To the Editor.—
Ten percent aqueous formalin freezes at —11 C (12.2 F) and therefore biopsy specimens exposed to temperatures below this in transport will undergo vacuolation damage from ice crystals. Specimens received by mail during the winter sometimes show sufficient damage from ice crystals to prevent accurate histopathologic examination.Experiments in our laboratory have indicated that prolonged fixation in 10% aqueous formalin before exposure of specimens to freezing and thawing will not prevent or modify ice crystal damage.We have found that Lillie's AAF1 (40% formaldehyde, 10 parts; acetic acid, 5 parts; absolute ethyl alcohol, 85 parts) is a satisfactory fixative mixture for preventing freeze-thaw damage to specimens in transport: (a) Its freezing point is below —30 C (—22 F) and therefore below temperatures commonly encountered in the temperate zone: (b) Its preservation of morphologic detail compares favorably with the preservation of morphologic detail of specimens fixed in
Okun MR, Ellerin P. Prevention of Ice Crystal Damage to Biopsy Specimens in Transport. Arch Dermatol. 1972;105(3):458–459. doi:10.1001/archderm.1972.01620060088022
Coronavirus Resource Center
Customize your JAMA Network experience by selecting one or more topics from the list below.
Create a personal account or sign in to: