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In unit test systems, the volume of reagent has been pre-measured. The ‘dose’ of reagent,
already in the reaction vessel, needs only to be delivered to the area where the sample will be
added. This is usually done mechanically by pushing the reaction container to the sampling
station or loading zone.
In continuous ow systems, peristaltic pumps and plastic tubing transport the specimen
and reagent through the system. The volume of reagent is determined by the inside diameter
of the rubbing, just as the volume of sample is determined. As the samples ow continuously
through the tubing, reagents are added at dierent points, reaction conditions are provided
around the tubing, and timing is determined by the distance of the coil to travel through the
reaction chamber.
Positive displacement syringes are another method to deliver specic volumes of reagent
to a reaction chamber. These syringes operate in the same manner as the positive displacement syringes used for sample aspiration and delivery. The speed of the driving motor should
be controlled as closely as possible to prevent sudden changes in velocity and the accuracy
should be veried.
Medical Laboratory Technology: Volume 3
Reagent Handling
Most chemical reactions require the combining of the reagent and sample in exact amounts.
This is called proportioning. In continuous ow analysis, the diameter of the tube regulates
the volume of the reagent uid picked up; for the amount of specimen, the dwelling time of
the probe inside the specimen container determines the amount of specimen picked up. The
rate of ow for all uids is the same. A single peristaltic pump is used for drawing the uids.
For the discrete system, a single probe may measure the volumes of specimens and reagents
but the dwelling time in them varies. Individual automatic dispensers are also used in, some
discrete systems where syringes and volumetric overow devices are used to dispense
requisite quantities of sample and reagent into test tubes or containers. A single-reagent assay
is ideal for automated biochemical analyses. This, however, is not possible and single-reagent
assay is not as accurate.
Reagents can be dispensed directly from bulk containers supplied by the manufacturer, or
reconstituted in the laboratory. Reagents prepared by the manufacturer are expensive and
under the conditions of most developing countries with transportation diculties and cold
storage problems, the preparation of reagents in the laboratory becomes a necessity. Hence
those manufacturers, who are able to supply dry reagents or provide the necessary formula
for the preparation of reagents within the laboratory, will be most successful in marketing
their goods in the developing countries.
Specimen carry-over is a common problem in continuous ow analysis. Thus, if a lowconcentration specimen follows a high-concentration specimen, the former will have carryover eects due to contamination. Either in such a case the specimen should be re-run or
water blank introduced to ush out the system. Alternatively, increase the wash time between
specimens.
Reaction Conditions
Mixing of reagents with the specimen is a vital component of biochemical analysis. This is
accomplished in several ways in the automated systems. In the continuous ow, it is done
through glass coils where the liquid rotates and the liquids (specimen and reagents) fall
through one another during their rise and fall through the loop. In the discrete systems, other
methods are adopted—vibration, slewing action, centrifugal rotation (in centrifugal analysers), pressing and releasing of plastic bags which receive the uids and ultrasonic waves.
Automated incubation is merely a delay station where the test mixture is allowed to react.
The chamber where the incubation is held is heated to the desired temperature by the use of a
heating block, air, water bath or oil bath. Time is a denite limitation. To sustain the advantage
of speedy multiple analyses, the reaction is not taken to completion, as is required in the
manual procedures. Rather, the rate of the reaction can be measured and the values aer the
Automation in Clinical Biochemistry
completion of the reaction are extrapolated. The instrument may also delay the measurement
for a pre-determined length of time or present the reaction mixtures for measurement at
constant intervals of time. In case of continuous ow analysis, all measurements are made
against a standard and as the procedures are precisely timed, the result of the standard is highly
reproducible even if the measurement is made much before the completion of the reaction. In
the discrete system, there are a number of delay stations before the readings are taken.
Dry slide methods accomplish mixing of the sample with premixed, pre-measured reagents through diusion. As the sample comes into contact with the top layer of the slide, it
is drawn by capillary action into the porous layer. As the reagents hydrate, components of
interest diuse into the reagent layers.
Discrete system mix reaction components by means of stirring paddles of sticks, motion
of the reaction vessel, forceful addition of reagents and agitation by air bubbles or ultrasonic
waves. Some system use magnetic stir bars.
