ELISA Kit for Interleukin 31 (IL31)


This assay has high sensitivity and excellent specificity for detection of Interleukin 31 (IL31).
No significant cross-reactivity or interference between Interleukin 31 (IL31) and analogues was observed.


Matrices listed below were spiked with certain level of recombinant Interleukin 31 (IL31) and the recovery rates were calculated by comparing the measured value to the expected amount of Interleukin 31 (IL31) in samples.

Matrix Recovery range (%) Average(%)
serum(n=5) 90-99 94
EDTA plasma(n=5) 85-96 93
heparin plasma(n=5) 81-99 87


Intra-assay Precision (Precision within an assay): 3 samples with low, middle and high level Interleukin 31 (IL31) were tested 20 times on one plate, respectively.
Inter-assay Precision (Precision between assays): 3 samples with low, middle and high level Interleukin 31 (IL31) were tested on 3 different plates, 8 replicates in each plate.
CV(%) = SD/meanX100
Intra-Assay: CV<10%
Inter-Assay: CV<12%


The linearity of the kit was assayed by testing samples spiked with appropriate concentration of Interleukin 31 (IL31) and their serial dilutions. The results were demonstrated by the percentage of calculated concentration to the expected.

Sample 1:2 1:4 1:8 1:16
serum(n=5) 90-104% 98-105% 94-101% 98-105%
EDTA plasma(n=5) 90-101% 78-99% 81-97% 89-98%
heparin plasma(n=5) 81-104% 96-105% 80-93% 91-99%


The stability of kit is determined by the loss rate of activity. The loss rate of this kit is less than 5% within the expiration date under appropriate storage condition.
To minimize extra influence on the performance, operation procedures and lab conditions, especially room temperature, air humidity, incubator temperature should be strictly controlled. It is also strongly suggested that the whole assay is performed by the same operator from the beginning to the end.

Reagents and materials provided

Reagents Quantity Reagents Quantity
Pre-coated, ready to use 96-well strip plate 1 Plate sealer for 96 wells 4
Standard 2 Standard Diluent 1×20mL
Detection Reagent A 1×120µL Assay Diluent A 1×12mL
Detection Reagent B 1×120µL Assay Diluent B 1×12mL
TMB Substrate 1×9mL Stop Solution 1×6mL
Wash Buffer (30 × concentrate) 1×20mL Instruction manual 1

Assay procedure summary

1. Prepare all reagents, samples and standards;
2. Add 100µL standard or sample to each well. Incubate 1 hours at 37°C;
3. Aspirate and add 100µL prepared Detection Reagent A. Incubate 1 hour at 37°C;
4. Aspirate and wash 3 times;
5. Add 100µL prepared Detection Reagent B. Incubate 30 minutes at 37°C;
6. Aspirate and wash 5 times;
7. Add 90µL Substrate Solution. Incubate 10-20 minutes at 37°C;
8. Add 50µL Stop Solution. Read at 450nm immediately.



Magazine Citations
allergy and clinical immunology Increased serum levels of Interleukin-31 could modulate inflammatory processes in multiple sclerosis Siaic-Review:Source
BMC Immunol Increased levels of interleukin 31 (IL-31) in osteoporosis PubMed: 2644965
Sci Rep. Interleukin-31 expression and relation to disease severity in human asthma pmc:PMC4783779
Exp Dermatol. Immediate-type allergic and protease-mediated reactions are involved in scratching behaviour induced by topical application of Dermatophagoides farinae extract in NC/Nga mice. pubmed:28191683
Nat Commun.  The transcription factor EPAS1 links DOCK8 deficiency to atopic skin inflammation via IL-31 induction. pubmed:28067314
Experimental Dermatology Immediate-type allergic and protease-media ted reactions are involved in scratching behavior induced by topical application of Dermatophagoides farinae extract in NC/Nga mice doi:10.1111
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