Cortisol (Hydrocortisone) Monoclonal Antibody for Stress Response CLIA IVD Development
Cortisol (hydrocortisone) is the principal glucocorticoid hormone in humans, produced by the zona fasciculata of the adrenal cortex, with a molecular weight of 362 Da (molecular formula C₂₁H₃₀O₅). Cortisol secretion is tightly regulated by the hypothalamic-pituitary-adrenal (HPA) axis: hypothalamic CRH stimulates pituitary ACTH release, which drives adrenal cortisol production. Cortisol secretion follows a pronounced diurnal rhythm, with peak serum concentrations in the early morning (typically 5–25 μg/dL, 138–690 nmol/L) and nadir values at midnight. In serum, 80–90% of circulating cortisol is bound to corticosteroid-binding globulin (CBG, transcortin) and albumin; the biologically active free fraction constitutes approximately 10% of total serum cortisol. Salivary cortisol closely reflects free serum cortisol and is increasingly used as a non-invasive sampling matrix for HPA axis assessment.
Cortisol is a high-clinical-priority diagnostic biomarker across multiple endocrine conditions. Cushing's syndrome (endogenous hypercortisolism), characterised by chronically elevated cortisol (>22 μg/dL or 24-hour urinary free cortisol exceeding the upper limit of normal), presents with central obesity, hypertension, diabetes, osteoporosis, and psychological disturbance — with an annual incidence of 2–3 per million but significant diagnostic delay due to symptom overlap. Addison's disease (primary adrenal insufficiency) is defined by morning cortisol <3 μg/dL (<83 nmol/L) with elevated ACTH; adrenal crisis is a life-threatening emergency. The low-dose dexamethasone suppression test (LDDST) assesses HPA axis negative feedback: normal response is cortisol suppression to <1.8 μg/dL; non-suppression suggests Cushing's syndrome. Midnight salivary cortisol <145 ng/dL (<4 nmol/L) is recommended by Endocrine Society guidelines as a Cushing's screening test. Relative adrenal insufficiency (critical illness-related corticosteroid insufficiency, CIRCI) affects 10–20% of ICU patients and increases mortality; cortisol stimulation testing guides hydrocortisone supplementation.
For IVD immunoassay development, cortisol presents the same technical constraint as all small-molecule steroid hormones: at 362 Da, it is too small for sandwich format and requires competitive immunoassay. Sekbio provides a complete competitive CLIA development kit: S17-Cortisol-w901M antibody (mouse anti-hydrocortisone, IgG2a isotype, ≥90% purity, high affinity) combined with Cortisol-BSA Conjugate (for use as the coating antigen in competitive CLIA/ELISA wells or microparticle coating) and Cortisol-3-OVA Conjugate (alternative immunogen or coating antigen). This complete reagent set from a single ISO 13485-certified supplier simplifies competitive cortisol assay development for serum, plasma, salivary, and urinary sample matrices.
One anti-cortisol monoclonal antibody plus two cortisol conjugates for complete competitive CLIA immunoassay development.
| Catalog No. | Product Name | Type | Purity | Intended Use | Storage |
|---|---|---|---|---|---|
| S17-Cortisol-w901M | Mouse Anti-Hydrocortisone Monoclonal Antibody | mAb (IgG2a) | ≥90% SDS-PAGE | Capture Antibody — Competitive CLIA | −20°C long-term |
| Cortisol-BSA Conjugate | Cortisol-Bovine Serum Albumin Conjugate | Hapten-Protein Conjugate | — | Coating Antigen — Competitive CLIA/ELISA | −20°C long-term |
| Cortisol-3-OVA Conjugate | Cortisol-3-Ovalbumin Conjugate | Hapten-Protein Conjugate | — | Immunogen / Alternative Coating Antigen | −20°C long-term |
All products supplied in PBS pH 7.4. MOQ 1 mg per SKU. OEM quantities (10 mg–gram scale) available. Contact info@sekbio.com for bulk pricing and technical documentation.
A complete, pre-matched competitive CLIA reagent set engineered for Cushing's syndrome diagnosis, adrenal function assessment, and stress response monitoring.
S17-Cortisol-w901M is an IgG2a isotype mouse monoclonal antibody against hydrocortisone. The IgG2a isotype offers strong complement fixation and Fc receptor binding, characteristics associated with high-affinity antigen capture in competitive immunoassay formats. High antibody affinity for cortisol is critical for achieving the sensitivity required in salivary cortisol assays (<1 ng/mL LOD) and distinguishing Addison's disease levels (<3 μg/dL) from normal morning cortisol values (5–25 μg/dL) in serum-based CLIA platforms.
