Template:Formalin exceptions
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The main exceptions to using formalin are mainly:
- Intraoperative consultation.
- Suspected crystals, such as a tophus or other specimen suspicious for gout versus pseudogout. These should be sent in alcohol or dry, since formalin will dissolve the crystals.
- Suspected lymphoproliferative disorders, such as lymph nodes (or other lymphoid aggregates) with a suspicion of lymphoma, where samples are generally put in a special solution for flow cytometry.
- Need for genetic testing, such as some cases of products of conception.
- Cytology specimens, which are preferably sent fresh (such as in red top tubes) to be processed within a few hours. If processing may be after a few hours, put tubes on ice, or add 50% alcohol.[1]
- Need for microbiology evaluation, mainly bacterial culture. For potentially infectious workups, check with the microbiology lab if they have the tissue they need before putting the specimen in formalin.
- Need for immunofluorescence, such as immune complex-mediated disease, where specific preservation will give better test sensitivity.[2]
If you don't know, and if you cannot soon get in touch with anyone who can guide you, specimens can generally be stored in a fridge in the meantime, even overnight if it is late (but make sure to follow-up as soon as possible in the morning). Until then, don't put the specimen in formalin and don't freeze the specimen.
- ↑ . How to send fluid and make good cytology slides. Tufts University.
- ↑ Mubarak M, Kazi Javed I, Kulsoom U, Ishaque M (2012). "Detection of immunoglobulins and complement components in formalin fixed and paraffin embedded renal biopsy material by immunoflourescence technique. ". J Nephropathol 1 (2): 91-100. doi:. PMID 24475396. PMC: 3886135. Archived from the original. .