Mention should be made of the use of ion-selective electrodes for the measurement of
sodium, potassium, chloride and occasionally carbon dioxide. The reagent handling systems
and reaction conditions for ion-selective electrodes are typically separate from those previous
described with colorimetry or enzymatic measurement. Most ion-selective electrodes are
of the ow-through variety in which the sample and reference solutions are moved via
peristaltic pumps through chambers containing xed indicator and reference electrodes.
The specimen must remain in contact with the electrodes long enough to reach steady state.
The electrodes are designed to minimize response time so that a steady state can be reached
rapidly, maximizing the throughput of the system.
967
Reaction Measurement
Aer the reaction is completed, there must be a sensing device to measure the change
like development of colour. Traditionally, absorbance photometry has been used for the
measurement of analytes. This method has three basic components—light source, spectral
isolation and a detector. Light sources commonly include tungsten, quartz-halogen,
deuterium, mercury and xenon lamps. Each has advantages and disadvantages. Interference
lters, monochromators, such as diraction gratings help in spectral isolation. Diraction
gratings provide a continuous spectrum and therefore a great choice of wavelengths for use.
A diraction grating also allows the use of two or more wavelengths (bichromatics) at the
same time for correction purposes, to eliminate the absorbance contribution of interfering
substances. Photomultiplier tubes (PMTs) are the most prevalent detectors in automated
systems. They are sensitive and give a very rapid response.
In recent years, methods other than absorbance photometry have been developed for the
measurement of analytes. Reectance photometry is one of them. In reectance photometry,
diuse, reected light rather than absorbed light is measured. This is used in many equipment that employ ‘dry chemistry’. One drawback to reectance photometry is that intensities
are not linear with concentration of the analytes of interest; they do not follow Beer’s law.
To correct for this deviation, mathematical algorithms are used to linearize the relationship
between the intensity and reected light and the analyte concentration. Other photometric
methods include turbidimetry, nephelometry and uorometry. Many of these techniques are
used in automated immunoassays.
The sensing can be done on the original site where the reaction occurred (internal) or taken
into another vessel (external) to make the measurements. In the continuous ow analysis,
the reagent stream under analysis ows continuously through the ow cell which acts like
a cuvee. The air bubbles are removed by the de-bubbler before the reacted solution enters
the ow cell for photometric measurements. The sensing device converts the optical response
into electrical impulses which are then sent to the read out device. The read out device can be
the strip chart on which the results are traced or on the digital display.
Chemical reactions can be monitored either at one time point or at many. Commonly, single-
point monitoring is used for end-point (or midpoint) analysis in which the reaction has gone
968
to completion or the instrument extrapolates the value, as mentioned earlier. Multiple-point
monitoring is done in case of kinetic studies (enzyme activity).
Medical Laboratory Technology: Volume 3
Calculation of Results
In the automated system, the results are automatically computed from the response of the
sensor and nally printed out in appropriate units. The printing can be done directly on
the patient’s request slip (or reporting slip) or on the laboratory form. In order to avoid
transcription errors, it is advisable that multiple copies of the print out should be made so
that dierent copies of the same report can be routed to dierent destinations—nancial
oce, physician, patient’s record, laboratory record and others.
QuaLIty controL and PreventIve maIntenance
Automated systems are not free from errors. In fact, they frequently render a false sense
of security among the users and the results may be far from reliable. The system must be
frequently subjected to QC procedures using control sera. Control runs should be done in the
beginning of each day and the results ploed on the QC chart (Chapter 7 of Vol. 1).
Preventive maintenance is done to ensure the analyser continues to function properly.
