Automated analyser
Encyclopedia
An automated analyser is a medical laboratory
instrument designed to measure different chemicals and other characteristics in a number of biological samples
quickly, with minimal human assistance.
These measured properties of blood and other fluids may be useful in the diagnosis of disease.
Many methods of introducing samples into the analyser
have been invented. This can involve placing test tube
s of sample into rack
s, which can be moved along a track, or inserting tubes into circular carousels that rotate to make the sample available. Some analysers require samples to be transferred to sample cups. However, the effort to protect the health and safety of laboratory staff has prompted many manufacturers to develop analysers that feature closed tube sampling, preventing workers from direct exposure to samples.,
Samples can be processed singly, in batches, or continuously.
The automation of laboratory testing does not remove the need for human expertise (results must still be evaluated by medical technologist
s and other qualified clinical laboratory professionals), but it does ease concerns about error reduction, staffing concerns, and safety.
or private medical laboratory
. Automation of the testing process has reduced testing time for many analytes from days to minutes. The history of discrete sample analysis for the clinical laboratory began with the introduction of the "Robot Chemist" invented by Hans Baruch
and introduced commercially in 1959[1].
AutoAnalyzer
is an automated analyzer using a special flow technique named "continuous flow analysis (CFA)", invented in 1957 by Leonard Skeggs, PhD and first made by the Technicon Corporation. The first applications were for clinical (medical) analysis. The AutoAnalyzer profoundly changed the character of the chemical testing laboratory by allowing significant increases in the numbers of samples that could be processed. The design based on separating a continuously flowing stream with air bubbles largely reduced slow, clumsy, and error prone manual methods of analysis.
The types of tests required include enzyme
levels (such as many of the liver function tests
), ion levels (e.g. sodium
and potassium
), and other tell-tale chemicals (such as glucose
, serum albumin
, or creatinine
).
Simple ions are often measured with ion selective electrode
s, which let one type of ion through, and measure voltage
differences. Enzymes may be measured by the rate they change one coloured substance to another; in these tests, the results for enzymes are given as an activity, not as a concentration of the enzyme. Other tests use colorimetric changes to determine the concentration of the chemical in question. Turbidity may also be measured.
and other reactions that employ the use of antibody-antigen reactions.
When concentration of these compounds is too low to cause a measurable increase in turbidity
when bound to antibody, more specialised methods must be used.
Recent developments include automation for the immunohaematology
lab, also known as transfusion medicine
.
s, erythrocyte sedimentation rate
s (ESRs), or coagulation
tests.
Electrical analysis involves passing a dilute solution of the blood through an aperture across which an electrical current is flowing. The passage of cells through the current changes the impedance
between the terminals (the Coulter principle
). A lytic reagent is added to the blood solution to selectively lyse the red cells
(RBCs), leaving only white cells
(WBCs), and platelets intact. Then the solution is passed through a second detector. This allows the counts of RBCs, WBCs, and platelets to be obtained. The platelet count is easily separated from the WBC count by the smaller impedance spikes they produce in the detector due to their lower cell volumes.
Optical detection may be utilised to gain a differential count of the populations of white cell types. A dilute suspension of cells is passed through a flow cell, which passes cells one at a time through a capillary tube past a laser
beam. The reflectance, transmission and scattering of light from each cell is analysed by sophisticated software giving a numerical representation of the likely overall distribution of cell populations.
Reticulocyte
counts can now be performed by many analysers, giving an alternative to time-consuming manual counts. Many automated reticulocyte counts, like their manual counterparts, employ the use of a supravital dye such as new methylene blue to stain the red cells containing reticulin
prior to counting. Some analysers have a modular slide maker which is able to both produce a blood film of consistent quality and stain the film, which is then reviewed by a medical laboratory professional.
s, Prothrombin time
s (and the calculated INRs commonly used for therapeutic evaluation), Lupus anticoagulant
screens, D dimer assays, and factor assays.
Coagulometers require blood samples that have been drawn in tubes containing sodium citrate
as an anticoagulant. These are used because the mechanism behind the anticoagulant effect of sodium citrate is reversible. Depending on the test, different substances can be added to the blood plasma to trigger a clotting reaction. The progress of clotting may be monitored optically by measuring the absorbance of a particular wavelength of light by the sample and how it changes over time.
readers, while not strictly analysers, hold a rack of samples for a set period of time, after which the reader determines how far the red cells
have fallen by detecting levels with light beams.
