Study highlights mentolabial blood collection in rats and hamsters

A new study in the Journal of the American Veterinary Medical Association describes the mentolabial approach as a novel, safe, and effective method of blood collection in rats and Chinese hamsters, pointing to a new access site in the lower lip and chin region for laboratory animal sampling. The abstract says the team prospectively evaluated the technique in rats, Chinese hamsters, and long-tailed chinchillas from February through March 2026, and paired live-animal sampling with dissection and histopathology to better define the underlying anatomy and tissue effects. (pmc.ncbi.nlm.nih.gov)

The work lands in a part of laboratory animal medicine where blood collection technique matters well beyond convenience. Standard rodent sampling sites, including the saphenous, tail, facial or submandibular region, and retro-orbital plexus, are already well described, but each comes with practical and welfare-related limitations depending on species, sample volume, repeat frequency, and staff experience. Institutional guidance commonly emphasizes those tradeoffs, and some programs discourage retro-orbital sampling for serial collections unless there is a strong scientific justification. (research.uky.edu)

There is also precedent for looking to the lower oral or mandibular region as an alternative access point. A 2009 technical report described the labialis mandibularis, or gingival, vein route in rats and mice as a simple option that appeared to reduce unnecessary suffering. Later work in hamsters and guinea pigs found that repeated gingival vein sampling could be performed over multiple weeks without clear adverse clinical, hematologic, or histologic effects, underscoring interest in this region for species with fewer practical venipuncture sites. (ojs.utlib.ee)

What appears new in the JAVMA report is the formal characterization of a mentolabial approach across multiple species, with prospective evaluation and anatomic confirmation. Based on the abstract provided, the study included 10 rats, 10 Chinese hamsters, and 12 long-tailed chinchillas. Even though your story focus is rats and Chinese hamsters, the inclusion of chinchillas suggests the authors were testing whether this access point could extend to other small mammals where tail-based or peripheral sampling may be harder to perform. The study’s emphasis on safety, efficacy, repeatability, dissection, and histopathology is notable because those are the data laboratory animal veterinarians and IACUCs typically need before adopting a new collection method. (ojs.utlib.ee)

Direct outside reaction to this specific 2026 paper was limited in publicly indexed sources at the time of reporting. Still, the broader literature helps explain why the paper may draw attention. Reviews of rodent blood sampling have highlighted how inconsistent terminology and poorly defined head anatomy can complicate training and increase failed attempts, stress, and pain. Comparative welfare studies in mice have likewise shown that collection site choice can influence lesion risk, handling burden, and other welfare indicators, even when several methods are technically feasible. (journals.sagepub.com)

Why it matters: For veterinary professionals in research settings, this study speaks to refinement. If the mentolabial approach proves easy to teach, reproducible across handlers, and compatible with needed sample volumes, it could expand the toolkit for serial sampling while reducing reliance on more controversial or technically demanding sites. That could be especially relevant for Chinese hamsters and other small mammals with limited accessible vessels, and for institutions trying to align blood collection practices with both data quality and animal welfare expectations. (research.uky.edu)

The report may also have crossover relevance beyond the research colony. Earlier exotic animal literature noted that some laboratory-style venipuncture techniques can be objectionable in companion rodent practice, creating interest in alternatives that are both practical and acceptable to clinicians and pet parents. Whether the mentolabial approach translates into broader exotic practice will depend on species-specific anatomy, restraint needs, sample volume, and complication rates, but the concept fits a longer trend toward lower-trauma sampling methods. (sciencedirect.com)

What to watch: The next step is the full paper. Veterinary professionals will want details on blood volumes obtained, number of attempts, restraint or anesthesia requirements, complication rates, histopathology findings, and whether the method performed differently in rats, Chinese hamsters, and chinchillas before deciding how quickly it should move into protocols, training, or clinical use. (pmc.ncbi.nlm.nih.gov)