Keeping an analyser clean may be the most important maintenance procedure, regardless
of the instrument. Cleaning up spilled specimens and reagents will help prevent future
malfunctions. Other maintenance procedures include discarding waste, cleaning water baths,
cleaning reaction vessels (if reusable), replacing reagents, replacing worn or damaged parts
(e.g., lters, rubbing syringes, probes and lamps), and readjusting components to ensure
proper functioning.
automated 'stat' testIng
The word ‘stat’ is an abbreviation of the Latin word statin, meaning immediately. Many
clinical conditions require immediate reporting of results. If the automated system cannot
be adapted towards such a condition of changing the priorities, it will be a handicap. In
some systems, such as the continuous ow analysis, the interruption in the processing of the
current samples and the time required to change to the proper reagents may not be acceptable
or practical. In such cases discrete analysers are handy. The other requirement for automated
stat procedures is to have a short dwell time. The machine may not have a high throughput.
Throughput is an expression that indicates the maximum number of individual samples or
test analyses that can be practically performed per hour by an assay system with the required
dwell time taken into account.
comPuters In cLInIcaL LaboratorIes
Computing and use of computers has become pervasive in our society. With commoditization
of personal computers, and availability of broad spectrum of soware applications, computers
are used in every scientic eld, including the eld of laboratory medicine. The era of
computerization has eectively driven high levels of QC, while increasing the laboratory
output, and expediting the eectiveness of diagnosis.
Computer application in the clinical laboratory can be classied into ve groups:
1. Specimen handling: Identication and recording
2. Operation of instruments: Automatic and semiautomatic
Automation in Clinical Biochemistry
969
3. Storage of information: Results of laboratory ndings
4. Communication: Facilitates information transfers between laboratories and the physi-
cian
5. Robotics: Robot-driven automation (commonly referred to as robotics), further stream-
lines the processes in clinical laboratories. Robotics is applied in two ways: to reduce the
risk of humans in handling contaminated samples, as well as to achieve higher level of
precision
Computer systems have many denite advantages over other laboratory management
systems. Not only they are capable of processing vast amounts of data with higher accuracy;
they are also able to store and retrieve information in real-time, thus making the end-to-end
performance evaluation (QC) of laboratory instruments with new degrees of eciency.
Computers have become a pervasive part of the human society. The usage and applications
of computers and computer-assisted systems have proliferated across the advanced nations
as well as third world countries. Given the widespread application of computers, it is desirable to understand WHAT types of computers exist and HOW basics of computers work.
A computer in its simplest term is expressed as a machine that manipulates data accord-
ing to a list of instructions. The ability to store and execute instructions called programs
makes computers extremely versatile and distinguishes them from calculators. The heart of a
computer is its central processing unit (CPU), which is essentially a sophisticated integrated
circuit, which enables it to carry out arithmetic functions, logic functions and to move data in
and out of memory. Memories are of two types: one is referred to as random-access-memory
or RAM, which is programmable and erasable, and the other is called read-only-memory or
ROM, which normally cannot be modied. This part of the memory allows the computer, in
conjunction with the CPU, to function independently of human input, a feature that allows
for almost complete automation in the laboratory, which is the focus of this chapter.
The aforementioned parts of the computer, along with a variety of input devices (such
as keyboard, mouse, scanner or a tablet) have become a very useful tool in the laboratory.
Although it may not be obvious at times, several automated laboratory instruments have
incorporated these devices into their designs in a pervasive way. Add to it, a variety of
output devices (such as screen, printer, ploer or speaker), which has made data retrieval
very simple. Via this modernization of technology, every laboratory has beneted in terms of
eectiveness and eciency.
Computers come in many dierent sizes and complexity depending on their use.
1. Supercomputers and mainframes are the most powerful machines, and tend to have no
use in the average clinical laboratory seing. These machines are equivalent of multiple
high performance computers working in parallel as a single system.
2. Servers are computers that have been optimized to provide services to other computers
over a network. Servers usually have powerful processors, lots of memory and large
hard drives. This class of machines used to be referred to as mini-computers.
3. Workstations are high-end desktop computers that typically have powerful processor,
and enhanced capabilities for performing a special group of task, such as 3D graphics
or game development.
4. Desktops or personal computers are the most common and widely used, and have
proliferated in oce and laboratories due to their small portable size and versatility.
The personal computer denes a computer designed for general use by a single person.
While a Mac is a PC, most people relate the term with systems that run the Windows
operating system. PCs were rst known as microcomputers because they were a complete
computer but built on a smaller scale than the huge systems in use by most businesses.
