Laboratory Labels: The Ultimate Guide

We all have experienced the frustration of being unable to read the handwritten label on a tube or a bottle. It's easy to blame a poorly written laboratory label on a lab mate. But when you find yourself unable to interpret a label, it's time to change your labeling system and make it part of your laboratory information management strategy.

I once was eager to do as many experiments as fast as possible, sometimes leaving my tubes poorly labeled or completely unlabeled. My research mentors frequently told me how important proper labeling is. “Label everything before it leaves your hands.” But it wasn’t until I was holding two unlabeled tubes both containing tiny volumes of clear liquid—completely confused about which was which—did I understand why. Now I label everything in lab. I make less mistakes and have increased productivity.

Proper labeling of everything in lab is essential to a lab’s success. Since so many labs are struggling to develop reliable labeling strategies, we put together this guide for Laboratory Labels.

Follow these links to skip to a specific section:

• Improve your lab by printing labels
• How to achieve ultimate lab labeling
• Essential components of laboratory labels
• Choosing the right laboratory label printer
• Six label printers for laboratories that will fit your budget

Consider the freezer box, pictured above. You know they are Amanda’s samples, but they are missing crucial information. Are they DNA or RNA solutions? Are they safe or hazardous? What experiment did they come from? Even if a sample came from an intermediate step of an experiment, what if Amanda needs to go back and check this sample? Which Amanda, Amanda K. or Amanda B.?

Improve your lab by printing labels

Much can be gained when every sample in lab has a clear, detailed label. Here are three main factors about how your lab will improve when using clear labels:

1. Save time and money

One objection to labeling everything in lab is that it is time consuming and printed adhesive labels are expensive. It does not have to be. In fact, the opposite can be true: labeling can save your lab time and money.

Think about the long run. Inadequate labeling can lead to making mistakes that are costly – both in time and money. Mistaking samples for one another can lead to interpreting false results,  remaking reagents or solutions, and worst of all needing to repeat an experiment. Avoid these situations by labeling each tube thoroughly. Increase your productivity and success, as well as save money.

One way to expedite labeling is to use a label printer. Once purchased and implemented, the printed labels will always be clearly legible and fit all requisite information onto samples of any size. Some label printers are portable and handheld. This allows label design and printing to happen all at the lab bench, minimizing time. Software for several label printers can save labels for quick reprinting of common labels. In fact, some processes can be sped up with a label printer, such as labeling batches of tubes, such as serial repeats or numerous aliquots.

2. Increase the lab’s teamwork

An easy mistake is to label things in a way that you (but only you) can understand. For instance, researchers (myself included when I’m not careful) will use acronyms or leave out key information, labeling things as quickly as possible. However, think about the long run. Each lab label should be detailed enough for a different researcher or lab member to know its identity and contents. This allows lab members to share samples or work together on projects.

3. Practice important safety measures

Lastly, proper labeling is important for experiments and generating data, but even more so for safety. An unlabeled or mislabeled tube could contain something dangerous to your health. Once, my lab mate left an unlabeled dish of cells sitting on the lab bench near the sink. I was cleaning that part of lab. I knew my lab mates sometimes treated cells with arsenic—too toxic to wash down the drain. Feeling like I was somewhat overreacting but not wanting to make a dangerous mistake, I treated the contents of the dish with extreme caution as if it was this poison. Later, I found out that the unlabeled dish was, in fact, treated with arsenic and accidentally left out.

Leaving unlabeled or poorly labeled samples can be dangerous to yourself or your lab mates, like it was for me. Stay safe, efficient, organized and successful by properly labeling everything in your lab.

Chemicals with hand written labels compromise lab safety.

How to achieve ultimate lab labeling

In the wise words of my research mentor, “Label everything before it leaves your hands.” Do you want to have label minimal, adequate, or ultimate lab labels?

Minimal lab labeling

Label all samples generated in the lab with the information listed above. A common mistake is to only label samples going into long term storage, such as the cryopreservation tubes that won't be thawed for years tucked away in a freezer box. However, illegible or obscure labels on short-term or intermediary samples can be problematic. Take, for example, not being able to read the labels of DNA mini-prep spin columns or a sequencing library. Such a lack of labeling clarity will most likely lead to remade samples or repeated experiments.

