The maintenance and storage of Histology paraffin blocks and slides is a never-ending challenge that exists throughout the life of a laboratory. Many labs confront this challenge with strategic planning, but unfortunately all too often it is out of desperation. The luxury of having perfect planning allows you to consider options such as dedicating a room in the facility or using off-site storage. The challenge of just finding a space might make you consider options such as a lower-level service room or basement just to move them from the laboratory. There are basic minimal standards on how long clinically diagnostic case slides and blocks must be maintained, but many labs have their own extended standard of how many years ‘they’ decide to keep these stored beyond regulatory compliance. Oftentimes this is based on the chance of potential litigation at some point, or on additional innovations in diagnostic testing. Thus some facilities keep them indefinitely.
Each laboratory makes their own decision as to their priority of using the more inexpensive option such as materials made with corrugated cardboard, or units made with a more durable and permanent material such as high density-molded polystyrene plastic. Both types of storage are extremely efficient and satisfy a need for organized storage. Both can accommodate small storage units that are space efficient for in-lab use. The divergence in choice comes primarily in the areas of cost, durability and future archive plans.
The all corrugated cardboard type storage units can be found to accommodate paraffin blocks or slides, as seen in the image on the right. Most are sturdy, strong, and can manage the weight of their respective block and slide capacities. Some companies use partially recycled cardboard combined with new board for strong, environmentally conscious products. These are less expensive, use a small footprint of bench space, and can be easily transported from one area to another. Index marker cards can then be used to help segment numerical counts as well as locate removed slides/blocks that were sent out for consultation. An additional important point to consider with corrugated storage units is the very nature of the material. While corrugated storage is capable of lasting 20-30 years in optimum conditions, it can be susceptible to humidity and dampness in less desirable storage areas.
With the addition of high impact polystyrene plastic trays (right) in the drawers, overall strength of the storage unit is increased. Another plus for using plastic trays is the ability to later move them to steel cabinets, (B) shown below, without having to refile the slides/blocks.
Additional storage options are steel shelving units to house the corrugated units and assist in stacking and increase ease of use in retrieval. Note the individual shelves holding the block/slide storage drawers, as well as the organizing shelf in the middle. This type of storage can be utilized both inside a lab with available space and outside archive areas.
Moving into the product realm of most durable and permanent, these types of units may seem slightly more expensive, but benefits such as a higher storage capacity, lifetime durability, and stronger material making it impact resistant; these actually make them more cost effective than less expensive temporary systems. The last two images side-by-side below both demonstrate durability and permanency. The first unit (A) is a hard-plastic storage system housing 6-tray internal storage levels. It is interlocking and stackable and holds a total capacity of 1,500 blocks. The second image (B) is considered the ‘next generation in High Volume Storage Units’: The High-Density Storage Cabinet. These are heavy-duty metal cabinets with full suspension drawers that hold up to 400 lbs. each. The cabinet in its larger size has a total capacity of 75,600 blocks and 264,000 slides. The greatest benefit of the HD cabinets is in slide archives. Pathologists/researchers have easy access to a much broader range of current and archived cases without the inconvenience of lower level or off-site storage delays.
Whatever the decision of the laboratory, it is an assurance to know that you have options to suit your personal storage needs. Some companies will even custom-design cabinets for your preference. Therefore, it is advised that each lab take their time and research the various product samples in the market. Long-term block and slide storage is something that will be with you for a considerable while…, so choose wisely.