Recombinant protein supplier: a selection guide for IVD developers
If you are searching for a recombinant protein supplier, the useful question is not who has the longest catalogue — it is which supplier can hand you material whose purity, endotoxin level and lot behaviour you can actually defend to a reviewer. This page sets out what to verify, how the different supplier types compare, and how we answer each point ourselves.
We supply recombinant antigens, matched antibodies and biological buffers for in-vitro diagnostic development and research. Everything below applies to the material we ship, and you are welcome to hold us to it in writing before a first order.
A qualification checklist for recombinant protein suppliers
Seven questions worth asking before you approve a supplier. Each one has a short answer that tells you whether the supplier measures what they sell, or only resells it.
| Purity: method and value, reported separately | A single ">95%" figure tells you very little. Ask for HPLC and SDS-PAGE results stated separately, with the lot number they belong to. Denaturing gels and native HPLC measure different things, and a supplier that reports both is usually also the one that will answer a technical question. |
|---|---|
| Endotoxin level, in EU/µg | Critical if the material touches cells or enters a sensitive immunoassay. Recombinant protein expressed in E. coli is not automatically low-endotoxin, and a supplier that does not report it may simply not measure it. State your threshold in the enquiry rather than assuming it is met. |
| Host-cell protein and expression-system disclosure | The expression system (E. coli, insect cell, mammalian, plasma-derived) determines glycosylation, refolding behaviour and what purification carryover is plausible. It should be stated, not inferred. |
| Lot-to-lot consistency and lot reservation | A reorder that arrives as a different lot can force re-validation of your calibrator or control. Ask whether the same lot can be reserved, and whether the supplier tracks which lot the previous shipments used. |
| The documentation package | A lot-specific Certificate of Analysis should carry the lot number, test methods, results and the release specification. SDS, MS data and a certificate of origin are commonly needed by university procurement. |
| Format and formulation | Carrier-free, tagged or untagged, lyophilised or liquid, buffer and preservative content — these change how the material behaves in coating, conjugation and calibrator preparation. Confirm before ordering, not after. |
| Shipping conditions and import reality | Temperature control in transit, dry-ice handling and the customs paperwork for your country. A price that looks lower is not lower if the shipment is held at clearance for a week. |
Match the antigen format to your assay platform
The same analyte can be the wrong material if the format does not fit the platform. Use this as a starting point, then confirm with an evaluation sample on your own system.
| Platform | Format that usually works | Why it matters |
|---|---|---|
| Chemiluminescent immunoassay (CLIA) | Carrier-free, high purity, low endotoxin | Matrix interference and calibrator stability dominate; carrier proteins can compete with the analyte. |
| ELISA / microplate assays | Purified antigen, carrier-free for coating | Coating efficiency depends on formulation; a carrier or excess tag can block the plate surface. |
| Lateral flow / rapid test | Antigen and matched antibody pairs | Pair performance on the membrane, not in solution, is what matters — evaluation samples first. |
| Immunoturbidimetric assays | Antigen at defined concentration, matched antibody | Reaction kinetics and concentration tolerance drive reagent formulation. |
| Calibrators and controls | High-purity, carrier-free, lot-reserved | Reproducibility of the source lot is the whole point; a changing lot means re-validation. |
| Cell-based and functional work | Low endotoxin, carrier-free, defined buffer | Endotoxin and preservative content directly affect viability and readout. |
We also help with capture / detection pair matching and will quote evaluation quantities so you can prove a combination on your bench before scaling.
Supplier types compared — and where we sit
There is no single best type of supplier; there is a best fit for your stage. We are honest about which one we are, because it determines exactly what you should verify with us.
| Supplier type | What you gain | What to watch |
|---|---|---|
| Production partner / manufacturer | Lowest unit cost at scale; direct technical access | Several accounts, several CoA formats; minimum orders can be high; you own the import process |
| Specialist distributor | Curated range, local stock, faster delivery | Limited range; you may not know which production site material came from |
| Trading company (that is us) | One contact, one invoice, one CoA format across the range; flexible quantities from one vial upward | We do not run the production line — so ask for the production-partner documentation package |
In practice, most laboratories run a hybrid: a production partner for large-volume reagents once a lot is qualified, and a trading supplier like us for the breadth, the small evaluation quantities and the single documentation format across several analytes.