A PC that is not designed for portability is a desktop computer. The expectations with
desktop systems are that you will set the computer up in a permanent location.
5. Laptops or Notebooks are portable computers that integrate the display, keyboard, a
pointing device or trackball, processor, memory and hard drive all in a baery-operated
package slightly larger than an average hardcover book.
970
6. Handhelds are palm-top computers (commonly called Personal Digital Assistants or
PDAs) are tightly integrated computers that oen use ash memory instead of a hard
drive for storage. These computers usually do not have keyboards but rely on touchscreen technology for user input. PDAs are typically smaller than a paperback book,
very lightweight with a reasonable baery life.
7. Wearables are ultraportable computers that can be integrated into watches, cell phones,
visors and clothing. This class of computers support common consumer applications
such as email, camera, database, multimedia, calendar and phonebook.
Medical Laboratory Technology: Volume 3
Challenges of Computerization
Automation and computerization are enablers for eciency and eectiveness. However,
the steps of computerization in the laboratory are not necessarily a panacea. As with all
machineries, the computer is subject to upkeep and breakdown. Environmental conditions
can adversely aect the computer and its peripheral equipment. Excessive heat, humidity,
dust, magnetic elds, smoke and transient loss or changes (even minor) in electrical line
currents, can cause adverse results, such as data loss or data corruption. Therefore, wherever
computers are deployed, it is imperative that:
• Electrical voltage stabilization is provided, with preferably uninterrupted power supply
(UPS) backup units.
• Backup copies of all data (raw or otherwise) are kept in an o-line storage so that the
information is intact and the data can be re-created in the event of a problem.
• Automated procedures can be bypassed manually or alternative procedures be made
available in the laboratory, particularly those procedures which are vital in the emergency situation. In cases where electricity is a frequently interrupted, supplemental unit
such as voltage stabilizer, baery backup (UPS unit) or inverter is essential, depending
on the extent of power uctuation and/or the duration of power loss. A typical UPS unit
usually keeps the computer running until data gets saved to the desk and the computer
has had a chance to shut itself down gracefully.
• In developing countries, a fully redundant computer system that can function as a back-
up is desirable due to the frequent scarcity of technical labour to expedite the repair of
the primary computer in the event of a failure.
In the following section, an aempt has been made to provide a primer to orient the reader’s
general understanding of computers. The concepts include hardware, soware, interfacing,
storage, input, output and computer compatibility.
Glossary of Terms
Before beginning the discussion of the computer, familiarization with some of the terms
commonly used in computer technology is necessary:
Address: The physical location of a piece of information within the computer’s memory.
Algorithm: The series of operations required to do a simple task. For example, algorithm
might be set up to calculate the mean from a list of numbers.
Binary code: It is a numeration system having a base of 2. It has only 0's and l's (or 'ON' and
'OFF' switches), which are expressed in powers of the number 2. The word 'bit' evolved from
binary digit which happens to be the computer’s smallest unit of data representation. A bit is
like a toggle switch, which can have only two possible states, either ‘on’ or ‘o’.
Booting: The process of starting a program of the computer aer it has been turned o. It is
derived from the phrase ‘pulling oneself up by one’s bootstraps’.
Browser: An ‘easy to use’ standard user interface which is the most popular way to interact
(or browse) with the interconnected computers on the Internet.
Automation in Clinical Biochemistry
971
Bug: An error or problem in the code of a program. It can be a logical or a typographical error.
Byte: A set of 8 bits makes a ‘byte’ that represents a character to the digital computer (e.g., one
alphabetical or numerical character is represented by a byte).
Code: The set of instructions wrien to perform a task in the computer. A code may be wrien
in any language compatible with the computer.
CD: Compact Disc or CD is a low-cost analogue optical storage medium that has essentially
replaced the oppy disk. There is a variety of CD-s available, depending on user’s need. Some
common variations of CD (also called CD-ROM) are, write-once audio and data storage CDR, rewritable media CD-RW, Super Audio CD (SACD), Video Compact Discs (VCD), Photo
CD, Picture CD and Enhanced CD. Of these media types, CD-ROMs and CD-Rs remain widely used technologies in the computer industry.
