VB12 Intrinsic Factor & BSA Tracer Conjugate

Name: Vitamin B12 Intrinsic Factor & BSA Conjugate
Brand: Sekbio

Product Overview

What is Vitamin B12 Intrinsic Factor? — A Definition for IVD Developers

Vitamin B12 (cobalamin) is the largest and most structurally complex vitamin, and the only one that contains a metal ion — cobalt, at the centre of its corrin ring. Intrinsic Factor (IF) is a glycoprotein secreted by gastric parietal cells that binds native vitamin B12 with very high affinity, shielding it from proteolytic degradation and mediating its absorption across the ileal mucosa. Because IF is the vitamin's own physiological binding partner rather than a raised antibody, purified Intrinsic Factor is the established reference capture reagent for quantitative serum VB12 immunoassays.

Sekbio supplies two matched VB12 raw materials built for competitive immunoassay design: VB12-B03, a self-developed, high-purity Intrinsic Factor protein (99.17% by HPLC), and VB12bsa-03, a cobalamin-BSA carrier-protein conjugate used as the competing tracer or immunogen. Together they form a complete capture/tracer system that our R&D team has continuously refined for flexible deployment across fluorescence lateral-flow (FIA), chemiluminescence (CLIA), and ELISA platforms. Since IF deficiency or anti-IF autoantibodies are themselves a leading cause of pernicious anemia, sourcing a consistently high-affinity IF protein is central to assay reliability. For the chemistry behind choosing a tracer or immunogen derivative, see our vitamin B12 derivative selection guide.

Competitive Immunoassay Native Binding-Protein Capture ISO 13485 Manufacturer OEM Raw Material Supply

Intrinsic Factor Specifications (VB12-B03)

Catalog No.VB12-B03

Lot No.E01001

Concentration4.60 mg/mL

Relative Purity99.17% (HPLC)

AppearanceClear and transparent

BufferH2O

Storage−20°C ± 5°C

Intended UseLFA / CLIA / ELISA

Shelf Life3 years from manufacture

PlatformsFIA / CLIA / ELISA

Complete Product Catalog

VB12 Raw Materials — All SKUs

Intrinsic Factor capture protein and BSA tracer conjugate for a complete vitamin B12 competitive immunoassay system.

Catalog No.	Product Name	Lot No.	Appearance	Identification / Purity	Storage	Intended Use
VB12-B03	Vitamin B12 Intrinsic Factor	E01001	Clear and transparent liquid, 4.60 mg/mL	99.17% (HPLC)	−20°C ± 5°C	Capture reagent — LFA / CLIA / ELISA
VB12bsa-03	Vitamin B12-BSA Conjugate	D06001	Red or pink solid	UV Max 361 nm; SDS-PAGE electrophoresis — pure	2–8°C	Tracer / immunogen — CLIA / ELISA / LFA

VB12bsa-03 is soluble in pure water or PBS buffer; centrifuge before opening to ensure complete recovery of vial contents. Both products are supplied for research or further manufacturing use, with a Certificate of Analysis issued per lot. Contact info@sekbio.com for bulk OEM pricing and lot availability.

Vitamin B12 cobalamin molecular structure showing the cobalt-centered corrin ring recognized by Intrinsic Factor

Vitamin B12 (cobalamin) — the only vitamin containing a metal ion, bound at its corrin ring by Intrinsic Factor during physiological absorption and by IF in a competitive immunoassay.

Why Choose Sekbio VB12 Raw Materials

Built for High-Sensitivity Competitive Immunoassay Development

Six analytical and commercial advantages behind Sekbio's self-developed Intrinsic Factor and BSA conjugate.

High-Purity Intrinsic Factor

VB12-B03 is purified to 99.17% by HPLC and supplied at a concentrated 4.60 mg/mL in H2O buffer — high enough purity and concentration to minimise non-specific background and support flexible bead- or plate-coating protocols.

Identity-Confirmed BSA Conjugate

VB12bsa-03 identity and purity are confirmed by UV absorbance at 361 nm and SDS-PAGE electrophoresis, giving OEM developers a well-characterised tracer/immunogen conjugate ready for labeling and immunoassay integration.

Superior Comparative Sensitivity

In internal head-to-head testing, Sekbio's IF + BSA-conjugate pair reached an S/N of 272.88 at 2000 pg/mL antigen versus 6.60 for a competitor's Intrinsic Factor and derivative pair — roughly 41x stronger signal suppression at the top of the tested range.

Multi-Platform Flexibility

The same IF and conjugate chemistry has been validated in a four-step competitive chemiluminescence format and is compatible with fluorescence lateral-flow (FIA) and ELISA competitive assay designs, giving OEM teams platform choice without re-sourcing raw materials.

Complete Matched Capture/Tracer Pair

Intrinsic Factor (capture) and VB12-BSA conjugate (competing tracer) are supplied as a pre-characterised pair with a documented reagent composition and four-step reaction protocol, shortening the path from raw material to working assay.

