Abstract: A micro sample tube is disclosed which is of a standard size on the exterior, but which has a reduced internal volume. A slope of an inner wall of the sample tube is a second order or higher curve, and is preferably a circle. Dead volume is reduced, and standard barcode labels can be used, due to the restricted internal dimensions and standard external dimensions. The curved inner wall of the sample tube, and an internal length of the sample tube which is the same as a conventional tube, reduces the likelihood of a sample probe of an automated analyzer impacting on an inner surface of the sample tube and potentially gouging the tube and/or damaging the automated probe. In a preferred embodiment, fins extend around said tube for reduced weight and improved heat transfer of the micro sample tube.