A QR label saves you the walk back to the laptop. Instead of finding a bottle in the freezer, remembering what it was, and then searching for it in Inventory, you point your phone at the sticker and the item is already on screen with its actions ready. Working from the bench rather than the desk is part of the point.
What the code on a container is
Every label carries a short code: a string of letters and numbers that Labsistant issues and that points at one specific thing in your lab. The code is the whole label. The QR square is just a convenient way for a camera to read it, which is why you can also type the code by hand when a sticker is scratched or frosted over.
A few things follow from that:
- One live label per item. Asking for a label again gives you back the one that already exists rather than a second one. A single container cannot end up with two live codes on two different stickers.
- The code is not the item's name. It carries no reagent name, lot number, or quantity. Everything a scan shows you is read live from Labsistant at the moment you scan, so a label printed months ago still shows today's quantity.
- A label can be revoked. A revoked label stays readable but stops opening anything, which is what you want when a container is decontaminated and reused.
Codes exist for inventory items, storage locations, and scheduled experiments. Today the button that makes one lives on inventory items.
Make a label and put it on the container
Labels are made on the web app, not on the phone.
- Open Inventory and click the item to open its detail panel.
- Scroll to QR Label.
- Click Generate QR label. The short code appears, along with a version number. If this item already has a live label, you get that same one back rather than a new one.
- Choose which form of the code goes on the sticker:
- Copy web link gives you a link that opens the item.
- Copy app link gives you a link that opens straight into the Labsistant app on a phone.
- Turn that link into a QR square using whatever label printer or QR tool your lab already uses, and print it.
Generating a label needs the same access as working with the item: a Researcher or above in the lab, or anyone who can already reach that particular item.
Two habits worth keeping:
- Print the short code as text underneath the square. Cameras struggle with frost, condensation, and curved 1.5 mL tubes. A readable code underneath means the label still works when the square does not.
- Put the label where it survives. Cap tops get wiped, and a label on the bottom of a box faces the shelf. The side of a container, above the fill line, is usually the one spot that stays both clean and visible.
If you are labelling a freezer, a shelf, or a box rather than a container, read Create a storage location and Grid boxes and slots first, so the thing you are labelling exists in Labsistant before you stick anything on it.
Scan it on your phone
- Open the Labsistant app and go to Scan.
- Tap Camera. The first time, your phone asks for camera permission. Labsistant cannot open the camera until you allow it, and you can change that later in your phone's settings.
- Hold the square in frame. The lookup starts on its own, so there is no shutter button to press.
- If the camera cannot read the square, type the short code into the QR code field and tap Look up. That is the same lookup, and it is often faster than fighting with a reflection.
Once the label opens, the item appears with what you can do to it from where you are standing. What those actions mean, and which to reach for, is covered in Update, consume, or adjust an item's quantity.
Scanning the same label twice in a row does nothing, on purpose. The app tells you it has already scanned that one, so a camera that catches the sticker on the way past cannot repeat your last action.
If you scan while your phone has no signal, a label you have scanned before on that phone still opens from what is stored on the device. Anything that changes inventory waits until you are back online, because the quantity on screen has to be confirmed by the server before it can be changed.
When a scan finds nothing
A scan that comes back empty is usually telling you something specific rather than failing at random. Match the message:
| What Labsistant says | What it means | What to do |
|---|---|---|
| QR code not found | No label you can see matches that code. | Check the printed code and type it in. If it is right, either the label was never generated, or it belongs to a lab you are not in. |
| This label has been revoked | The label opened, but it is no longer the live one for anything. | Generate a fresh label for the item and replace the sticker. |
| You do not have access to this QR label | Your sign-in was not accepted for the lookup, usually an expired session. This is about you, not about the label. | Sign out, sign back in, and scan again. |
| Scan a Labsistant label or enter the short code | The square was read fine, but it is not one of ours. | You have scanned a vendor barcode or a shipping label. Labsistant only reads codes it issued. |
| Offline, not cached on this device yet | You are offline and have not scanned this label on this phone before. | Get back in range and scan it again. |
| That took too long | The lookup did not come back in time. | Check the connection and scan the label again. |
The one worth pausing on is QR code not found, because it covers two different situations on purpose. The first is a sticker and Labsistant genuinely disagreeing: a container relabelled from an old roll, a sticker printed from a code that was later revoked, or a label moved from one container to another. The fix for all three is the same, which is to generate a fresh label for the item you are actually holding and replace the sticker rather than trying to make the old code work.
The second is a label from a lab you are not a member of. You get the same not found wording rather than a message telling you the code exists but is off limits, and that is deliberate. Someone holding a stack of stickers should not be able to work out which of them are real by watching which error comes back. So a code that fails to resolve is not proof the label is broken. If a colleague can scan the same sticker and you cannot, the difference is lab membership, not the label.