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Human IDO(Indoleamine-2,3-Dioxygenase) ELISA Kit

  • Cat.No.:E-EL-H2162

  • Reactivity: Human

To Purchase E-EL-H2162

  • 96T
  • 48T
  • 24T
  • 96T*5
  • 96T*10
Price: $609

Product Details


Assay type Sandwich-ELISA
Format 96T/48T
Assay time 3.5h
Detection range 0.31-20 ng/mL
Sensitivity 0.19 ng/mL
Sample type &Sample volume serum, plasma and other biological fluids; 100μL
Specificity This kit recognizes Human IDO in samples. No significant cross-reactivity or interference between Human IDO and analogues was observed.
Reproducibility Both intra-CV and inter-CV are < 10%.
Application This ELISA kit applies to the in vitro quantitative determination of Human IDO concentrations in serum, plasma and other biological fluids.

Test Principle

This ELISA kit uses the Sandwich-ELISA principle. The micro ELISA plate provided in this kit has been pre-coated with an antibody specific to Human IDO. Standards or samples are added to the micro ELISA plate wells and combined with the specific antibody. Then a biotinylated detection antibody specific for Human IDO and Avidin-Horseradish Peroxidase (HRP) conjugate are added successively to each micro plate well and incubated. Free components are washed away. The substrate solution is added to each well. Only those wells that contain Human IDO, biotinylated detection antibody and Avidin-HRP conjugate will appear blue in color. The enzyme-substrate reaction is terminated by the addition of stop solution and the color turns yellow. The optical density (OD) is measured spectrophotometrically at a wavelength of 450 nm ± 2 nm. The OD value is proportional to the concentration of Human IDO. You can calculate the concentration of Human IDO in the samples by comparing the OD of the samples to the standard curve.

Kit components & Storage

An unopened kit can be stored at 2-8℃ for 1 month. If the kit is not supposed to be used within 1 month, store the components separately according to the following conditions once the kit is received.
Micro ELISA Plate(Dismountable) 96T: 8 wells ×12 strips
48T: 8 wells ×6 strips
-20℃, 6 months
Reference Standard 96T: 2 vials
48T: 1 vial
Concentrated Biotinylated Detection Ab (100×) 96T: 1 vial, 120 μL
48T: 1 vial, 60 μL
Concentrated HRP Conjugate (100×) 96T: 1 vial, 120 μL
48T: 1 vial, 60 μL
-20℃(Protect from light), 6 months
Reference Standard & Sample Diluent 1 vial, 20 mL 2-8°C, 6 months
Biotinylated Detection Ab Diluent 1 vial, 14 mL
HRP Conjugate Diluent 1 vial, 14 mL
Concentrated Wash Buffer (25×) 1 vial, 30 mL
Substrate Reagent 1 vial, 10 mL 2-8℃(Protect from light)
Stop Solution 1 vial, 10 mL 2-8°C
Plate Sealer 5 pieces
Manual 1 copy
Certificate of Analysis 1 copy

Technical Data


Intra-assay Precision (Precision within an assay): 3 samples with low, mid range and high level Human IDO were tested 20 times on one plate, respectively.
Inter-assay Precision (Precision between assays): 3 samples with low, mid range and high level Human IDO were tested on 3 different plates, 20 replicates in each plate.

  Intra-assay Precision Inter-assay Precision
Sample 1 2 3 1 2 3
n 20 20 20 20 20 20
Mean (ng/mL) 0.95 1.81 7.37 1.03 1.96 7.88
Standard deviation 0.06 0.10 0.23 0.07 0.12 0.41
CV (%) 6.32 5.52 3.12 6.80 6.12 5.20


The recovery of Human IDO spiked at three different levels in samples throughout the range of the assay was evaluated in various matrices.

Sample Type Range (%) Average Recovery (%)
Serum(n=8) 90-101 95
EDTA plasma (n=8) 86-100 92
Cell culture media (n=8) 92-108 98


Samples were spiked with high concentrations of Human IDO and diluted with Reference Standard & Sample Diluent to produce samples with values within the range of the assay.

Target Information

Database LinksSwissProt:   P14902
SynonymsIDO-1, INDO
Research AreaCancer, Cardiovascular, Metabolism, Signal transduction

Assay Procedures

elisa assay procedure 1

1. Add 100μL standard or sample to the wells. Incubate for 90 min at 37°C

elisa assay procedure 2

2. Discard the liquid, immediately add 100μL Biotinylated Detection Ab working solution to each well. Incubate for 60 min at 37°C

elisa assay procedure 3

3. Aspirate and wash the plate for 3 times

elisa assay procedure 4

4. Add 100μL HRP conjugate working solution. Incubate for 30 min at 37°C. Aspirate and wash the plate for 5 times

elisa assay procedure 5

5. Add 90μL Substrate Reagent. Incubate for 15 min at 37°C

elisa assay procedure 6

6. Add 50μL Stop Solution

elisa assay procedure 7

7. Read the plate at 450nm immediately. Calculation of the results


  1. npj Regenerative Medicine (2022) IF: 14.404
    Enforced mesenchymal stem cell tissue colonization counteracts immunopathology

    DOI: 10.1038/s41536-022-00258-z

    PMID: 36261464

    Sample: MSCs
    Design, synthesis and biological evaluation of a novel library of antimitotic C2-aroyl/arylimino tryptamine derivatives that are also potent inhibitors of indoleamine-2, 3-dioxygenase (IDO)

    DOI: 10.1016/j.ejps.2018.08.033

    Sample: MCF7 Cells,A549 cells
  3. Scientific Reports (2020) IF: 3.998
    Proteinuria is Associated with Urinary Loss of Cubilin and Vitamin D-Binding Protein in Patients with Preeclampsia

    DOI: 10.1038/s41598-020-60924-4

    PMID: 32127613

    Sample: Plasma,Urine
  4. BMC Pharmacology & Toxicology (2020) IF: 2.483
    1-MT inhibits the invasion of CBP-resistant ovarian cancer cells via down-regulating IDO expression and re-activating immune cells function

    DOI: 10.1186/s40360-020-00439-w

    PMID: 32912307

    Sample: SKOV3 cell
  5. Egyptian Journal of Bronchology (2023)
    Activities of plasma indoleamine-2, 3-dioxygenase (IDO) enzyme in Nigerian patients with lung diseases: basis for tryptophan supplementation or IDO inhibitor use

    DOI: 10.1186/s43168-022-00174-2

    Sample: plasma
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