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Smooth Sailing In the Lab

Automation in Medical Laboratory Diagnostics

The majority of people have given a blood or urine sample for preventive medical check-ups prior to operations or for diagnostic purposes.  The samples are placed in small test tubes, labelled, taken to the laboratory and – a couple of days later –the patient is informed of the result that provide information regarding blood, sugar, liver or kidney values.  Most people don’t stop to think where the laboratory is located in which the tests are analyzed and, what is the analyzing process?Medical sample analyses

The analysis of blood and urine samples occurs in highly-specialized laboratories with state-of-the-art automation technology performing thousands of analyses every day.  As with many other automation tasks, high-performance micro drives play a key role due to their high-quality efficiency, high torque in a small design, reliability and low power consumption.

Even today, many laboratories performing medical sample analyses still use manual distribution systems.  The process starts first when the data for the incoming samples is captured.  The samples are then placed in racks in batches, carried by employees to the various analysis stations and, if necessary, re-sorted from time to time for further analyses.  With thousands or even tens of thousands of material samples per day, this is not only a laborious and monotonous task, but one that is prone to errors. Any troubleshooting then necessitates additional time and effort.  More time is required if individual samples need special handling, because they must pass through several stations for step-wise diagnostics.  The same applies for the dilution of samples for certain analyses or for splitting samples for different analyses; the production of so-called aliquots. Disruptions to an orderly workflow are, therefore, inevitable.  This process is made more difficult by the current trend towards collecting only one sample from patients for all of the necessary analyses where possible.  With this approach, the problem will become more acute in the future, particularly through the centralization of laboratory services.

How Does An Automatic Sample Distribution System Work?

The use of practically oriented automation technology that frees employees from monotonous activities and eliminates sources of error will become unavoidable in modern laboratories.  An automatic sample transport system ideally transports the samples directly to the appropriate analysis system and, while doing so, performs other tasks along the way: following delivery, the sample identification can be used to plan and optimize the route through the laboratory, whereby many parameters can be taken into account, such as the type of container, the preparation, the filling level and, of course, the sequence of the individual analysis steps.  For the duration of the analysis and the evaluation, all samples currently to be processed should then remain accessible, whereby several hundred samples are ideally underway in the distribution system simultaneously.   Analyses can then be quickly repeated or additional analyses performed and any subsequently necessary assessments undertaken.  Upon completion of the analysis, the samples should be automatically ejected, disposed of following a storage period of a couple of days or, if necessary, transferred to a suitable container for long-term archiving.

Thus, the requirements placed on an automatic sample distribution system are high in terms of capacity, reliability and, most importantly, flexibility.  The distribution system must be able to handle alternating tasks and changes to the workflow.  It must also be easily expandable so that, new or modified analytic devices can be integrated even at a later point in time without considerable effort.  With the development of the lab.sms® fully automatic sample distribution system, GLP Systems has demonstrated that these requirements can be met today.  It transports each sample (specimen) separately, as this is the only way to achieve flexible, custom, and optimum organization of individual samples.  Thus, it differs fundamentally from systems that transport racks with five or ten specimens.

High Flexibility During Sample Transport and Distribution

Samples traveling on "Small trolleys" through the laboratory where speed and reliability are top priorityIn the sample distribution system designed by the Hamburg-based specialists, the identity of the specimen is linked to the identity of the moveable sample carrier upon delivery to the allocation point.  The distribution system therefore knows the sample and knows on which trolley it is currently being transported, as well as which analyses are necessary.  Changes to the sequence can be made retroactively without issues since random access is possible.  For this purpose, the position of the specimen and the assignment to the trolley are checked periodically during transport at identification points.  The trolleys with the specimens then move automatically over plastic rails to the respective analysis stations.  The track switches which they pass over while underway are appropriately set by the primary control system.

Each track switch handles an average of 4,500 sorting processes per hour; 4,500 specimens per hour can be recognized and individually guided in one of two directions.  Since all track switches are able to operate simultaneously, for example, a system with 50 different track switches yields a sorting capacity of 225,000 sorting operations per hour, or more than 60 per second.  This capacity is necessary, since many specimens are in a waiting queue before and after the analysis and thus move over track switches frequently.  The high sorting capacity of the track switches thereby satisfies an important prerequisite for the organizational flexibility in laboratory operation.  Also important for smooth operation are the "small trolleys" on which the samples travel through the laboratory where speed and reliability are top priority.

Compact Drives for Fast, Reliable Sample Transport

The compact trolleys or "specimen taxis,” actually have a very simple design.  Drive, battery, electronics and proximity switch are all integrated, allowing the taxis to very precisely accelerate, decelerate or stop at the analysis stations.  Chosen for the drives were brushless DC-gearmotors.  The motors from the comprehensive FAULHABER product range are designed for high reliability, smooth, cogging-free running properties and a long service life which means they can travel many kilometers in the automatic distribution systems without wear being a concern.  All of this is particularly important as the blood samples are usually transported without a cover. The rare earth magnet of the rotor and the coreless winding also ensure high performance and dynamics in a compact size.

The drives, which deliver approx. 0.3 W and a torque of up to 6 mNm with a diameter of about 15 mm and length of 15 mm, drive the wheel of the "specimen taxi" via a diameter-compliant spur gearhead (reduction 1:10) at Track switch handles an average of 4,500 sorting processes per hourthe ideal operating point.  Thanks to their compact dimensions, they could be easily integrated, and their low power requirements were ideally suited to the application as the charging intervals of the batteries are sufficiently long. To ensure that the trolleys are always ready for use, the charge state is constantly monitored by integrated electronics so that they can be recharged before they come to a standstill.  Additionally, the identification number of the "taxi" is stored here which evaluates the signals of the proximity switch.  The motor electronics can appropriately adjust the speed of the brushless DC-motors and even stopping the motor.

The solution has already proven effective in practical use in a large medical laboratory in Hamburg, Germany.  Some 3,000 hematology specimens are processed there daily with 19 online analyzers with additional applications planned.  Modern miniature drives continue to prove their versatility in many industries as it is possible to apply the "specimen taxi" principle to other application areas.  Similar automatic distribution systems are conceivable wherever small parts pass through different production or inspection stations separately.

To learn more about how MICROMO can provide a compact motion solution for your next application, contact us now to speak with a MICROMO engineer.