Records a culture notebook should hold

A culture notebook is how a line outlives the person who thawed it. The next user needs to know what the cells are, how many times they have been subcultured, what they were fed, what they looked like, whether anyone looked for contamination, and where a frozen backup sits. Without those fields the incubator still holds flasks. It does not hold a continuable experiment. The surrounding practice is in mammalian cell culture for research labs. This page is the record itself, applied to the moment someone else has to pick up the work. A photograph in the hero is a person writing. The writing is the data.

What another person has to be able to do

The test of a page is practical. Someone who did not seed the flask should be able to decide whether to passage, whether to treat, or whether to leave the vessel alone. That decision needs the line name as it appears on the vial, not only a nickname, the source, and the passage counted under a stated rule. It needs the date and either a split ratio or a seeding density. It needs the medium formulation and the serum lot if serum is in use. It needs a sentence of observation and the last contamination check. It needs a freezer location that a second person can find.

Public guides, including the ATCC culture guides and notes from the European Collection of Cell Cultures, are starting descriptions. They are not your page. If your vial's label and the public page disagree, the notebook should say which one you followed and why. Identity doubts belong with resources such as ICLAC resources, which explain why a name is not an authentication.

Fields, and the future question each one answers

Line name and source answer "are these the cells in the method section?" Source means the collection, the laboratory, or the tissue procedure, plus a catalogue identifier if one was printed on the vial you received. Do not invent an identifier the supplier did not provide. Authentication status answers "have we checked that name?" Record pending, passed against a named reference, or failed. A failed check takes the line out of the shared story. Do not leave the field blank and hope the morphology is distinctive. Morphology is a weak identity test.

Passage number answers "how far is this population from the stock we trust?" State the starting passage from the supplier and the rule: increment by one at each subculture, for example. Date answers "when was this row true?" A date without a passage, or a passage without a date, breaks the chain as soon as two people work on alternate days.

Split ratio or seeding density answers "what did we actually do?" Ratio is enough when you did not count, if you say you did not count. Density needs a count, a volume and the growth area. Confluence estimated by eye answers "why did we split today?" It does not replace the passage. Medium formulation and serum lot answer "can we buy or mix the same liquid?" Write the basal name, any supplement, the serum percentage and the lot code from the bottle. A lot that is smeared by condensation should be copied onto the page before the bottle goes into a humid fridge.

Observations answer "did the cells still look like themselves?" One sentence is enough: spread monolayer, more floaters than yesterday, clumps after dissociation. Contamination checks answer "are we pretending clarity is a test?" Record mycoplasma method and date, and any bacterial or fungal suspicion, including negative visual checks on a schedule. Freezer inventory location answers "where is the vial that saves us if this flask is lost?" Box, rack, and a label string that matches the page. A mental map of the tank is not an inventory.

How to fill the page when the day goes wrong

Start the row before you open the flask, with line, passage and intended action. Finish it before you leave the room, with what you actually did. If the count failed, write the ratio and the word estimated. If the serum lot code is unreadable, quarantine that bottle from the record and do not copy a code from a different bottle because the colour matches.

Branch when a required field has no honest value. Missing authentication on a newly arrived line means the status is pending and the line stays in whatever quarantine your institution set. It does not mean you write "looks right". Missing freezer location means you do not yet have a backup. Make a token freeze on the schedule you use, or say that no freeze exists, so nobody discovers the gap during a contamination. A mycoplasma test that was not run is recorded as not run. Clarity of the medium is not a substitute result.

If two people share the line, the page is the handover. A chat message that says "fed them" fails the test. The row needs the formulation. Templates on protocols.io are examples of structure. Your institution may already bind you to a particular notebook or electronic system. Use that system. The field list still applies inside it.

Gaps that strand the next user

The common gap is a passage that lives in one person's memory, with beautiful photos and no number. The next user either restarts the count at one, which erases age, or refuses to touch the flask. Another gap is a medium written as "the usual". Usual shifts when a lot changes and when a stand-in mixes the buffer from a different card. A third gap is a freezer box labelled with a nickname that matches nothing on the page. In a crash, that box is where time is lost.

A control that fails is a record, not a reason to skip the row. If cells were over-confluent because nobody wrote Friday's cover, Monday's note should say so. If a mycoplasma assay failed its own control, write that the assay is invalid and is being repeated. Do not write negative in the meantime.

The notebook is not a permit

Research records support research continuity. They do not authorise clinical use, a diagnostic claim or a biosafety level. The containment of the line, the consent status of primary material, and who may open the notebook are institutional decisions. Keep those approvals where your system requires them. This page does not replace a laboratory safety manual. Do not copy donor-identifying detail into a casual bench book if your rules forbid it. A culture record can name a de-identified sample code your institution issued.

Humidity, a warm shipment, and a specification

Humid incubators and humid storerooms lift ink and fog bottle labels. Copy lot codes onto the page while they are still legible, and note if a shipment arrived warm, who received the cold box, and whether that lot was kept off the main line. Heat does not change the fields. It makes delay expensive. When the record shows a repeated medium family, a vessel surface and a serum class, you have the bones of a sourcing note. How to turn a laboratory need into an enquiry is set out in how to write a laboratory sourcing enquiry. Point the note at the laboratory consumables catalogue for everyday classes and at the academic research reference if the work sits in a university brief. The quote request can carry the specification those fields already contain. A discussion of that specification does not mean someone else will keep your line, and it does not invent a stock position. The notebook remains yours to complete.