Laboratorio

A Practicum for Biomedical Engineering and Technology Management

Chapter 46 - Laboratory Equipment
By David Harrington, PhD

Laboratory equipment in hospitals falls into two main groupings, clinical and research. This chapter concentrates on the clinical laboratory equipment but the same principles of operation are applicable to many research devices. “In clinical settings many functionsthat were done on a separate device(s) have been combined in some of the automated chemistry analyzers. As a BMET you will still need to understand the individual functions even though they are combined into one unit. Also in research settings there tends to be more discrete devices than combination units because of funding and the fact that many of the devices are much older than what are found inclinical settings”. In the simplest terms laboratory equipment perform one or more of the following functions

Function Measure Separate Count Change temperature Display the results Communicate

Description using light, ions, conductivity, weight, and color using electrical or rotational force cells, particles, and events heat or cool on CRT, digital display or paper with other devices orcomputer systems

You should have information from the College of American Pathologists, (www.cap.org) and the American Association of Blood Banks (www.aabb.org) available to you and the departments. Because of high capital costs and changing technology many of the larger devices are not owned by the hospitals but leased or obtained on “reagent rental” basis. Reagent rental is also called per testrental/lease. On non-hospital owned equipment service support is generally part of the lease/rental agreement so we only do incoming and visual inspections. In some cases we may provide a “first look” before calling the outside repair service. First look is limited to verifying error codes that are displayed and clearing any

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external problem that we aretrained to perform. Unless you are specifically trained on the device and authorized by the manufacturer do not try to perform the repairs.
ALL LABORATORY EQUIPMENT SHOULD BE CONSIDERED, AS HAZARDOUS AND PROPER PRECAUTIONS MUST BE OBSERVED WHEN WORKING ON THESE DEVICES.

Clinical analyzers, discrete, continuous flow, automatic, semi-automatic or manual all contain 6 basic functions that can anddo cause problems. Some units may have 2 extra parts that do not generally cause problems, for Biomeds. Those are a system port and a self-check/calibration function.

Figure 1- Clinical Analyzer (table top)

THE BASIC FUNCTIONS

Sample prep the sample may be diluted or mixed with a reagent, or filtered. This may be an automatic process where the samples are placed into special trays orracks and loaded into the analyzer. Sample introduction and transport the prepared sample is aspirated or injected into the analyzer where it may be further diluted or additional reagents added and moved to the detector chamber. In discrete systems this is done with an internal pipetter and with a continuous flow system the samples are separated by air bubbles or water. Detector this can be ionspecific electrodes, photometer, counters, conductance measurements or any combination of these detectors. Processor a microprocessor where information from the detectors is compared, processed and calculations made automatically.

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Flush this automatically cleans the transport system and detector so the next sample is not contaminated by the sample justprocessed. On continuous flow systems the flush is part of the sample separation system. On some units there is an additional flush that occurs after a set number of samples processed or time. Display/printer the results of each test on a sample are displayed on a CRT or printed onto a paper format. Some devices may have both. If the printer is external to the device it may be part of the Biomed...