Database: This is the le or series of les in which all the data of a project are stored. From
the database other les can be made to suit various applications and produce various reports.
Directory: The index of le names and locations in a data-storage device such as a disk;
it corresponds to the contents of a book.
Disk: An internal or external device that stores data.
DSL: It is a data communications technology that enables faster data transmission over cop-
per telephone lines than a conventional voiceband modem can provide. It does this by utilizing frequencies that are not used by a voice telephone call. The acronym DSL or xDSL, stands
for Digital Subscriber Line.
DVD: Digital Video Disc or DVD is a low-cost digital optical storage medium that has essentially replaced the oppy disk and CD-s. There is a variety of DVD-s available, depending
on user’s need. Variations of the term DVD oen describe the way data is stored on the discs:
DVD-ROM (Read Only Memory), has data that can only be read and not wrien, DVD-R and
DVD+R can record data only once and then function as a DVD-ROM. DVD-RW, DVD+RW
and DVD-RAM can both record and erase data multiple times.
File: A set of data blocks, which corresponds to a chapter in a book. In a laboratory computer,
there might be a le of all the tests oered by the laboratory along with their names, costs and
reference ranges.
Disk: A device that stress the computer data. It may be internal or external to the computer.
Also, it may be removable or xed, depending on how it is hooked up. Popular storage devices are USB drives, Media Cards and portable drives, which have replaced the oppy drives
in the last decade.
Hardware: This is a general term for the physical equipment used in a computer system.
Hardware includes the CPU, the monitor, keyboard, mouse, printer, etc.
HTML: HTML or Hyper Text Markup Language is the predominant mark-up language
for web pages. It provides a means to describe the structure of text-based information in a
document and to supplement that text with interactive forms and embedded images. HTML
is wrien in the form of tags, surrounded by angle brackets.
Instruction: Commands given to the computer that specify a set of operations that the
computer has to do.
Interface: The connection between dierent components of a computer system or between
dierent computers.
Internet: A global network of interconnected computers worldwide, linked via a variety of
connections, which may be via modem, cable, ADSL or satellite link.
972
Medical Laboratory Technology: Volume 3
I/O: Acronym for Input/Output
Magnetic tape: A data storage medium which closely resembles the tape used to record
music. These devices used as low-cost, high-capacity storage medium for data, but have been
phased out given the advent of new modern technology.
Memory: The part of a computer system which stores data and programs for use by the
computer.
Microcomputer: A computer who’s CPU is a microprocessor. It is usually a desk top or
portable machine having a substantial amount of memory, and a limited number of I/O ports
or peripherals.
Microchip: A semiconductor device with the property to hold transient or permanent data.
It has extensive use in electronic industries. Integrated electronic circuits are embedded on
silicon wafers to construct these microchips.
Microprocessor: A processing unit built in a single silicon chip. They are used to control and
execute tasks involved in the operation of electrical equipment.
Modem: An acronym for modulator-demodulator. It is a device used for communication
facilitation connecting two computers or computer systems through a telephone line. Modems
have become less common, given the advent of the Internet and ‘on-line’ systems.
Program: A set of step-by-step instructions designed to perform designated tasks on a
computer.
RAM (random-access memory): Memory to which one can both read and write, changing the
contents many times during processing. RAM is used to store data temporarily in the sense
that these data are retained only as long as the power is on (refer ROM).
Random access: The ability to have access to a piece of information from an array without
having to look at all the elements from the beginning. An example of random access is the
ability to play a particular selection on a phonograph record without having to play all the
record up to that point.
ROM (read only memory): Storage whose contents cannot be changed by stored program
instructions; it generally contains non-alterable programs and built-in functions of the
computer (see RAM).
Soware: The generic name for the programs, routines and the operational procedures for
computers.
Monitor: The most common display device for computers. It usually consists of a keyboard
and mouse that helps interact with the computer.
