Specimens submitted for histopathology must be in 10% neutral-buffered formalin.
The ratio of formalin:tissue is preferably 10:1 with a minimum of 5:1.
Collect samples in wide-opening containers — not tubes and narrow-opening containers. Tissue hardens with fixation, and removal of hardened fixed tissue distorts the tissue histology and is a laboratory hazard.
Specimen containers of 180-250 ml are recommended for immune and digestive tissue surveys, and general diagnostics. For larger specimens like bone, or greater specimen numbers use 380-500 ml containers.
Links to vendor of pre-filled formalin containers.
Optional: After fixation (24-48 hours), most formalin can be removed prior to shipping, but leave 5-10 ml to keep the tissue wet. Samples can also be shipped with all of the formalin.
Required: Fixation for 3 days (72 hours) is required by US Custom for entry of specimens into the USA.
Specimen Collection Guides