As ESR tests become less popular they are being replaced by plasma viscosity tests. The advantage of this test over ESR is that fewer variables can affect the result, so it can give a more direct impression of the plasma protein content of a sample. Analysers that measure plasma viscosity commonly work by drawing a small sample of plasma through a narrow capillary using a constant pressure and measuring the time taken for the sample to move a
Analysers that fall into this category include instruments that perform:
Medical laboratory
A medical laboratory or clinical laboratory is a laboratory where tests are done on clinical specimens in order to get information about the health of a patient as pertaining to the diagnosis, treatment, and prevention of disease.-Departments:...
instrument designed to measure different chemicals and other characteristics in a number of biological samples
Sample (material)
In general, a sample is a limited quantity of something which is intended to be similar to and represent a larger amount of that thing. The things could be countable objects such as individual items available as units for sale, or a material not countable as individual items. Samples of countable...
quickly, with minimal human assistance.
These measured properties of blood and other fluids may be useful in the diagnosis of disease.
Many methods of introducing samples into the analyser
Analyser
An analyser, also spelt analyzer, is a person or device that analyses given data. It examines in detail the structure of the given data and tries to find patterns and relationships between parts of the data...
have been invented. This can involve placing test tube
Test tube
A test tube, also known as a culture tube or sample tube, is a common piece of laboratory glassware consisting of a finger-like length of glass or clear plastic tubing, open at the top, usually with a rounded U-shaped bottom....
s of sample into rack
Rack
- Kinds of racks :* Amp rack, short for amplifier rack, a piece of furniture in which amplifiers are mounted* Bicycle rack, a frame for storing bicycles when not in use* Breast...
s, which can be moved along a track, or inserting tubes into circular carousels that rotate to make the sample available. Some analysers require samples to be transferred to sample cups. However, the effort to protect the health and safety of laboratory staff has prompted many manufacturers to develop analysers that feature closed tube sampling, preventing workers from direct exposure to samples.,
Samples can be processed singly, in batches, or continuously.
The automation of laboratory testing does not remove the need for human expertise (results must still be evaluated by medical technologist
Medical technologist
A Medical Laboratory Scientist is a healthcare professional who performs chemical, hematological, immunologic, microscopic, and bacteriological diagnostic analyses on body fluids such as blood, urine, sputum, stool, cerebrospinal fluid , peritoneal fluid, pericardial fluid, and synovial...
s and other qualified clinical laboratory professionals), but it does ease concerns about error reduction, staffing concerns, and safety.
Routine biochemistry analysers
These are machines that process a large portion of the samples going into a hospitalHospital
A hospital is a health care institution providing patient treatment by specialized staff and equipment. Hospitals often, but not always, provide for inpatient care or longer-term patient stays....
or private medical laboratory
Medical laboratory
A medical laboratory or clinical laboratory is a laboratory where tests are done on clinical specimens in order to get information about the health of a patient as pertaining to the diagnosis, treatment, and prevention of disease.-Departments:...
. Automation of the testing process has reduced testing time for many analytes from days to minutes. The history of discrete sample analysis for the clinical laboratory began with the introduction of the "Robot Chemist" invented by Hans Baruch
Hans Baruch
Hans Baruch is an American physiologist/inventor who is noted mainly for his contributions to scientific apparatus and instruments in the field of automated clinical chemistry...
and introduced commercially in 1959[1].
AutoAnalyzer
AutoAnalyzer
AutoAnalyzer is an automated analyzer using a special flow technique named "continuous flow analysis " first made by the Technicon Corporation. The instrument was invented 1957 by Leonard Skeggs, PhD and commercialized by Jack Whitehead's Technicon Corporation...
is an automated analyzer using a special flow technique named "continuous flow analysis (CFA)", invented in 1957 by Leonard Skeggs, PhD and first made by the Technicon Corporation. The first applications were for clinical (medical) analysis. The AutoAnalyzer profoundly changed the character of the chemical testing laboratory by allowing significant increases in the numbers of samples that could be processed. The design based on separating a continuously flowing stream with air bubbles largely reduced slow, clumsy, and error prone manual methods of analysis.
The types of tests required include enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
levels (such as many of the liver function tests
Liver function tests
Liver function tests , are groups of clinical biochemistry laboratory blood assays designed to give information about the state of a patient's liver. The parameters measured include PT/INR, aPTT, albumin, billirubin and others...
), ion levels (e.g. sodium
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
and potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
), and other tell-tale chemicals (such as glucose
Blood sugar
The blood sugar concentration or blood glucose level is the amount of glucose present in the blood of a human or animal. Normally in mammals, the body maintains the blood glucose level at a reference range between about 3.6 and 5.8 mM , or 64.8 and 104.4 mg/dL...
, serum albumin
Serum albumin
Serum albumin, often referred to simply as albumin is a protein that in humans is encoded by the ALB gene.Serum albumin is the most abundant plasma protein in mammals. Albumin is essential for maintaining the osmotic pressure needed for proper distribution of body fluids between intravascular...
, or creatinine
Creatinine
Creatinine is a break-down product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body...
).
Simple ions are often measured with ion selective electrode
Ion selective electrode
An ion-selective electrode , also known as a specific ion electrode , is a transducer that converts the activity of a specific ion dissolved in a solution into an electrical potential, which can be measured by a voltmeter or pH meter. The voltage is theoretically dependent on the logarithm of the...
s, which let one type of ion through, and measure voltage
Voltage
Voltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...
differences. Enzymes may be measured by the rate they change one coloured substance to another; in these tests, the results for enzymes are given as an activity, not as a concentration of the enzyme. Other tests use colorimetric changes to determine the concentration of the chemical in question. Turbidity may also be measured.
Immuno-based analysers
Antibodies are used by some analysers to detect many substances by immunoassayImmunoassay
An immunoassay is a biochemical test that measures the presence or concentration of a substance in solutions that frequently contain a complex mixture of substances. Analytes in biological liquids such as serum or urine are frequently assayed using immunoassay methods...
and other reactions that employ the use of antibody-antigen reactions.
When concentration of these compounds is too low to cause a measurable increase in turbidity
Turbidity
Turbidity is the cloudiness or haziness of a fluid caused by individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality....
when bound to antibody, more specialised methods must be used.
Recent developments include automation for the immunohaematology
Immunohaematology
Immunohematology, more commonly known as blood banking is a branch of hematology which studies antigen-antibody reactions and analogous phenomena as they relate to the pathogenesis and clinical manifestations of blood disorders. A person employed in this field is referred to as an immunohematologist...
lab, also known as transfusion medicine
Transfusion medicine
Transfusion medicine is the branch of medicine that is concerned with the transfusion of blood and blood components. The blood bank is the section of the clinical laboratory where medical technologists process and distribute blood products under the supervision of a medical director, often...
.
Haematology analysers
These are used to perform complete blood countComplete blood count
A complete blood count , also known as full blood count or full blood exam or blood panel, is a test panel requested by a doctor or other medical professional that gives information about the cells in a patient's blood...
s, erythrocyte sedimentation rate
Erythrocyte sedimentation rate
The erythrocyte sedimentation rate , also called a sedimentation rate or Biernacki Reaction, is the rate at which red blood cells sediment in a period of 1 hour...
s (ESRs), or coagulation
Coagulation
Coagulation is a complex process by which blood forms clots. It is an important part of hemostasis, the cessation of blood loss from a damaged vessel, wherein a damaged blood vessel wall is covered by a platelet and fibrin-containing clot to stop bleeding and begin repair of the damaged vessel...
tests.
Cell counters
Automated cell counters sample the blood, and quantify, classify, and describe cell populations using both electrical and optical techniques.Electrical analysis involves passing a dilute solution of the blood through an aperture across which an electrical current is flowing. The passage of cells through the current changes the impedance
Electrical impedance
Electrical impedance, or simply impedance, is the measure of the opposition that an electrical circuit presents to the passage of a current when a voltage is applied. In quantitative terms, it is the complex ratio of the voltage to the current in an alternating current circuit...
between the terminals (the Coulter principle
Coulter principle
The term “Coulter Principle” refers to the use of an electric field for counting and sizing dilute suspensions of particles in conducting liquids. The phrase was coined when Wallace H. Coulter was awarded US Patent #2,656,508, Means for Counting Particles Suspended in a Fluid...
). A lytic reagent is added to the blood solution to selectively lyse the red cells
Red blood cell
Red blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...
(RBCs), leaving only white cells
White blood cell
White blood cells, or leukocytes , are cells of the immune system involved in defending the body against both infectious disease and foreign materials. Five different and diverse types of leukocytes exist, but they are all produced and derived from a multipotent cell in the bone marrow known as a...
(WBCs), and platelets intact. Then the solution is passed through a second detector. This allows the counts of RBCs, WBCs, and platelets to be obtained. The platelet count is easily separated from the WBC count by the smaller impedance spikes they produce in the detector due to their lower cell volumes.
