Avoiding invented catalogue codes

A catalogue code is an identity only when it appears on a document the laboratory can open. A string reconstructed from memory, from a photograph you no longer have, or from the rhythm of a typical part number is not a code. It is a guess, and a guess in the shape of a code is worse than a plain description, because people stop questioning it. This protocol is how to notice that and how to order by specification instead. It sits inside how to write a laboratory sourcing enquiry. The file goes through laboratory procurement.

Plasticware classes, including tubes, are in the laboratory plasticware catalogue and are discussed in when to use plastic tubes, tips, and plates. Nothing below invents a code to illustrate the point. The worked description is 50 mL sterile conical tubes, racked. University groups can start from academic research. The quotation page and the contact page are where the specification is sent.

Identity is a document you can open

You are deciding whether a short alphanumeric string is allowed to stand for a product. The decision rule is physical: can you open the source and see those characters on it? Sources that count are a label in your hand, a certificate, a packing list in the laboratory file, or a product page you can open and read today. Sources that do not count are memory, a conference slide, a chat message, a methods sentence that paraphrased the product, and a code you assembled because it "looks like" the maker's style.

Protocols.io and journal methods are good places to learn what a protocol was trying to do. They are unstable places to copy a commercial identity. Catalogues are revised. Regional lists differ. A single digit transcribed wrong points at a different pack, a different sterile claim, or nothing at all. NIST's metrology pages are about stated measurements and documented procedures. The same habit applies here: an identifier without a document is not yet a measurement of identity.

The control fails when nobody can produce the source. The branch is mandatory. Delete the code. Continue with a specification. Do not leave the guessed string "just in case", and do not replace it with a made-up example that later readers might order.

The workflow

Start from the scientific need, in one sentence. Example: you need tubes for spinning 50 mL of culture or for storing a buffer, capped, sterile, supplied in a rack so the bench stays clean. That sentence is the job. It is not yet an order.

Next, search the laboratory file for a document that already identifies the last tube you accepted. If you find a packing list or a label and the description still matches the job, you may copy the code that is printed there and you cite the document. If you do not find it, you do not search your memory as a backup source. You write the specification in the next section and you send that.

When a reply offers a code, treat the reply as a new document. The code in the quotation is an identity for what the seller is offering, once you can read it on that quotation. It becomes part of your records when you file the quotation. It does not become a code you are allowed to invent on the next order if the file is later lost. If the file is lost, you return to the specification.

On receipt, copy codes only from the goods and the papers in the box. If the container prints no code, the receipt record says that no code was printed. Records to keep after a delivery is the companion for that moment, once you are writing the receipt rather than the enquiry.

Order by specification

A specification names what a person can check without a private catalogue. For the tube example, write the features as separate lines so a reply can meet or refuse each one.

The description: 50 mL sterile conical tubes, racked. Material: polypropylene, unless the SOP names another polymer. Graduation: marked, if you need to read volume on the tube. Cap: screw cap that seals. Sterile claim: stated on a document that will arrive with the goods. Racked: in a rack, not loose in a bag. Centrifuge rating: suitable for the speed your rotor manual allows, if you will spin them. Temperature: the storage or freezing rating if the SOP freezes the tube. Quantity: number of tubes, as a pack count. Acceptance: seal of the sterile pack intact, tubes are the stated volume, racked as specified, and the sterile claim is on the accompanying document.

None of those lines requires a code. A seller can answer them. You can fail them on receipt. A code may appear in the answer. When it does, file it with the quotation as the seller's identifier for that offer. Your acceptance still follows the lines, not the mere presence of a string.

Glassware specified by accuracy class follows the same pattern and is described in choosing laboratory glassware. A class is a specification. A remembered glassware code is not.

A worked description with no code

Put the enquiry in sentences a stores colleague can read.

Job: aliquot and spin buffers and culture supernatants up to 50 mL. Item: 50 mL sterile conical tubes, racked. Polymer: polypropylene. Cap: screw cap. Claim: sterile, as stated on the document shipped with the tubes. Pack: racked. Performance: may be centrifuged in the laboratory's existing 50 mL rotor at the speed that rotor's manual allows; the laboratory will check fit before release. Out of scope: filters, media, and any enzyme. Documents: the sterile claim on a sheet or certificate that names these tubes. Acceptance: intact sterile barrier, conical 50 mL form, racked, cap seals, and a fit check in the rotor.

That paragraph is complete enough to quote. It contains no letter-number code. If someone later finds a code on a real document, they may add it underneath and cite the document. They may not "improve" the paragraph by typing a plausible string.

The branch when someone pastes a remembered code

You will see this in drafts. A student adds a code because a previous order "had numbers". Ask, in writing: which document, and can you open it now? If yes, attach it or quote the surrounding description so the code and the words can be checked together. If no, delete the code before the enquiry is sent.

Partial memory is the same branch. "It started with the maker's initials" is not a source. Manufacturers reuse shapes of codes across product families. A string that is almost right can be a different volume or a non-sterile pack. The specification in plain language is safer than a near miss.

If a published method prints a code, open the method, record the citation, and still confirm the code on a current document if you intend to rely on it. If you cannot confirm it, order by the scientific description the method gives, and drop the code. The branch is not "use it because a paper had it". Papers are not catalogues.

Failure modes

The first failure is a confident wrong code. The order looks professional, the goods that arrive match the code and not the experiment, and the argument becomes about who typed it. The specification would have made the mismatch visible as an exception. A bare code hides it until the bench.

The second failure is a code from another region's list, copied from a collaborator's paper. The product family exists and the pack or the sterile claim differs. Citing the collaborator is not opening a document. Write the features you need and let the quotation name what is offered where you are.

The third failure is filling a blank on the receipt with the code you wish had been printed. That corrupts the delivery record. If it was not printed, it was not printed. ISO 9001 is a public standard about documented information; the relevant habit is that records say what was observed. A blank lot or a missing code is an observation.

Safety and research use

A missing code does not change the hazard of the contents. Read the safety data sheet that did arrive, and follow institutional biosafety rules for anything biological. Biosafety basics for research benches keeps containment with the institution. Ordering 50 mL sterile conical tubes, racked, is a research consumable request. It is not a clinical device order, and this page is not medical advice.

Sterile, on the specification, means the claim you asked to see on a document. It does not mean the tubes are free of nuclease unless you wrote that second claim. Autoclaves and what sterilisation does not do explains why a sterile word is not every other purity word. If the assay needs nuclease control, add it as its own line, still without inventing a code.

Old paperwork in a shared store

Shared stores accumulate packing lists with stained corners and codes that referred to a pack the manufacturer later resized. Humidity and time make some of those lists hard to read. If you cannot read the characters, you do not have a code. If you can read them, check the words next to them against the tube you need now. A power cut or a move that separates the list from the cupboard is another way a code becomes memory. The specification taped inside the cupboard door, written as 50 mL sterile conical tubes, racked, plus the sterile claim and the rotor fit, survives better than a private string. When you next enquire, send that description.

The enquiry

Send the plain specification. If and only if a document you can open shows a code, include that code and name the document. Ask the quotation to describe the offered goods in the same features: volume, polymer, sterile claim, racked, and rotor fit. Ask it not to rely on a code alone.

Use the quotation page when you are submitting selected products and can place the specification in additional requirements. If a selected record has nothing to show, that page says No catalogue code, and the words you typed in additional requirements carry the identity. Use the contact page when you are sending the specification as the message itself. Keep a copy. The code you are willing to defend later is one you can still open.