The use of formalin fixation for tissue processing has been around for a very long time—and that has come with some benefits and drawbacks, says Joshua Greenlee, Senior Product Manager and Laboratory Workflow Productivity Strategist at Sakura Finetek USA. During the NSH Formalin Fixation: Are You Taking it For Granted? webinar, Greenlee points out that although it may be the most common fixative used in histology labs, it’s not necessarily the best because it can be slower than other fixatives and isn’t the safest to work with. On the other hand, formalin is cost-effective and compatible with a wide range of tissue types, so it makes sense that it has become a staple in the lab.
“Even though formalin is not the only fixative, and it's not the best, it does a really good overall job of meeting the check marks that we need to make for fixation,” said Greenlee. “And when you add on the fact that it's been around a long time and it's inexpensive, it's kind of a good way to go—which is why it's become the most widely used.”
However, although formalin is effective, we have to use our time with it wisely.
Time Is of the Essence
Time is a vital variable when it comes to formalin fixation, and it can have a real impact on test results. For example, ischemic time—the time it takes to remove tissue from the body and place it in formalin—can mean the difference between having a sample that’s in good shape for testing and one that’s too degraded to effectively work with.
“We want to do this ideally immediately because as soon as we remove that tissue from the blood supply, we're going to start seeing a breakdown of the components within that tissue specimen,” explained Greenlee. “We want to preserve it as much as possible, so the faster we can get it into formalin, the better off we are.”
Of course, histologists may not have control over how fast a sample is placed in formalin, but Greenlee says keeping this issue top of mind is an effective use of our time.
“An organ or tissue might be removed from the body and then it sits there on a tray or in another container without formalin for a while. Eventually it gets wheeled into another room and is finally put in a jar that has formalin in it, but all the while that tissue has the potential to start to degrade,” he said. “We may or may not have much control over that, but it's one of those things when we're doing our troubleshooting, if everything in the laboratory in terms of fixation is correct, we want to make sure we don't forget there are also those before the laboratory situations that have an impact on fixation.”
A Stitch in Time Saves Nine
Staffing shortages and rising workloads have put a lot of pressure on labs to do more with less—and to do it in the fastest time possible. However, Greenlee warns that it’s important for labs to resist the temptation to cut corners because saving time now may lead to more time spent on a tissue sample later. Despite outside influences, it’s important to remember actual fixation time, which is the amount of time it takes a tissue to fix when it has been submerged in formalin.
To meet the demands of increased workloads and the expectation of faster processing times, the trend among many labs is now to increase the temperature of the fixative. But this technique may be a double-edged sword.
“Increasing the temperature is going to increase the penetration and the fixation rates, but you have to be careful that you're not also increasing the breakdown of the tissue at the same time before the formalin can penetrate and fix,” Greenlee said.
Formalin fixation remains a cornerstone of tissue processing in histology labs due to its cost-effectiveness and compatibility with various tissue types. However, as Joshua Greenlee highlights, it is not without its drawbacks, particularly regarding safety and efficiency. While labs face pressure to increase efficiency amidst staffing shortages, it's essential not to compromise on fixation quality. Ultimately, understanding and optimizing the timing and conditions of formalin fixation can lead to more reliable results and reduced need for reprocessing, underscoring the importance of using our time with formalin wisely. For further insights and strategies, the NSH webinar "Formalin Fixation: Are You Taking it For Granted?" is a valuable resource. #2024#Blog#GeneralAnatomicPathology