Evaluation of the convergence site as a refinement over the facial vein for chin bleed of CD1 female mice.

We evaluated the convergence between the facial vein and the submental/labialis-inferior as an alternative site to the facial vein in the submental region for blood collection in mice. Three groups of CD1 female mice (n = 10 mice/group) were used for three blood collection occasions from the convergence site. A fourth blood collection was performed from the convergence site for one group and the facial vein for the other two. Total blood removed, collection success rate, and clinical signs were evaluated. Total blood removed, and collection success rate was stable across collection occasions at the convergence site. When compared with the facial vein, the convergence site showed milder tissue damage, a higher collection success rate and a larger amount of total blood removed. Results indicate that the convergence site is more effective than the facial vein site for bleeding mice, but has an increased risk of overcollection, thus is recommended for a target volume of less than 10% of circulating blood volume.