What our Certificate of Analysis contains
Every batch ships with a lot-specific CoA. If a field you need is missing, ask — an incomplete CoA is a problem we would rather fix before you order than after.
| Product identity | Name, catalogue reference, lot number |
|---|---|
| Purity | Method (HPLC / SDS-PAGE) and result for that lot |
| Concentration | Value, method and reconstitution volume where lyophilised |
| Appearance / form | Lyophilised or liquid, buffer and preservative content |
| Endotoxin | Where specified, in EU/µg |
| Release statement | Specification the lot was released against |
How a first order usually goes
| 1. Enquiry | Send the product, intended application, quantity and destination. If you are unsure of the format, say what platform you are building for and we will suggest one. |
|---|---|
| 2. Specification confirmation | We confirm availability, format, lead time and the documentation package in writing — before you place an order. |
| 3. Quotation | A quotation is issued per quantity, grade and destination, typically within one business day of a complete enquiry. |
| 4. Evaluation sample | Where useful, a small quantity is supplied so you can qualify the lot against your own assay. |
| 5. Bulk and reorder | Larger quantities and, where stock allows, the same qualified lot for consistent reorders. |
Questions buyers ask before a first order
What kind of supplier are you — manufacturer or distributor?
We are a trading company: we source, qualify and supply recombinant proteins and IVD raw materials from established production partners, and we hold the commercial and documentation responsibility for what we ship. That means one contact, one invoice and one CoA format across the whole range — rather than several accounts with several production sites. We state this openly because it changes what you should verify: ask us for the lot-specific CoA and the production-partner documentation package before your first order.
Can you supply an evaluation or pilot quantity before we commit?
Yes. Evaluation and pilot sizes are available so you can qualify a lot against your existing assay before placing a larger order. Mention that it is an evaluation when you enquire and we will quote accordingly.
What is the minimum order quantity?
Minimum order quantity depends on the product, the format and the destination, and is stated on your quotation. For evaluation work the practical minimum is usually one vial; bulk and custom packaging are quoted separately.
What documentation is supplied with each lot?
A lot-specific Certificate of Analysis and an SDS with every batch, plus a commercial invoice and packing list. HPLC and MS data, a certificate of origin and any additional quality documents are available on request. See our quality documentation page for the fields a CoA should contain.
Can we keep the same lot for later reorders?
Where stock allows, yes. A consistent lot removes a full re-validation cycle from assay development, so it is worth asking at the time of your first order rather than when you reorder.
How are the materials shipped?
Lyophilised proteins and plasma-derived antigens are shipped by international express courier with appropriate temperature control — frozen or on dry ice where the product requires it. Biological buffers and preservatives ship at ambient temperature. Tracking is provided for every shipment.
What are the typical lead times?
In-stock items are dispatched within 3–5 business days. Custom production, bulk quantities and items shipped under specific temperature conditions usually take two to four weeks. The lead time is confirmed on your quotation before you commit.
Do you supply outside the EU and the US?
Yes — we ship worldwide. Customs documentation, commercial invoice and, where required, a certificate of origin accompany the shipment. Import duties and local clearance are the responsibility of the receiving laboratory.
Can you source an antigen that is not in your catalogue?
In many cases yes. We supply a wider range of recombinant proteins, antigens and antibodies than the catalogue lists, including custom expression and bulk quantities. Send the specification and we will confirm availability.
Are the products GMP or suitable for clinical use?
No. All materials are supplied for research use and in-vitro diagnostic development only. They are not manufactured under GMP, they are not a finished diagnostic, and they are not intended for human or animal therapeutic use.
For research use and in-vitro diagnostic development only. Not for human or animal therapeutic use. Materials are not manufactured under GMP and are not finished diagnostic products.
Request a quote or evaluation sample
Send the product, the application and the quantity — we confirm availability, format, documentation and lead time in writing before you order.