Canine marrow study highlights IHC impact of fixation choices
CURRENT BRIEF VERSION: Bone marrow processing choices can materially change what veterinary pathologists see on canine immunohistochemistry, according to a new Veterinary Pathology study examining fixation and demineralization methods in postmortem sternal marrow from dogs with spontaneous disease. The study compared acetic acid-zinc-formalin with 10% neutral-buffered formalin, then tested formic acid, hydrochloric acid, and EDTA demineralization across different time points. In parallel work from the same research group, EDTA outperformed acid decalcifiers for marrow histomorphology, while neutral-buffered formalin and acetic acid-zinc-formalin performed similarly for morphology. The authors said those findings can help guide labs choosing protocols for bone marrow samples that may need downstream testing. Outside marrow pathology, other bone-derived tissues have also shown that EDTA-based workflows can support strong DNA recovery: one recent Animals paper reported successful genotyping from all 60 deer antler and prepared trophy skull samples using an EDTA-based digestion and extraction protocol, underscoring the broader value of gentler mineralized-tissue processing when molecular testing is part of the plan. (pmc.ncbi.nlm.nih.gov)
Why it matters: For veterinary professionals, this is a preanalytic issue with direct diagnostic consequences. Immunohistochemistry is highly sensitive to fixation timing, fixative chemistry, decalcification method, and processing duration, and expert guidance has long warned that decalcification type and duration can alter antigen preservation and stain performance. In canine bone and marrow specimens, that matters because labs often need to balance turnaround time against preservation of morphology, antigenicity, and, in some cases, molecular testing options. EDTA is slower than acid decalcifiers, but related marrow data from the same group showed better tissue preservation with EDTA, while acid-based approaches were associated with poorer performance on downstream DNA amplification. Broader work in mineralized tissues points in the same direction: an EDTA-buffer, proteinase K, and organic solvent protocol generated high-quality DNA and complete microsatellite genotypes from deer antlers and processed trophy skulls without cryogenic grinding or commercial kits. (euromabnet.com)
What to watch: Whether diagnostic labs update marrow and bone biopsy protocols toward EDTA-based demineralization, especially for cases where IHC or molecular follow-up is likely, and whether simplified EDTA-based extraction approaches broaden molecular testing options for other hard tissues. (pmc.ncbi.nlm.nih.gov)