Sekbio supplies the complete competitive CLIA reagent set: antibody (S17-Cortisol-w901M) plus two cortisol conjugates — Cortisol-BSA (for competitive CLIA/ELISA coating antigen) and Cortisol-3-OVA (immunogen and alternative coating antigen). Sourcing antibody and coating antigen from a single ISO 13485-certified manufacturer ensures pre-characterised reagent compatibility, simplifying assay development timelines and reducing reagent matching validation burden for OEM kit developers.
All three cortisol reagents are specifically developed and characterised for competitive immunoassay CLIA format. Cortisol (362 Da) cannot support sandwich detection. The competitive format — where sample cortisol competes with Cortisol-BSA (coating antigen) for antibody binding — is the industry standard for clinical cortisol quantification in automated CLIA analysers. Sekbio's reagent set is optimised for the competition kinetics required across the full clinical cortisol range (1–50 μg/dL serum; 0.1–5 ng/mL saliva).
Cortisol measurement in clinical and consumer health applications spans multiple sample types. Serum/plasma: standard morning cortisol, ACTH stimulation test, LDDST post-dexamethasone cortisol. Saliva: midnight salivary cortisol for Cushing's screening (non-invasive, suitable for home collection). 24-hour urine: urinary free cortisol for Cushing's confirmation. Sekbio's competitive CLIA reagents support development across all three sample matrices, enabling multi-format cortisol product lines from a single antibody source.
Cushing's syndrome (total cortisol >22 μg/dL; 24-hour UFC elevated; midnight salivary cortisol >145 ng/dL) and Addison's disease / adrenal insufficiency (morning cortisol <3 μg/dL; abnormal ACTH stimulation test) are the primary clinical indications for cortisol quantification in endocrinology practice. Sekbio's high-affinity IgG2a antibody is characterised to distinguish these clinical decision thresholds with the analytical precision required for regulatory-cleared IVD kit development.
ISO 13485-compliant manufacturing in Shenzhen, China. Full regulatory documentation — CoA, safety data sheet, production records — supports CE-IVD, NMPA, and FDA 510(k) submissions for cortisol immunoassay kits. MOQ 1 mg for R&D; gram-scale OEM supply for kit manufacturing. Cortisol assay kits have broad market application in hospital endocrinology, ICU critical care, consumer stress monitoring, and occupational health programmes. Contact info@sekbio.com for OEM partnership discussions.
Mouse anti-hydrocortisone IgG2a antibody with BSA/OVA conjugates validated for competitive CLIA kit development across endocrinology, critical care, and consumer health.
Cushing's syndrome is caused by prolonged excess cortisol exposure, most commonly from pituitary ACTH-secreting adenoma (Cushing's disease, 70% of cases), adrenal adenoma, or ectopic ACTH production. The Endocrine Society recommends three screening tests: 24-hour urinary free cortisol (UFC), late-night salivary cortisol (midnight salivary cortisol >145 ng/dL indicates hypercortisolism), and the 1 mg overnight low-dose dexamethasone suppression test (post-dex cortisol >1.8 μg/dL = non-suppressed). Sekbio's S17-Cortisol-w901M antibody plus Cortisol-BSA conjugate enable competitive CLIA kit development targeting all three screening test formats. Visit our Products page for the full antibody raw material portfolio.
Addison's disease (primary adrenal insufficiency) and secondary adrenal insufficiency (pituitary or hypothalamic origin) are diagnosed by morning serum cortisol measurement and ACTH stimulation testing. A morning cortisol <3 μg/dL is highly suggestive of adrenal insufficiency; >18 μg/dL after 250 μg ACTH stimulation rules out primary adrenal insufficiency. Adrenal crisis (acute adrenal insufficiency) requires immediate cortisol assay for diagnosis. Competitive CLIA cortisol assays developed using Sekbio's reagent kit support rapid, quantitative cortisol measurement in emergency and routine endocrinology laboratory settings. See our Platforms page for assay development support.
Critical illness-related corticosteroid insufficiency (CIRCI) — also termed relative adrenal insufficiency — is estimated to affect 10–20% of critically ill ICU patients. In septic shock and ARDS, cortisol is an important prognostic biomarker and guides hydrocortisone supplementation therapy. Random total cortisol <10 μg/dL in critically ill patients or delta cortisol <9 μg/dL after ACTH stimulation suggests CIRCI. High-throughput competitive CLIA cortisol assays using Sekbio's IgG2a antibody are suitable for deployment in clinical chemistry analysers in intensive care settings requiring rapid cortisol quantification from serum or plasma samples with a short turnaround time.
Salivary cortisol measurement is a growing non-invasive application for point-of-care stress response monitoring, workplace health programmes, and consumer wellness. Since salivary cortisol directly reflects free (biologically active) serum cortisol, it provides a sensitive HPA axis measurement without venepuncture. Midnight salivary cortisol is the Endocrine Society-recommended Cushing's screening tool; morning and evening salivary cortisol are used for diurnal rhythm assessment in stress research. Competitive salivary cortisol lateral flow or CLIA assays — requiring antibodies with LOD <1 ng/mL saliva — can be developed using Sekbio's high-affinity S17-Cortisol-w901M mAb. Contact info@sekbio.com to discuss saliva cortisol assay development.
Technical and commercial questions from IVD R&D engineers and procurement teams developing competitive cortisol immunoassays.
Cortisol (hydrocortisone) is the primary glucocorticoid hormone produced by the adrenal cortex, molecular weight 362 Da (C₂₁H₃₀O₅). Regulated by the HPA axis, cortisol follows a diurnal secretion pattern (peak: 5–25 μg/dL in the morning; nadir: <5 μg/dL at midnight). It is the key biomarker for diagnosing Cushing's syndrome (hypercortisolism), Addison's disease (adrenal insufficiency), adrenal crisis, critical illness-related corticosteroid insufficiency (CIRCI), and for stress response monitoring. Cortisol CLIA testing is performed across endocrinology, intensive care, and general medicine settings worldwide.
Cortisol is a small-molecule steroid hormone at 362 Da. Sandwich immunoassay requires two antibodies to bind simultaneously to two distinct epitopes on the same antigen. The cortisol molecule is far too small to accommodate simultaneous binding of two IgG molecules (each ~150 kDa). Competitive immunoassay is therefore the only viable format for cortisol: sample cortisol competes with a fixed amount of Cortisol-BSA coating antigen for binding to the anti-cortisol antibody (S17-Cortisol-w901M). Signal is inversely proportional to sample cortisol concentration.
Sekbio supplies three cortisol reagents for competitive CLIA development: (1) S17-Cortisol-w901M — Mouse Anti-Hydrocortisone mAb, IgG2a isotype, ≥90% purity by SDS-PAGE, validated for competitive CLIA; (2) Cortisol-BSA Conjugate — cortisol-bovine serum albumin conjugate for use as competitive CLIA/ELISA coating antigen; (3) Cortisol-3-OVA Conjugate — cortisol-ovalbumin conjugate for immunisation or alternative coating. All available from MOQ 1 mg. Contact info@sekbio.com for datasheets.
Sekbio's cortisol competitive CLIA reagents are suitable for developing assays across multiple sample matrices: serum and plasma (EDTA, heparin) for standard morning cortisol, ACTH stimulation test, and low-dose dexamethasone suppression test; saliva (midnight salivary cortisol for Cushing's screening; diurnal cortisol profiling); and 24-hour urine (urinary free cortisol for Cushing's confirmation). Each matrix may require sample pre-treatment (e.g., saliva centrifugation; urine dilution) — contact info@sekbio.com for application-specific guidance.
MOQ is 1 mg for each of the three products. OEM quantities from 10 mg to gram scale available. Storage for all three products: −20°C long-term; +2–8°C short-term (≤1 month). Formulated in PBS pH 7.4. Avoid repeated freeze/thaw — aliquot before first use. Shelf life: 3 years from manufacturing date. Certificate of Analysis supplied with every shipment. ISO 13485 batch records available for regulatory submission.
Yes. Sekbio supplies the complete cortisol competitive CLIA kit (S17-Cortisol-w901M + Cortisol-BSA Conjugate + Cortisol-3-OVA Conjugate) to OEM IVD manufacturers at gram-scale production quantities. ISO 13485-compliant manufacturing, full regulatory documentation, and technical support for assay optimisation. Applications include automated hospital laboratory cortisol CLIA analysers, point-of-care salivary cortisol stress monitoring devices, and Cushing's/Addison's screening assay kits for CE-IVD, NMPA, and FDA-cleared markets. Contact info@sekbio.com to discuss your cortisol assay project. Visit our Platforms page for antibody development and expression services.
Request the full technical datasheet, competitive CLIA reagent specifications, or discuss OEM supply with our team.