You label your samples, put them in the freezer, come back months later and the writing is gone. It happens constantly in labs across the world. Not because of poor technique. Because the wrong pen was used.

Here is what you need to know.

Why regular permanent markers fail in cold storage

A standard permanent marker works fine at room temperature. Put it into a liquid nitrogen tank at -196°C or a ULT freezer at -80°C and the chemistry falls apart completely.

The ink polymer becomes brittle at extreme cold. The plastic surface of your cryovial contracts at a different rate to the ink sitting on top of it. That difference causes the ink bond to fracture. Add freeze-thaw cycles and the damage compounds with every temperature swing. Then throw in routine ethanol disinfection and whatever ink survived the cold is wiped away entirely.

Three separate failure points. All happening at the same time. And your sample is now unidentifiable.

What actually works

A proper cryogenic permanent ink marker uses a completely different ink formulation. One that stays flexible and bonded at -196°C. One that resists alcohol and solvents. One that survives repeated freeze-thaw cycles without cracking or fading.

It also needs a fine tip. Cryovials and microtubes have tiny writing surfaces. A broad tip turns your sample ID into an unreadable smear. Fine tip gives you clean, legible writing in the space you actually have.

Who needs this

Biobanks storing thousands of samples in LN2 tanks. IVF clinics where patient material traceability is a regulatory requirement. Research labs protecting years of cell line and DNA work. Clinical facilities managing patient samples in deep-freeze storage. Pharmaceutical cold chain operations needing audit-ready identification.

If your samples go below -20°C, this applies to you.

Colour coding: simple and effective

If you store multiple sample types or patient cohorts, coloured cryogenic markers are one of the easiest workflow improvements you can make. Black for primary samples. Blue for duplicates. Red for priority. No SOP rewrite. No new equipment. Just a colour system your whole team follows consistently.

It only works if every colour performs identically. Cheaper markers have weak colour formulations that fail faster than black. The right pen delivers the same permanence across every colour in the range.

The fix

Cryomarker Fine Tip – Black or Coloured – Pk4 is built for exactly this problem. Fine tip precision. Permanent ink rated for LN2 and -80°C storage. Alcohol and solvent resistant. Waterproof and smudge-proof. Works on plastic, glass, metal, cardboard and Teflon. Available in black and colour. Pack of 4 so your whole bench is covered.

Your samples took months to collect. The pen protecting them costs a few pounds. Use the right one.

Shop the Cryomarker Fine Tip Pk4