OEM Bulk Supply, ISO 13485

Manufactured under ISO 13485 QMS in Shenzhen, China. Both raw materials are available in OEM quantities with a Certificate of Analysis per lot and consistent lot-to-lot performance for production-scale kit manufacturing.

Verified Performance

Analytical Data

Data generated using Sekbio's VB12-B03 Intrinsic Factor and VB12bsa-03 BSA conjugate in a four-step competitive chemiluminescence format (AE label, magnetic-bead separation).

1 Comparative Sensitivity — Sekbio vs. Competitor Reference

Sekbio's self-developed Intrinsic Factor and VB12-BSA conjugate were benchmarked head-to-head against a competitor's Intrinsic Factor and derivative pair, under identical antigen concentrations and reaction conditions. Sekbio's pair shows markedly stronger competitive signal suppression at every concentration tested, reaching a signal-to-noise ratio of 272.88 at 2000 pg/mL versus 6.60 for the competitor pair — consistent with higher binding affinity between Sekbio's IF protein and native cobalamin.

Antigen Conc. (pg/mL)	Sekbio T/C (avg.)	Sekbio S/N	Competitor T/C (avg.)	Competitor S/N
0	3.033	1.00	6.624	1.00
10	3.004	1.12	6.621	1.05
30	2.481	1.42	6.232	1.07
100	2.346	1.59	5.699	1.09
1000	0.083	37.92	2.645	2.22
2000	0.0125	272.88	0.938	6.60
T = test-line/RLU signal; C = control signal; T/C = signal ratio (mean of n=2 replicates per concentration). Internal comparative study; not an independent third-party verification.

2 VB12 Chemiluminescence Bulk Reagent — Reference Composition (AE Platform)

Built from Sekbio's IF and BSA-conjugate raw materials, this reference reagent set demonstrates a complete four-step competitive chemiluminescence assay using acridinium-ester (AE) labeling and magnetic-bead separation.

Reagent	Name	Storage
Ra	VB12 Reagent — Magnetic Bead (IF-coated)	2–8°C
Rb	VB12 Reagent 2 — Treatment Solution 2	2–8°C
Rc	VB12 Reagent 1 — Treatment Solution 1	2–8°C
Rd	VB12 Reagent — AE-Labeled Tracer	2–8°C
Optional	VB12 Standard (lyophilized)	2–8°C

Method Comparison vs. Roche

The finished VB12 chemiluminescence bulk reagent built from Sekbio's IF and BSA-conjugate raw materials was benchmarked against the Roche reference platform across the clinical range. Regression analysis shows a slope of 1.0341 and an intercept of 3.30 pg/mL — close to ideal 1:1 agreement — with R² = 0.9541, indicating strong correlation between the two methods.

Method comparison scatter plot of Sekbio VB12 chemiluminescence reagent versus Roche, showing linear regression y = 1.0341x + 3.3038 and R-squared 0.9541

Sekbio VB12 (pg/mL) vs. Roche (pg/mL) across paired samples. Linear regression: y = 1.0341x + 3.3038, R² = 0.9541.

3 Reaction Protocol — Four-Step Competitive Assay

Sample pretreatment releases VB12 from endogenous serum binding proteins before it competes with the AE-labeled tracer for a limited pool of IF-coated magnetic beads.

Step	Reaction Detail	Washing
1	Add 15 µL Rc + 15 µL sample for pre-treatment; incubate 15 min	No wash
2	Add 15 µL Rb; incubate 5 min	No wash
3	Add 30 µL Rd; incubate 15 min	No wash
4	Add 30 µL Ra; incubate 5 min	Wash
Result	Add 100 µL Pre-Trigger (A) and 100 µL Trigger (B); read RLU	—

4 Six-Point Calibration Curve

A six-point calibration series spanning 0–1967.31 pg/mL demonstrates the expected inverse dose-response of a competitive assay: RLU signal falls, and S/N rises, as antigen concentration increases.

Calibrator	Concentration (pg/mL)	Average RLU	S/N
S0 — Blank	0.00	1,720,880	1.00
S1	74.02	1,388,486	1.24
S2	187.77	986,626	1.74
S3	453.58	545,514	3.15
S4	1060.43	246,603	6.98
S5	1967.31	113,125	15.21
RLU = relative light units, duplicate measurement average. S/N = blank RLU ÷ sample RLU.

5 Dilution Linearity

A six-point dilution series of a high-concentration sample (X6, 1983.80 pg/mL undiluted) was serially diluted and measured against the calibration curve. Recovery across the mid-to-high range (X3–X6) stayed within approximately 92% of expected concentration; recovery at the lowest dilution tested (X2, 20% of X6) was 78%, indicating dilution linearity is best characterised above roughly 400 pg/mL for this reagent configuration.

