyophilized standard, frozen detection antibodies, buffers & protocol.
LOD & LOQ (in Diluent) 18 pg/mL & 43 pg/mL
Range 43 – 8,000 pg/mL
Time to result 1h at RT
Calibration NIBSC (03/200) value (IU/mL) = 5 x HTRF hIL18 value (pg/mL)
Species Human only
Download Insider tips for PBMC isolation Technical Note
Download cytokine release from fresh blood samples application notes

Assay principle

The assay protocol, using a Cisbio 96-well low volume or a 384-well small volume white plate (20 µL final), is described below. Cell supernatant, sample or standard are dispensed directly into the assay plate for the detection by HTRF® reagents. The antibodies labeled with the HTRF donor and acceptor are pre-mixed and added in a single dispensing step, to further streamline the assay procedure. The assay can be run in 96 to 1536-well plates by simply resizing each addition volume proportionally.

The 4 Parameter Logistic (4PL) curve is commonly recommended for fitting an ELISA standard curve. This regression enables the accurate measurement of an unknown sample across a wider range of concentrations than linear analysis, making it ideally suited to the analysis of biological systems like cytokine releases.


Cytokines assay principle add


Cytokines assay principle read

(1) Assay data analysis:

  • "Guidelines for data reduction" button will show you how dealing with HTRF data processing and 4PL 1/y2 fitting.
  • "MyAssays" button will direct you to a free online software able to run hIL18 analysis.


How to use HTRF cytokine assays

How to measure multiple cytokines from 1 sample

Analytical performance


Intra-assay (n=24)

Sample Mean [IL18] (pg/mL) CV
1 100 10%
2 4500 3%
3 6800 4%
  Mean CV 6%

Each of the 3 samples was measured 24 times, and % CV was calculated for each sample.

Inter-assay (n=4)

Sample [IL18] (pg/mL) Mean (delta R) CV
1 155 410 3%
2 751 1855 5%
3 3636 6570 5%
    Mean CV 4%

Each of the samples was measured in 4 different experiments, and % CV was calculated for each sample.

Part#, inserts & MSDS

Ordering Info

DescriptionCat. noProduct insertMSDS
Human IL18 kit - 500 tests62HIL18PEG
Human IL18 kit - 10,000 tests62HIL18PEH

Companion products

DescriptionCat. noProduct insertMSDS
Human IL18 kit - 3 Standards62HIL18CD3
Human IL18 kit - Standard62HIL18CDA