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We Provide Quality Immunoassay Kits

Detect Small And Large Analytes Accurately & Efficiently

Enzo Life Sciences offers hundreds of ELISA kits in both immunometric and competitive assay formats. As scientists and manufacturers of kits, we understand the critical nature of your research.
Each enzyme-linked immunosorbent assay is put through rigorous testing to ensure high precision, accuracy, sensitivity, and specificity. You can be confident that you will obtain reproducible results, day-after day and lot-after-lot.

What is an ELISA Kit?

Enzyme-linked immunosorbent assay (ELISA) is an analytical, plate-based technique to detect and quantify the presence of an target analyte in a liquid sample using antibodies.


Why use our ELISA?


Our ELISA Kits are validated in multiple sample matrices from serum and saliva to urine and feces

Enzo ELISA assays features low reactivity with structurally related molecules

better quantification thresholds measure low endogenous levels with ease

Our ELISA are adaptable to automated equipment for higher throughput systems

Entrust your precious samples, time, and research budget to ELISA assay kits from Enzo Life Sciences

Assay kits can be convenient time-saving tools to help accelerate your research, but not all assays are created equal. Some that promise convenience fail to deliver biologically relevant sensitivity, or the reproducibility needed for long-term studies. This can cost you more time and money in the end. Whether you use an ELISA assay for biomarker detection, assess cellular function with fluorescent probes, or screen enzyme modulators with activity assays, every Enzo assay kit includes something a lot of other companies out there today can’t -- Experience.

It takes more than just an antibody pair to make an ELISA assay. Building an immunoassay requires screening multiple antibodies, selection of appropriate standards and conjugates, establishing proper sample prep protocols, and validation of the assay in relevant matrices. Our expertise in developing ELISAs is further backed by two decades of manufacturing excellence. Strict validation criteria and state-of-the-art manufacturing facilities deliver reproducible assays that continue to be cited in peer-reviewed publications by scientists around the world.

Reliable Manufacturing Ensures Consistent Results

cyclic AMP ELISA Assay standard curves

The graph above demonstrates the robust nature of our immunoassays, showing standard curves for 7 lots of our competitive ELISA for cyclic AMP manufactured over 3 years.

"For decades, Enzo’s ELISAs have been trusted by researchers. We have long been a manufacturer of consistent, reliable, functional immunoassays that deliver relevant results at a cost-effective price per sample. Maria Pulina
Product Manager
Highly Cited. Highly Trusted.

Enzo’s ELISA Kits have been cited more than 1800 times!
You can find the citations on each product page.

Download our Lists of Cited Samples

Product Flyers
Hormone ELISA - Cited Samples
Product Flyers
Wildlife Endocrinology - Cited Sample Types

The Basics of ELISA Immunoassays

Understanding the basic principles of immunoassays is easy. The essential components of antibody-based immunoassay systems are threefold: an antigen to detect and perhaps quantitate; a specific antibody to this antigen; and a system to measure the amount of antigen in a given sample. Although it appears to be a very simple system, in many cases a number of other assay materials are necessary to allow for quick and convenient measurement.

Immunometric / Sandwich ELISA Kit

Sandwich ELISA protocol overview

Immunometric assays, also known as sandwich ELISAs (enzyme-linked immunosorbent assay), use two antibodies specific to the antigen to capture or "sandwich” antigen in the well for detection. Immunometric assays exhibit a direct correlation between antigen concentration and substrate response. Immunometric assays typically employ a "capture” antibody coated on the plate to bind the antigen of interest. During a second incubation, the antigen is bound by a second "detection” antibody that is also specific to the antigen. The detection antibody can either be bound by a secondary antibody-enzyme conjugate, or the detection antibody itself is enzyme-conjugated. When chromogenic substrate is added to the assay to develop color, samples with high antigen concentration generate more signal than those with low antigen concentration, producing a signal directly proportional to the amount of antigen in the sample. This correlation can then be used to extrapolate the concentration of antigen in an unknown sample from a standard curve.

Sandwich ELISA Protocol
  1. Sample is added to well coated with capture antibody and incubated
  2. Wells are washed to remove unbound molecules
  3. Add detection antibody and incubate to bind to antigen creating a “sandwich”
  4. Wash away excess detection antibody
  5. Add secondary antibody-enzyme conjugate and wash. Conjugated enzyme is typically horseradish peroxidase (HRP) or alkaline phosphatase (AP)
    Note: This step may be omitted if the reporting enzyme is directly conjugated to the detection antibody
  6. Add substrate and incubate to develop signal
  7. Measure signal in plate reader

Competitive ELISA kit

Competitive ELISA protocol

In competitive enzyme immunoassays (EIA) the antigen in a sample competes for limited antibody binding sites with antigen conjugated to a reporter enzyme. This produces an inverse relationship between antigen concentration and substrate turnover. Competitive EIAs typically use a single antibody to a small molecular weight antigen, generally less than 10,000 Daltons. During incubation, samples with high antigen content result in unlabeled antigen being bound in greater amounts than conjugated antigen. When chromogenic substrate is added to the assay to develop color, samples with high antigen concentration generate a lower signal than those containing low antigen concentration, yielding the inverse correlation between antigen concentration in the sample and color development in the assay. This relationship can then be used to extrapolate antigen concentration in an unknown sample from a standard curve. This type of reaction is one of the few methods possible for small molecular weight antigens, such as steroids, drugs, lipids and peptides.

