A review of automated slide stainers for IHC and ISH

Medical Laboratory Observer, Jan, 2008 by Joe Myers

A word on continuous/random access

The expressions "continuous access" and "random access" are sometimes misunderstood when used in the context of IHC/ISH slide-staining systems, primarily because these terms do not accurately describe the processes involved in IHC/ISH. This terminology is essentially borrowed from the field of chemistry and immunoassay analyzers, where test completion is measured in minutes, not hours.

Random access, in the case of IHC/ISH instruments, refers to the ability of a system to perform any test within its memory at any time, a capability that is shared by most systems. An exception to this rule exists, for example, when the protocol template used within an Autostainer system does not permit application of a second (i.e., batch chromogen). Continuous access refers to a system's ability to accept new specimens for testing on an ongoing basis, without regard for the quantity or complexity of the procedures that are already in progress. In this case, it is important to point out that many IHC/ISH instruments that are promoted as being capable of continuous processing are, in fact, limited by other conventions. For example, in those instruments where slides are arranged in vertically oriented trays, such as Vision Biosystem's Bond, additional slides cannot be added to the same tray once the processing of a tray of slides has begun.

Consumables and cost estimates

No evaluation of automated IHC/ISH systems would be complete without a determination of the costs associated with near- and long-term operation. This is especially true because of the wide variation in the cost of consumable products. The importance of using reliable, cost-effective reagents cannot be overemphasized because, once an instrument has been installed and end-users have become comfortable with the integration of the system into their workflow, the primary issues of concern are obtaining consistent staining results and managing costs. A useful cost estimate (sample shown in Table 3) provided by IHC/ISH system vendors will normally include all of the various reagents and other consumables employed to produce results (especially the unique and costly dispensers, vials, and covertiles required by some systems), as well as the cost of maintenance and repair service (especially post-warranty preventive maintenance contracts). Persons involved in the evaluation of a system should not be afraid to ask a vendor to provide them with a comprehensive cost estimate. One should not fall victim the phrase "All you have to do agree to purchase ('X' quantity of) detection kit(s) each month," since--as many people have learned--the cost of detection kits represents only a small portion of the total costs that your lab will likely incur. One should also be cautious of vendor representatives who state that "Providing a comprehensive cost estimate would be difficult for us to do." The fact is that the vendor can and should provide interested parties with this information, unless they are afraid that knowing the total cost of consumables will have a negative impact on their ability to make the sale.