Optical detection may be utilised to gain a differential count of the populations of white cell types. A dilute suspension of cells is passed through a flow cell, which passes cells one at a time through a capillary tube past a laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...
beam. The reflectance, transmission and scattering of light from each cell is analysed by sophisticated software giving a numerical representation of the likely overall distribution of cell populations.
Reticulocyte
Reticulocyte
Reticulocytes are immature red blood cells, typically composing about 1% of the red cells in the human body.Reticulocytes develop and mature in the red bone marrow and then circulate for about a day in the blood stream before developing into mature red blood cells. Like mature red blood cells,...
counts can now be performed by many analysers, giving an alternative to time-consuming manual counts. Many automated reticulocyte counts, like their manual counterparts, employ the use of a supravital dye such as new methylene blue to stain the red cells containing reticulin
Reticular fiber
Reticular fibers or reticulin is a histological term used to describe a type of fiber in connective tissue composed of type III collagen. Reticular fibers crosslink to form a fine meshwork...
prior to counting. Some analysers have a modular slide maker which is able to both produce a blood film of consistent quality and stain the film, which is then reviewed by a medical laboratory professional.
Coagulometers
Automated coagulation machines or Coagulometers measure the ability of blood to clot by performing any of several types of tests including Partial thromboplastin timePartial thromboplastin time
The partial thromboplastin time or activated partial thromboplastin time is a performance indicator measuring the efficacy of both the "intrinsic" and the common coagulation pathways...
s, Prothrombin time
Prothrombin time
The prothrombin time and its derived measures of prothrombin ratio and international normalized ratio are measures of the extrinsic pathway of coagulation. This test is also called "ProTime INR" and "INR PT". They are used to determine the clotting tendency of blood, in the measure of warfarin...
s (and the calculated INRs commonly used for therapeutic evaluation), Lupus anticoagulant
Lupus anticoagulant
Lupus anticoagulant is an immunoglobulin that binds to phospholipids and proteins associated with the cell membrane. It is important to note that this disease name is actually a misnomer...
screens, D dimer assays, and factor assays.
Coagulometers require blood samples that have been drawn in tubes containing sodium citrate
Sodium citrate
Trisodium citrate has the chemical formula of Na3C6H5O7. It is sometimes referred to simply as sodium citrate, though sodium citrate can refer to any of the three sodium salts of citric acid. It possesses a saline, mildly tart flavor. For this reason, citrates of certain alkaline and alkaline earth...
as an anticoagulant. These are used because the mechanism behind the anticoagulant effect of sodium citrate is reversible. Depending on the test, different substances can be added to the blood plasma to trigger a clotting reaction. The progress of clotting may be monitored optically by measuring the absorbance of a particular wavelength of light by the sample and how it changes over time.
Other haematology apparatus
Automatic ESRErythrocyte sedimentation rate
The erythrocyte sedimentation rate , also called a sedimentation rate or Biernacki Reaction, is the rate at which red blood cells sediment in a period of 1 hour...
readers, while not strictly analysers, hold a rack of samples for a set period of time, after which the reader determines how far the red cells
Red blood cell
Red blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...
have fallen by detecting levels with light beams.
As ESR tests become less popular they are being replaced by plasma viscosity tests. The advantage of this test over ESR is that fewer variables can affect the result, so it can give a more direct impression of the plasma protein content of a sample. Analysers that measure plasma viscosity commonly work by drawing a small sample of plasma through a narrow capillary using a constant pressure and measuring the time taken for the sample to move a
Miscellaneous Analysers
Some tests and test categories are unique in their mechanism or scope, and require a separate analyser for only a few tests, or even for only one test. Other tests are esoteric in nature—they are performed less frequently than other tests, and are generally more expensive and time-consuming to perform. Even so, the current shortage of qualified clinical laboratory professionals has spurred manufacturers to develop automated systems for even these rarely performed tests.Analysers that fall into this category include instruments that perform:
- DNADNADeoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
labeling and detection - Osmolarity and osmolality measurement
- Measurement of Glycosylated haemoglobinGlycosylated hemoglobinGlycated hemoglobin is a form of hemoglobin that is measured primarily to identify the average plasma glucose concentration over prolonged periods of time. It is formed in a non-enzymatic glycation pathway by hemoglobin's exposure to plasma glucose...
(Haemoglobin A1C), and - Aliquotting and routing of samples throughout the laboratory