Adequate lab labeling

Label all samples and reagents. Ask everyone to write the date and their initials on all reagents when they make or first use them. This is especially important when using perishable supplies. Labels on reagents can be useful information during troubleshooting. For example, if a particular lab member’s reagents were prepared incorrectly or become contaminated, or if a reagent surpasses its recommended “use within X days”.

Ultimate lab labeling

Label all samples, supplies, locations, and equipment with printed, adhesive labels. Use a Laboratory Information Management System (LIMS) to categorize each sample with a unique ID. Incorporate a barcodes or QR codes to access sample information more quickly. With this level of labeling, individual stocks and aliquots can be tracked through an experiment or order. If an experiment fails, the individual components can be tracked down and tested. Lastly, label locations—room, shelf, or freezer box—with barcodes or unique IDs. This strategy allows other researchers, lab technicians, and personnel to find things more easily.

Essential components of laboratory labels

Here is the information that needs to be on each lab label:

• What it is
• Concentration
• Who prepared the sample
• Date of sample preparation or collection
• Warning information (if it contains hazardous materials)

Extra label information for DNA:

• What type of DNA is it? Plasmid, PCR amplicon, or digested fragment?
• How was it prepared? Mini-prep, PCR cleanup,
• What is the promoter? Gene? Other important sequence regions?

Extra label information for cells:

• Strain/cell type
• Mutations (if applicable)
• Antibiotic resistance/selection marker
• Passage number (mammalian cells)
• Preferred media (mammalian cells)
• Cell density

Here is how to make even better labels. Quick tips for best label practices:

• Use a consistent, standard order for this information. For example, always using the order in the previous section. Better yet, have everyone in the lab use the same system.
• Use a standard format for the date. I always use an 8-digit code, YYYYMMDD (year, month, day) without spaces, slashes or dashes. Unlike other date formats, this one increases chronologically, so the largest number is always the newest sample.
• If using a label printer, save label templates for commonly used information. For instance, if you commonly make a PBS buffer solution, save all information in a pre-made format and simply change the date for a new batch.
• Lastly, in the wise words of my research mentor, “Label everything before it leaves your hands.”

Solutions with handwritten labels may be incomplete or difficult to read.

Choosing the right laboratory label printer

Label printers suitable for laboratories come in several brands, varieties and features. The cost quickly jumps from hundreds to thousands of dollars. The optimal printer depends on your lab environment. Ask yourself these questions to determine which label printer features fit your specific needs.

Will you be printing graphics?

If only text is needed, you can avoid extra costs by purchasing a simpler label printer, such as a handheld printer with a built-in keyboard. Printing graphics, QR or barcodes, or color images require more sophisticated printer and software.

Inkjet, laser, or thermal?

Though this may seem trivial, the decision of printer ink is in fact critically important beyond the initial difference in price of the printers.

How durable?

First – and most importantly – to consider is which ink suits your lab’s needs. What types of chemicals or conditions will your labels be exposed to? If the labels will be subjected to moisture, solvents, or extreme temperatures, make sure that the type of ink used will remain readable. For extreme solvents, such as xylene, alcohol, and hematoxylin, thermal transfer printing proves most durable and the safest option. Lastly, labels can be made of different materials (for instance, paper versus plastic) and are resistant to different conditions. Make sure the labels you need are available for your printer of choice.

Printing in color?

Do you need to print in color, perhaps, for a categorization scheme or hazmat labels? Thermal printers do not have color capability – choose an inkjet or laser printer. Inkjet, thermal, and laser printers each have different capabilities and long-term and short-term costs.

What about portability?

Is your lab space large enough that you will need a portable handheld printer? Or will you have a stationary label printing station, for instance, if there are several personnel who will share the same label printer? Deciding between a handheld or stationary label printer takes into account several factors.

Handheld label printers range from using a portable keyboard for text-only labels to having barcode printing capability with a built-in scanner. They are generally less expensive. Stationary label printers can connect to a computer using a USB or Bluetooth and come with a software program for designing labels. Other stationary label printers are completely stand-alone units, controlled internally versus by a computer. Though more expensive, they can generally handle a greater printing load.

Other features…

It’s up to you how to decide the needs of your labeling system. Do you want your printer to store label files or transfer label files via a USB? Do you have a computer in your lab available to connect to and control your printer? Or do you want a printer that works independently to design labels? Buttons or a touch screen? Label printers have various assortments of these features. Pick the version that best addresses the needs of your lab and integrates into your lab workflow.

