There are numerous, though not that many considerations to take into account when properly selecting a test tube rack for your laboratory. Because a test tube’s bottom is rounded, and it will not stand by itself, a test tube rack is a very convenient necessity in even a minimally equipped lab. 

The construction of a test tube rack might be determined by it use i.e. corrosion resistant material. The four main rack construction materials are plastic, polyethylene, metal and wood. Plastic, being very economical is often used; polyethylene for acid and corrosion resistance, metal is more sturdy, and better wearing under certain circumstances, while wood might be chosen for aesthetics. There are even cardboard throwaway racks. 

The test tube capacity could be as little as 4 to 8, or as many as 60 to 80, or more. Some test tube racks are stack-able. They are available in a variety of colors, just like test tubes. Some people value aesthetics, even in a laboratory, and color coordination is a consideration. 

A test tube rack may also have pins on which the tubes may be inverted to drain and dry after cleaning. This can be particularly convenient if the drainage pins are on the same rack on which the test tubes are stored. Considering that test tube racks are relatively a rather inexpensive piece of equipment, most likely you would be able to choose and purchase exactly the model that would be most appropriate for your lab i.e. a rack constructed of special noncorrosive material, a particularly large rack, a wooden rack etc.  

Performing a search on the Internet among the many manufacturers and sellers of test tube racks, and the appropriately matching test tubes, will provide you with a seemingly endless choice from which obviously you could find exactly the test tube rack or racks that would be a perfect fit for your lab.