Immunoassay Kits

Kits

Our range spans ELISA, CLIA and antibody pair kits for quantifying proteins, peptides and hormones in serum, plasma, cell lysate and tissue homogenate. Each format trades off sensitivity, dynamic range and assay time differently, so use the comparisons below to match a format and product to your sample type and target.

Mouse IL-6 ELISA Kit Mouse IL-6 Sandwich ELISA Kit from the St John's Laboratory catalogue
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Kits by Format

Antibody pairs are carefully selected for optimal performance in sandwich immunoassays, including ELISA and lateral flow, with each pair including matched capture and detection antibodies validated for target specificity and sensitivity. ELISA kits are designed for precise quantification of proteins, cytokines and biomarkers, and include pre-coated plates and ready-to-use reagents for accuracy, reproducibility and ease of use across multiple sample types.

Kit Selection

Choosing a Kit

Compare sensitivity, dynamic range, sample volume, assay time and matrix compatibility across the three formats to find the right fit for your target and sample type.

FormatSensitivity (LOD)Dynamic rangeSample volumeAssay timeMatrix compatibility
ELISA (sandwich)Low pg/mL~2–3 logs50–100 µL3–5 hSerum, plasma, CSF, supernatant
CLIASub-pg/mL~3–4 logs20–50 µL2–3 hAs above, higher sensitivity
Antibody pairsFormat-dependentCustomCustomCustomBuild your own assay
Quality Control

Validation & QC

Each kit's Certificate of Analysis (COA) reports key performance metrics to confirm accuracy, precision and matrix compatibility. Use these values to set acceptance criteria, compare kits, and check for reproducible results across plates, operators and instruments. Click a metric for what it means and why it matters.

Spike & recovery 80–120%

Measures how accurately the assay recovers a known amount of analyte added to your sample matrix. Values outside this range point to matrix interference affecting accuracy.

Linearity of dilution R² ≥ 0.98

Confirms the assay reads proportionally as a sample is serially diluted (parallelism). Poor linearity means results are unreliable at some dilutions.

Intra/inter-assay CV ≤10% / ≤15%

Coefficient of variation within a single plate (intra) and across separate runs (inter). Lower CVs mean more reproducible results between replicates, operators and plates.

LOD / LOQ Kit-specific

The Limit of Detection and Limit of Quantification set the lowest concentration the kit can reliably detect and accurately measure. Check this against your expected sample concentration before ordering.

Format Comparison

ELISA vs CLIA

ELISA and CLIA measure the same analytes but differ in detection chemistry, sensitivity and instrumentation. Use ELISA for routine quantification on a standard plate reader; choose CLIA when you need higher sensitivity, a wider dynamic range or a shorter assay time on a luminometer. Toggle a format to highlight its column.

FeatureELISACLIA
SensitivityLow pg/mLSub-pg/mL
ReadoutColorimetric (450 nm)Chemiluminescent
ThroughputHigh (plate readers)High (luminometers)
Total time3–5 h2–3 h
Support

FAQs

What should I check if my standard curve is non-linear? +

Re-prepare the standards, confirm the reader settings, keep incubations uniform and check wash stringency.

High background with serum samples? +

Increase blocking, dilute samples further, and use matrix-matched standards.

Can I run CLIA on an ELISA reader? +

No, CLIA needs a luminometer. Use ELISA if you only have an absorbance plate reader.

Need Help Picking a Kit?

Tell us your targets, sample matrix, species, instrument and throughput. We'll recommend kits and share QC details.

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For Research Use Only. All products are intended for in vitro research purposes and are not for use in diagnostic procedures.

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