Sample	Dilution Ratio	Expected Conc. (pg/mL)	Measured Conc. (pg/mL)	Recovery
X1	0.0	0.00	0.00	—
X2	0.2	396.76	310.27	78.2%
X3	0.4	793.52	728.47	91.8%
X4	0.6	1190.28	1102.29	92.6%
X5	0.8	1587.04	1459.25	92.0%
X6	1.0	1983.80	1983.80	100% (reference)
X6 is the undiluted reference sample used to back-calculate expected concentration at each dilution ratio; average of triplicate RLU readings.

Use Cases

VB12 Raw Material Applications in IVD Development

Intrinsic Factor and BSA conjugate validated for hematology diagnostics and OEM immunoassay development.

Pernicious Anemia & VB12 Deficiency Diagnosis

Serum VB12 quantification supported by IF-based capture chemistry is central to diagnosing pernicious anemia, whether caused by IF deficiency, anti-IF autoantibodies, or malabsorption. Low VB12 also underlies macrocytic anemia and neurological deficits requiring prompt laboratory confirmation.

Nutritional & Neurological Screening

VB12 testing supports screening in elderly patients, individuals on restrictive or vegan diets, and those with gastrointestinal disorders (atrophic gastritis, bariatric surgery, Crohn's disease) that impair IF secretion or ileal absorption.

CLIA Analyzer Reagent Kit OEM Development

The documented four-step reagent composition and reaction protocol give CLIA analyzer manufacturers a validated starting point for building a VB12 assay kit around Sekbio's IF and BSA-conjugate raw materials, with AE chemiluminescence detection.

LFA / FIA Rapid Test Development

The same IF and conjugate chemistry is compatible with fluorescence lateral-flow (FIA) cassette formats, supporting point-of-care VB12 rapid test development for OEM manufacturers targeting decentralised or resource-limited testing settings.

FAQ

Frequently Asked Questions — VB12 Intrinsic Factor & BSA Conjugate

Technical and commercial questions from IVD R&D engineers and procurement teams.

What is Vitamin B12 Intrinsic Factor and why is it required for VB12 immunoassays?

Intrinsic Factor (IF) is a glycoprotein secreted by gastric parietal cells that binds native vitamin B12 with very high affinity, protecting it from proteolytic degradation and mediating its absorption across the ileal mucosa. In competitive immunoassay design, purified IF is used as the analyte-specific capture protein because, unlike a raised antibody, it is the vitamin's native physiological binding partner and recognises all major circulating cobalamin forms with high specificity. Deficient IF secretion or anti-IF autoantibodies are themselves a leading cause of pernicious anemia, which is why IF-based capture is the reference approach for serum VB12 testing.

What is the VB12-BSA conjugate and how is it used in a competitive assay?

VB12bsa-03 is a cobalamin-BSA carrier-protein conjugate supplied as a red or pink solid, identified by UV absorbance at 361 nm and confirmed pure by SDS-PAGE electrophoresis. A labeled form of the conjugate is added at a fixed concentration and competes with the patient sample's free vitamin B12 for a limited number of IF binding sites, so assay signal is inversely proportional to sample VB12 concentration. The same conjugate chemistry can also serve as an immunogen for raising anti-B12 antibodies.

What catalog numbers and lot data are available for Sekbio's VB12 raw materials?

Sekbio supplies VB12-B03 Intrinsic Factor (Lot E01001, 4.60 mg/mL, 99.17% purity by HPLC, manufactured 2024-01-04, expires 2027-01-03) and VB12bsa-03 BSA tracer conjugate (Lot D06001, manufactured 2023-06-26, expires 2026-06-25). A Certificate of Analysis is issued with every lot shipped.

How does Sekbio's VB12 Intrinsic Factor compare in sensitivity to competitor reagents?

In a head-to-head internal comparison under identical four-step competitive chemiluminescence conditions, Sekbio's IF and BSA-conjugate pair reached an S/N of 272.88 at 2000 pg/mL antigen versus 6.60 for a competitor's Intrinsic Factor and derivative pair — roughly 41x stronger signal suppression at the top of the tested range, and about 17x stronger at 1000 pg/mL (37.92 vs. 2.22). See the Performance Data section above for the full comparison (n=2 replicates per concentration).

Which IVD platforms are these VB12 raw materials validated for?

The IF protein and BSA conjugate are validated in a four-step competitive chemiluminescence immunoassay using acridinium-ester (AE) labeling and magnetic-bead separation, and the underlying binding chemistry is compatible with fluorescence lateral-flow (FIA/LFA) and competitive ELISA formats. Both raw materials are available individually for OEM developers building a custom protocol, or as a matched pair.

What is the storage condition and shelf life for these products?

Intrinsic Factor (VB12-B03) is supplied in H2O buffer and should be stored at −20°C ± 5°C, avoiding repeated freeze/thaw cycles; shelf life is 3 years from the manufacturing date. VB12-BSA conjugate (VB12bsa-03) is a solid stored at 2–8°C, soluble in pure water or PBS buffer. Both are for research or further manufacturing use, with a Certificate of Analysis per lot.

VB12 Intrinsic Factor & BSA Conjugate