Applications: The LAS Story

Applications: Laboratory Advisory System

A knowledge-based decision support system for
the ordering and interpretation of laboratory tests.

The Information Problem

Over the past decade the cost of laboratory testing has increased at a faster rate than most other medical services. Although the unit cost of performing each test has declined relative to inflation, the number of tests ordered has increased significantly.

Ordering protocols have proved to be a very successful approach. Unfortunately, to have an effect on costs and to be workable, such protocols: (a) must address high volume ordering areas, (b) must be amenable to a few, simple rules, and (c) require general agreement amongst clinicians, laboratories, and payment agencies. Such protocols must also ensure that medical care is not compromised through their use.

Thus, while ordering protocols offer a powerful, clinically appropriate approach to utilization control, the number of areas where they can be implemented successfully has been limited by practical constraints.

Ordering and Interpretation

A number of studies have demonstrated that there is great variability amongst physicians in laboratory test ordering for similar clinical problems. It has also been demonstrated that clinicians often do not have all the information necessary for optimal clinical interpretation of the results they receive.

Clinical protocols and educational programmes have provided some help in this area but are limited in their ability to provide a general solution. In particular, the potential of clinical protocols (practise parameters) is hampered by the requirement for them to be both easily remembered and medically acceptable.

Use of Expert Systems

As an interface between the clinician and the laboratory, an Expert System offers the possibility of alleviating these concerns. Expert systems technology has the ability to represent sophisticated and widely applicable protocols as well as the ability to make that information available at the time of ordering.

Laboratory tests are generally ordered by writing the required test on a chart or a laboratory requisition. There is little doubt that, in the future, such orders will be made directly into a computer and the result from the laboratory will be delivered electronically to the physician's office. This will speed up the result turn around time and will allow direct entry of the results into the patient's chart.

The Laboratory Advisory System

The Laboratory Advisory System is designed to reside on a physician's computer with communication links to the laboratory. The system is modular, with each knowledge base addressing a particular diagnostic dilemma. The initial knowledge base advises clinicians on test ordering strategies and on the interpretation of results in the investigation of thyroid function.

The Laboratory Advisory System acts as an intelligent interface between the clinician's office management system and the laboratory information system (LIS). It is built in Acquire^®.

Discussion

The Laboratory Advisory System has the potential for significantly enhancing the manner in which laboratory tests are ordered and interpreted. This is because:

A wider range of applications is possible with Expert Systems than with non-computer models, as they can handle those situations where complexity prevents creating tidy, easily remembered protocols.
An Expert System can be easily modified to accommodate a variety of diagnostic approaches.
As an added feature the Expert System provides an educational function for teaching protocols.
The test results are interpreted ensuring that they are put to optimum use.
The facility for allowing ordering of additional tests to be performed on blood samples held in the laboratory will allow rapid result turnaround without the great expense of recalling the patient for a second venepuncture.
In its full implementation such a system can provide tracking of test orders with the reason for ordering and the results of the analyses.