I have specimens stored in Formalin 10% for more than 6months.( Due to no resident pathologist in Country). Could they still be processed for His to pathology?
In theory, indefinitely. In reality, the subsequent processing depends on the storage conditions: light, temperature, etc. and above all on the type of sample, the size of the sample and the ratio between the sample size and the volume of formalin. Invia commenti Cronologia Salvate Community
Yes, you can do histology and pathology. Some people believe that immuno of some antigens can be slightly reduced but no concrete study has been done in this area. In short, you are OK to do.
The quick answer is that it depends on the prep. The length of fixation can vary depending on histology, antibody work, or in situ hybridization work. We can leave samples in fixative for months and still get good results, however if you are doing an in situ hybridization protocol such as RNAscope, than the most you want to fix is for 24-36 hours due to the amount of cross-linking which has to be broken by pretreatments. We routinely fix overnight and rinse the tissue. Sometimes we even stored in buffer for up to a few days. We fix with 4% paraformaledehyde in 1 x PBS, as previous experience using 3% Gluteraldehyde reduced antigens resulting in a less bright signal.
Histology should be OK.
Immunohistochemistry will probably be OK as well, you could check it if necessary.
Molecular biology might not work, again you can check in the case of need.
If you do immunohistochemistry, you could use Vimentin as a control to make sure the tissue is immunoreactive. Agree with Daniel Stanton comments re: ISH, esp. RNA.
Yes histopathology should not be much of the problem but later if immunohistochemistry is required , need to be cautious.
By the way, this length of time in formalin will almost certainly reduce or eliminate IHC and ISH/FISH staining for breast cancer biomarkers ER/PR/HER2, as will the "cold ischemia" time: the time from removal from the body to placement in formalin, if > 1 hour.
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