Six label printers for laboratories that will fit your budget

Upgrading your laboratory labeling system doesn’t need to break the bank. Once expensive, label printers are now affordable enough for small-scale purposes, like organizing and categorizing things in a lab. We researched the printers that are best for laboratories from the market's leading brands for you to compare. Here are six label printers for your lab that are affordable.

Zebra is one of the leading brands of this market. Here are two Zebra printers that are best for laboratory labeling purposes.

1. Zebra’s GC420™ Desktop Printer

The GC420 is a small desktop thermal transfer printer. It prints labels up to 4 inches wide, and can use different fonts or graphics, including logos and barcodes. As a thermal transfer printer, it prints in one ink color. The GC420 connects to a computer via USB. ZebraDesign software is free and will handle all your basic label printing needs. It can be upgraded to the Pro version for a one-time fee. Several Zebra accessories can be added on, such as a keyboard with a small screen to turn your printer into a printing station or a rechargeable battery and stand to increase portability of your printer.

2. Zebra's ZD410 Direct Thermal Desktop Printer

ZD series printers are the fastest in our list, printing at 6 inches per second. The ZD410 line has a special laboratory and healthcare model, which is the same technical specifications but made of disinfectant-ready plastic and other healthcare privacy features. They print labels up to 2.2-inch-wide, quite smaller than the GC420 series. They are direct thermal printers and print black ink. ZD series printers can connect to a computer via either USB or Bluetooth. The ZebraDesign software (described above) can incorporate barcodes and images as well as text. They have a battery to power it when not plugged in, which increases their portability. Zebra accessories, such as a keyboard or a rechargeable battery, are available for this model.

Brother is another leading brand. They offer small desktop printers for monochromatic or color labels. Specifically, the Brother P-Touch series is specifically designed to make mobile printing as simple and easy as possible.

3. The Brother P-touch PTD600VP

This P-touch series printer is an extremely usable, inexpensive solution for 1 inch tape labels. This label printer can be connected to a computer or used stand-alone with its full keyboard and full-color graphical display. Templates and images, including logos or barcodes, can be stored in the P-touch’s memory to help save time with reprinting. Plus, the labels, called TZe tape, are durable and colorful, and cheaper than label rolls.

Brady is another popular brand of label printers. Though on the pricy side, Brady printers offer several features that you might decide are worth the extra cost. For instance, the BradyPrinter M611 Mobile Label Printer is portable, connecting via Wi-Fi or Bluetooth and can be controlled with a smartphone app.

4. Brady's BBP12 Label Printer

The BBP12 is a small, sturdy desktop printer with a color-LCD display. Though the BBP12 label printer costs more than similar models from other brands, you get what you pay for. It can connect via ethernet to a network or USB to a specific computer workstation. As a thermal transfer printer, it prints with black ink on a maximum label width of 4.6 inches. It is capable of printing text, as well as graphics and barcodes. Brady printers use Labelmark printer software, which has very good reviews. Unfortunately, accessing this software costs hundreds of dollars.

Though a new, smaller company, DYMO is fast-becoming a leader in the label printer industry. They specialize in simple, inexpensive, small-scale products, which can be ideal for a small lab setting.

5. The Dymo LabelWriter® 450

The LabelWriter 450 is a very affordable desktop label printer option. A direct thermal printer, this model prints text, barcodes, logos, and graphics in black ink. The LabelWriter 450 connects to a computer workstation via USB cable. Label text and designs can be created through DYMO’s free label software for PC, Mac, or even Android. Though the software has mixed reviews for its ease-of-use, it has time-saving features such as the ability to import label information from programs like Outlook or Excel.

Epson is a well-known leader in the printer industry. However, since they focus on commercial uses for label printers, the choices for a lab label printer are slim.

6. The Epson TM-L90 Plus Label and Barcode Printer

The TM-L90 is another compact desktop label printer option. It is simple, small, and efficient. As a thermal line printer, it is quite fast, capable of speeds up to 5.9 inches per second. It can print labels of up to 3.14 inches in black ink. It connects to a computer workstation via USB or Bluetooth. And to keep the lab bench clear, it has an optional wall hanging bracket.