Most Common Problems Series

What Is a Tissue Processor?

A tissue processor is a vital instrument in histology labs, used to prepare tissue samples for microscopic examination. When tissue is removed from the body—whether through biopsy or surgery—it needs to be preserved and processed before it can be sliced, stained, and reviewed by a pathologist.

Tissue processors like those from Sakura automate this process. They move tissue samples through a series of chemical stations that remove water, replace it with alcohol, and eventually embed the tissue in paraffin wax. This automation ensures consistency, accuracy, and efficiency across large volumes of samples.

The Most Common Problems We See with Sakura Tissue Processors

At Amtech, we frequently work with labs using Sakura processors, and we often see a few recurring problems. Below are two of the most common issues—and how to troubleshoot them. A list of the tissue Tek Line up can be found below.

Problem #1: Station 3 Fails to Pump In or Out

A frequent user-repairable issue is a failure to pump in or pump out on station 3.

Here’s why it happens: Sakura tissue processors are usually set up with 10% neutral buffered formalin in stations 1 and 2, while station 3 holds alcohol. When formalin and alcohol interact, they produce sodium. Over time, sodium crystallizes and begins to clog the lines and connectors, especially in station 3.

How to Fix It:

The best solution is a hot water flush, which should be part of routine maintenance.

Here’s how to perform the flush:

1. Fill the few water bottle with very hot (not boiling) water.
2. Place the water into station 1 and manually pump in and pump out.
3. Repeat for station 2.
4. For station 3, use fresh hot water and pump in and out 2–3 times.
5. Optionally flush station 4 to remove remaining sodium from the system.
6. Return the water bottle to its standard position and test station 3 again.

If station 3 now pumps freely, the issue is resolved. Sakura recommends performing this flush every 4–5 processing cycles to prevent build-up.

Problem #2: Vacuum or Pressure Failure

Another common issue is a vacuum or pressure failure. This may require formal repair service, but there’s one thing you can check yourself: the retort lid gasket.

If this gasket isn’t sealing properly, the system can’t build or maintain vacuum and pressure.

How to Check It:

1. Start a pump cycle on any station.
2. While it’s running, listen around the retort lid.
3. If you hear hissing sounds, the lid gasket is likely leaking.

In that case, contact Amtech. We can ship you a replacement gasket and walk you through the easy installation process.

Prevent Problems with Routine Maintenance

The key to preventing both of these issues is consistent maintenance. A hot water flush every few cycles can dramatically extend the life of your processor and prevent clogs. Listening for vacuum leaks during pump cycles can help catch gasket issues early.

If you’re experiencing problems with your Sakura processor or just want help with preventive maintenance, Amtech is here to support your lab every step of the way.