A test tube holding assembly comprising: a first test tube holder having a pair of first connecting members, the first test tube holder defining a first storage zone and a second storage zone, the first test tube holder being adjustable between a first orientation where the first storage zone of the first test tube holder is accessible and the second storage zone of the first test tube holder is inaccessible when the first test tube holder is in use on a support surface, and a second orientation where the first storage zone of the first test tube holder is inaccessible and the second storage zone of the first test tube holder is accessible when the first test tube holder is in use on a support surface, and wherein the first test tube holder defines a first longitudinal axis extending through the first storage zone and the second storage zone of the first test tube holder, and wherein each connecting member is positioned at an equal axial distance from a corresponding end of the first test tube holder; a second test tube holder having a pair of second connecting members couplable to the pair of first connecting members, the second test tube holder defining a first storage zone and a second storage zone, the second test tube holder being adjustable between a first orientation where the first storage zone of the second test tube holder is accessible and the second storage zone of the second test tube holder is inaccessible when the second test tube holder is in use on a support surface, and a second orientation where the first storage zone of the second test tube holder is inaccessible and the second storage zone of the second test tube holder is accessible when the second test tube holder is in use on a support surface, and wherein the second test tube holder defines a second longitudinal axis extending through the first storage zone and the second storage zone of the second test tube holder, and wherein each connecting member is positioned at an equal axial distance from a corresponding end of the second test tube holder; and wherein the first test tube holder is couplable to the second test tube holder when either test tube holder is in either orientation and wherein the first test tube holder is pivotable relative to the second test tube holder about a third axis that is substantially parallel to the first longitudinal axis and the second longitudinal axis. a first test tube holder having a pair of first connecting members, the first test tube holder defining a first storage zone and a second storage zone, the first test tube holder being adjustable between a first orientation where the first storage zone of the first test tube holder is accessible and the second storage zone of the first test tube holder is inaccessible when the first test tube holder is in use on a support surface, and a second orientation where the first storage zone of the first test tube holder is inaccessible and the second storage zone of the first test tube holder is accessible when the first test tube holder is in use on a support surface, and wherein the first test tube holder defines a first longitudinal axis extending through the first storage zone and the second storage zone of the first test tube holder, and wherein each connecting member is positioned at an equal axial distance from a corresponding end of the first test tube holder; a second test tube holder having a pair of second connecting members couplable to the pair of first connecting members, the second test tube holder defining a first storage zone and a second storage zone, the second test tube holder being adjustable between a first orientation where the first storage zone of the second test tube holder is accessible and the second storage zone of the second test tube holder is inaccessible when the second test tube holder is in use on a support surface, and a second orientation where the first storage zone of the second test tube holder is inaccessible and the second storage zone of the second test tube holder is accessible when the second test tube holder is in use on a support surface, and wherein the second test tube holder defines a second longitudinal axis extending through the first storage zone and the second storage zone of the second test tube holder, and wherein each connecting member is positioned at an equal axial distance from a corresponding end of the second test tube holder; and wherein the first test tube holder is couplable to the second test tube holder when either test tube holder is in either orientation and wherein the first test tube holder is pivotable relative to the second test tube holder about a third axis that is substantially parallel to the first longitudinal axis and the second longitudinal axis.