USB: Universal Serial Bus is a serial bus and I/O standard to connect devices to a host
computer. It was designed to allow several peripherals to be connected using a single
standardized interface socket and to improve plug and play capabilities of multifarious
computer peripherals such as mouse, keyboards, PDAs, gamepads, joysticks, scanners,
digital cameras, printers, ash drives and external hard drives.
Word: Group of bits which the computer processes at a time. The size of a word ranges from
8–64 bits and is dened by the hardware and soware used in any particular system.
World Wide Web: A ‘web’ or network of networks, which links millions of computers
together, and allows the user to interact with the information via an ‘easy to use’ standardized
universal user interface, called the ‘browser’.
XML: XML or eXtensible Markup Language is a general-purpose specication for creating
custom markup languages, and its most common purpose is to aid information systems in
sharing structured data, primarily over the Internet.
Automation in Clinical Biochemistry
973
Operation of a Computer
A computer is made operational by combination of two major components—the hardware
and the soware.
Hardware
The hardware is the physical structure of the computer which has three major components—
CPU, Input/Output and Memory, as outlined in form of a conceptual view of the computer
in Figure 32.1.
Figure 32.1 Conceptual view of primary parts of a computer
Central processing unit This unit coordinates and directs all the operations of a computer
system. The CPU has two components, the arithmetic-logic unit (ALU) that performs numerical computations, and the control unit (CU) that regulates the timing and coordination of
machine activities.
Physically, the CPU is a unit of electronic circuitry (integrated circuit). Miniaturization of
technology has made large-scale integrated circuits t in tiny footprint, thus shrinking the
size of the CPU. A computer can have a single or multiple CPUs, which functions as a cluster,
and supervises the operations within the computer. The other components such as ROM and
RAM are under the control and governance of the CPU.
When a soware program is executed, it is the CPU that orchestrates its execution by
performing the operations specied by the encoded instructions (Figure 32.2). When a
mathematical calculation is involved the ALU is activated; if storage of data in memory or
secondary storage is required, the CPU sets up and supervises the storage of data. If a printout
of data is called for by the programs, the printer is activated and the data from the memory is
passed through the CPU and transmied to the printer. The connectors which indirectly link
the CPU with its peripherals are referred to as the interface cards. In summary, the CPU is the
brain and ‘command centre’ of the computer.
Figure 32.2 Components and primary parts of a computer
974
Input/Output (I/O) This interface unit transfers information into and out of the computer.
It may include a monitor, keyboard, mouse, scanner, printer, bar-code reader, speaker or a
laboratory instrument. Some of the common components of the computer are shown in
Figure 32.2.
Memory/storage unit The memory unit stores data for use by the computer. There are two
kinds of storage units—the primary storage unit and the secondary storage unit. The primary
storage unit is built into the computer system. Part of primary storage contains permanent
information, which never gets erased or altered. This is called ROM. It contains pre-dened
tasks or perhaps a built in computer language. The other part is called RAM. This is designed
to contain temporary information and is addressable and erasable. It may contain the user’s
computer program, program data and its computed results.
Secondary storage units (also called external memory) can be thought of as being ‘acces-
sory’. Its usage is not indispensable for a computer. Disk drives, tape drives or removable
media are some of the most widely used secondary storage units. Their purpose is to expand
the memory and to store data for later usage, accessing the data as needed by the program.
Conceptually, the memory is a large array of electronic circuits. Each individual circuit may
be switched ‘on’ (coded as 1) or ‘o’ (coded as 0). As long as there is an electric current, the
condition of being on or o codes the memory with bits of data. The ability to manipulate
data in the form of an on/o code is the fundamental task of the digital computer’s CPU.
The on/o property of microchips makes them binary machines. As a result, many coding
aributes are in powers of 2. The simplest memory element, the on/o (I/O) condition, is
termed a bit and groups of 8 bits are called bytes. Memory is generally expressed in terms of
megabytes (MB), which is approximately a million bytes. A single character, like the leer ‘A’,
takes up 1 byte (or 8 bits) of memory. It follows that in one line of 80 characters, 80 bytes will
be required. (Note Each space should also be considered as a character).
The discussion of computer memory would be incomplete without mentioning two
terms—the address and the content. In order to logically store data in the computer’s memory,
data must be placed in an orderly way into locations within the computer’s memory array.
