Microprocessors in pathology

Articles on the use of computer systems, both mainframe and minicomputer, in pathology laboratories have been prolific over the last few years. It might therefore be assumed that a discussion on the role ofthe microprocessor is essentially similar but on a smaller and humbler scale. I hope to show, however, that the microprocessor has a very distinct and significant role in the pathology department-it is increasingly becoming an indispensable component or 'tool' in analytical methodology and instrumentation. The essential factor in distinguishing the microprocessor or microcomputer (in simple terms a microprocessor plus an operating system, input and output facilities and user memory) from the mini-or mainframe computer is its relatively low cost. The price of a fully comprehensive computer system for many medium and small-sized laboratories is prohibitive, but the 'micro' has changed this cost perspective and puts into the hands of the laboratory worker, or gives to an individual analytical procedure, tremendous computing power than can truly be said to be personal. The computer is under the control of and can be developed by the analyst him/herself for specifically tailored situations and needs that can develop commensurately with changes in the wider laboratory environment. It also means that much of the analytical computation, data handling and formatting , quality control, and the generation ofhard-copy results and work-lists can be performed off-line by a local workstation. This can improve the turnover ti.me for obtaining results. In many applications the microprocessor is 'embedded' within an instrument so that it controls certain features of the instrument but is 'invisible' to the user. From current laboratory magazines it would appear that for an instrument just to have a microprocessor gives it a distinct selling advantage. A summary of some uses that micros are being put to in laboratory practice include the following. These may be pre-programmed, when a fixed sequence ofevents is followed, or may involve reactive processes in which some form of feedback loop is involved. For this sensors and transducers monitor and modify the environment via out-put/input ports. A simple example is the micro-controlled histology tissue processor in which tissue held in a rack is sequentially immersed in baths of fluid at controlled temperatures for varying times. Another example of mechanical control is the programmable X-Y sampler. Test, standard and control solutions from a variety of racks can be sampled and dispensed, in a different order into an arrangement of racks …