Competitive ELISA Protocol
  1. Sample is added to well coated with anti-species antibody
  2. Enzyme-conjugated antigen added to well with sample
  3. Capture antibody added to well and incubated. The antigen in the sample and the enzyme-conjugated antigen compete for binding to the capture antibody. The anti-species antibody coated in the well binds the capture antibody.
  4. Well is washed to remove excess antibody and enzyme-conjugated antigen
  5. Add substrate to develop signal
  6. Measure signal in plate reader

Do you want to know more about ELISA?

Download our Immunoassay E-book

Enzo offers research kits, biochemicals and biologicals backed by over 40 years of expertise. As Scientists Enabling Scientists™, we realize the value in providing relevant information to our customers working in the fields of life sciences, drug development and clinical research. We are happy to provide simple but useful tips for improving daily tasks as well as the overall quality of your research.
With this in mind, here is an e-book that answers important questions such as:

  • What are the Differences Between ELISA Assay Types?
  • 10 Tips for Successful ELISA Assays
  • In-depth Insights on ELISA:
    • %CV in ELISA: How to reduce them and why they’re important
    • Dilutional linearity, parallelism, spike-and-recovery in ELISA: How to QC your results?
    • How to validate sample dilutions and achieve linearity in new sample types

Immunoassay ebook cover

250 Validated ELISA Kits for All Your Research Needs

Featured Literature

Immunoassay Kits

Stay up to date with our latest innovations


Bioprocess ELISA Kits
Sensitive ELISA Assays for measuring PEGylated Proteins and detecting residual Protein A contaminant.

Cyclic Nucleotides ELISA Kits
The most sensitive colorimetric ELISA Assays for detection of cAMP and cGMP, key second messenger signaling molecules.

Inflammation ELISAs
Over 100 sensitive ELISAs for immunology & inflammation research.

Heat Shock Response ELISA Kits
The definitive collection of Stressgen® ELISA Assays for heat shock.

Oxidative Stress ELISA Kits
Detect & Quantify Biomarkers of Oxidative Stress

Toxicology ELISA Kits
Biomarker assays for assessment of response to toxic compounds.

Steroid / Hormone ELISA kits
Sensitive ELISAs for the detection of steroid and hormones.

Wnt Pathway ELISA Kits
Assays for critical Wnt signaling components GSK-3beta, Dkk-1, and β-catenin.

Your Partner in ELISA Services

We test, so you can discover.

Assay Validation | Western Blot Services | ELISA Services

Absorbance 96 Plate Reader Plate Readers Just Got Personal

  • Perfect for ELISA Kits
  • Endpoint and kinetic assays
  • Quantitative and qualitative evaluation
  • Custom protocols and reports

Oxytocin ELISA kit

The most sensitive, specific and flexible alternative to more costly and time-consuming methods for oxytocin detection.

Oxytocin is a neurohypophysial peptide which is produced in the paraventricular nuclei of the hypothalamus and stored in the posterior pituitary. A hormone once thought to be limited to female smooth muscle reproductive physiology, more current findings have determined that oxytocin also functions as a neurotransmitter, may be involved in neuropsychiatric disorders, social/sexual behavior and is important in male reproductive physiology. Oxytocin and the related neurohypophysial peptide, Arg8-Vasopressin, maintain renal water and sodium balance.

  • Sensitive quantification of 15pg/mL oxytocin
  • Negligible reactivity with vasopressin provides confidence in assay results
  • Faster and less costly than LC/MS
  • Widely published in peer reviewed literature
ELISA Standard Curve

Featured Application

Wildlife Endocrinology -
Enzo’s trusted steroid hormone ELISA kits deliver sensitivity and reproducibility

With thousands of species each year listed as endangered or threatened, the work done by biologists around the world to understand and preserve animal health is never ending.
Reproduction studies and stress are two of the most common concerns today. Hormone analysis continues to be widely accepted for monitoring stress response and evaluating reproductive health on wildlife.
Enzo Life Sciences provides a broad range of immunoassay kits for monitoring stress, reproductive physiology, health and welfare, and survival of wildlife animals.

Featured ELISA Assays
Stress Monitoring: Corticosterone ELISA Kit
Reproductive Studies: Testosterone ELISA Kit

Quantify difficult-to-detect analytes

Reliable detection of analytes that are present at low concentrations is a critical need for early diagnosis and treatment of various diseases. Enzo Life Sciences has developed a highly sensitive ELISA Amplification System to be used with your most difficult-to-detect markers.

  • Increase sensitivity up to 50-fold over traditional ELISA kits
  • Minimal additional time needed to complete amplification step
  • Flexible format for use with any immunometric, sandwich ELISAs where greater sensitivity is desired
  • Convenient one or five 96-well plate sizes for high throughput analysis
  • Easy-to-use, simple procedure with nominal ELISA protocol modification
ELISAs based on Amp’d Technology

ELISA Experts Corner

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