The location of the data within the array is called the address and the information stored
at the address is referred to as content. The content may be determined by addressing the
memory location. A programmer prepares the program (soware) using a suitable computer
or programming language. On booting up the program, the stored codes get converted by
a translating unit into binary language. It then gets loaded into the RAM and the program
is ready for execution. Pre-wrien programs, which are saved on disk, card or tape, can be
re-loaded time and again into RAM.
The laboratory technician need not know anything about the ‘program’ or computer to
accomplish his goals. He only needs to be familiar with the program’s purpose and the user’s
commands.
Medical Laboratory Technology: Volume 3
Software
The programs and routines involved with the operational procedures are broadly referred to
as soware. The computer does not understand the human language. Hence, the instructions
must be interpreted into a language that the computer understands. To facilitate programming,
various computer languages have been developed which resemble the English language. The
process of programming is relatively complex and requires a set of specic skills; rules must
be followed, and the computer must be instructed every step which is to be performed in
order. There are a variety of programming languages, and programmers usually select the
language best suited for the application. The program code wrien is translated into machine
language (binary code) before execution.
The programming task can be simplied through the use of a owchart, which is a symbolic
presentation of the steps required to solve the problem. Typically, the programmer and
laboratory technician collaborate closely in order to achieve the desired results.
Automation in Clinical Biochemistry
975
Computerization of Clinical Laboratory Instruments
Computer applications in laboratory instrumentation are relatively new. The development
of the microprocessor has revolutionized the very concept of analytical chemistry and
instrumentation. In automated systems, the computer controls each step, including identication of specimen, aspiration of specimen and reagents, reading of results aer periodic
time intervals, standardization, collection of data, tallying of information, comparing and
writing to databases, calculation, and output of results. One of the major role of laboratory
computers is to regulate the QC of data. Quality control is a natural application for the
CPU because of the ease with which large amounts of data can be collected and compared,
calculated, interpreted or standardized. In some cases, the computer can be interfaced
directly to a laboratory instrument so that the QC data and patient’s results may be easily
collected and stored in a database for later use. In less sophisticated programs, the computer
can simply compare the patient’s laboratory values to standards with the acceptable range
supplied by the user. If the result is outside this range, it can be identied automatically with
an asterisk or other mark so that the user may choose to reject the run, collect another sample
or notify the physician of the results.
Storage of laboratory information and the easy access to the stored data have proved to be
most helpful in modern laboratory operations, particularly with increased number of tests
available. This has reduced the time and space needed for ling of papers and in addition,
has made it much easier to provide the previous history of the patient’s laboratory ndings.
Machine failure
The computer is a blessing for the modern era as long it is working. Its failure is always
possible and this can paralyse the entire system, if contingency planning is not in place. This
may occur because of failure of electronic components or occasional abuse and misuse by
the users. The components most likely to fail are those that involve mechanical parts, such as
are found in disk drives and printers. If an electronic component does fail, the usual way to
approach repair is to replace the computer circuit boards that might be involved. It is a good
idea to keep spare parts or backup computers, if at all possible. It is equally wise to identify
a source of technical assistance in the event that mechanical or electronic problems cannot be
serviced promptly by the user.
Computer housing
Computer equipment must be kept at a cool temperature (24°C) and at low humidity. The
level of humidity should be low enough so that it is non-condensing but high enough so that
static electricity is not a problem. These environmental problems are likely to appear in the
form of a memory error or a disk read error.
Conclusion
Computerization is an integral part of laboratory automation and operation. As the numbers
of laboratory tests, patients and diagnostic techniques increase, it becomes imperative that
data be processed and managed more eciently and eectively.
Despite the drawbacks noted in this chapter regarding computerization (including computer failure), careful and thoughtful selection of the computer system together with the
identication of specic purposes for utilization of such a system will resolve most, if not
all of the potential problems before they occur. A common obstacle that must be quickly
overcome is fear and apprehension of computers-assisted technology. As explained in this
chapter, the user of the computer need not have any prior knowledge of computers to get
high-quality results, as long as the individual follows instructions.