Conventional SBF (simulated/synthetic body fluid) solutions are buffered at pH 7.4 degrees C and 37 degrees C using 50mM Tris [(HOCH2)(3)CNH2]. Tris is not present in human blood or metabolism and its high concentration makes it the third major component of SBF solutions. All three crystalline polymorphs of calcium carbonate (calcite, aragonite and vaterite) have never been tested simultaneously in an SBF solution. This study presents the SBF-testing of the particles of these polymorphs at 37 degrees C in Na-L-lactate (22mM)-buffered Lac-SBF solution. While the calcite rhombohedra remained completely inert in the solution, vaterite spherulites and aragonite needles accrued apatitic CaP (calcium phosphate) deposits on their surfaces. Mg-doped (1050ppm) synthetic aragonite particles did not transform into calcite for 96h in the Lac-SBF solution while increasing their BET surface area by about 560% via the apatitic CaP deposits. Given the well-established use of calcite powders in CaP cement formulations, synthetic aragonite particles may be a potential replacement for calcite due to their rapid response to blood plasma-like solutions in between 24 and 48h at 37 degrees C.