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Section 8: GLOSSARY


Acceptable Control Range the range of results that indicate adequate performance when analyzing a control sample. The range is shown in the control's product insert.

Accuracy correctness; freedom from error. The accuracy of results can be measured by comparing them to results accepted as correct, or by comparing them with those from another laboratory (this is "relative accuracy").

Additive a chemical added to a blood collection tube, usually in order to prevent the blood from clotting (anticoagulant).

Aerosol a fine mist in which solid or liquid particles are dispersed.

Agar a dried, sticky substance extracted from various red algae and used as a gel in preparing solid culture media.

Agglutination the clumping together of antigen-bearing cells, bacteria, or particles in the presence of specific antibodies. Also called "clumping."

Alert Values These have been called "panic" values. They reflect the points at which a physician needs to be immediately informed because of the clinical seriousness of the result.


Aliquot a small portion of a measured volume of a substance taken representing the whole.


as a sample


Analysis

a specimen.

Analyte Antibody


the laboratory procedure that enables measurement of the amount of an analyte in

the substance or constitute being measured (e.g., glucose, sodium, theophylline).

a substance formed in the body in response to a foreign substance (an antigen) and


that interacts only with that substance.

Anticoagulant a chemical used to prevent blood from clotting.


Antigen

antibodies.


any substance which, injected into an organism, causes the development of


Antiserum a serum that contain antibodies.

ASCP American Society of Clinical Pathologists (largest certifying organization for laboratory professionals.)



Aseptic Assay


free from infection or septic material; sterile.

the measurement of the amount of a constituent in a specimen; a test.


Atlas a book of reference pictures. There are a variety of published hematology, microscopic

urinalysis, and gram stain atlases available.

Autoclave an instrument that sterilizes material by subjecting it to steam under pressure.

Background Counts Dilution and lysing fluid for blood cell counts may have particulate contaminants which would be counted as cells by an automated counter, thus falsely elevating the

different cell counts.

Batch testing when specimens are kept and run all together at a later time.

Bias (inaccuracy) a measure of the departure from accuracy. A numerical difference between the mean of a set of replicate measurements and the true value of the sample.

Biologic Hazards agents that pose some risk of infection to the laboratory staff, janitorial staff that cleans the office, and the public at large through environmental contamination.

Calibrated (of a measuring device, e.g., a pipette) graduated into appropriate units.

Calibration the process by which readings obtained from an instrument or other measuring device are related to known concentrations of an analyte.

Calibrator a material, solution, or freeze-dried preparation used in calibration. The concentration of the analytes in a calibrator is known to be within a particular range. Calibrators may be a primary or a secondary standard.

Capillarity (capillary action) the attraction between a liquid and a solid that causes the liquid to rise, as for example, into a capillary tube.

Capillary any one of the small vessels that form a network throughout the body for the interchange of substances between the blood and tissue fluid.

Cellular Morphology cells and organisms have certain shapes and configurations which are characteristic and which permit their identification.

Centrifuge an instrument that separates the lighter portions of a solution, mixture, or suspension from the heavier portions by centrifugal force.


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Clean Catch Midstream This is a type of urine specimen collection which minimizes contamination by cleaning off the urethral are washing out of the urethra with urine, stopping

the flow, and then restarting it.


CLIA '88'

laboratories.)


Clinical Laboratory Improvement Act of 1988 (Federal standards for all



Clinical Laboratory

benefit of human patients.

CO2 Rich Atmosphere


a facility that performs tests or investigative procedures for the

Some organisms, most commonly Neisseria species, have complex


growth requirements, including an atmosphere rich in carbon dioxide (5%-10%).

Coagulation the process by which various coagulation factors in the blood interact to form a clot.

Coefficient of Variation a statistical measure of the ratio of the standard deviation of a series of measurements to the mean of the measurements. Expressed as a percentage, the coefficient of variation (CV) shows the precision of measurements.

COLA Commission of Laboratory Assessment (a private, non-profit accrediting organization for POL's.)

Colorimeter the measurement and analysis of color by comparison with a standard in terms of brightness, hue, or purity.

Contaminant a microorganism, chemical, or other material that makes something impure by contact or mixture with it.

Control a material, solution, lyophilized preparation, or pool of collected serum designed to be used in the process of quality control. The concentration of the analytes of interest in the control material are known within limits ascertained during its preparation, and confirmed in use.

Culture the growing of microorganisms or living tissue cells in special media; the growth of the microorganisms or cells.

Culture Medium a substance or preparation used for the cultivation and growth of

. .

-- Illlcroorgarusms.


Data the numerical or qualitative results of a test from which conclusions are made.

DHHS Department of Health and Human Services.

Diagnostic Test a laboratory test or measurement that helps determine the cause or nature of a disease. Laboratory tests are often called "in vitro diagnostic tests."


Diluent

reagent.

Dilution


the liquid (usually distilled water) used to reconstitute a freeze-dried control or

the mixing of a diluent and calibrator, or control, or patient sample. A serial


dilution is the progressive dilution of a substance in a series of tubes in predetermined ratios.

ELISA enzyme-linked immunosorbent assay; a diagnostic test used to detect either antigens or antibodies in a patient's specimen.

Enzyme a compound produced in a cell and capable of greatly increasing the rate of a chemical reaction.

Erythrocyte a red blood cell, one of the elements in peripheral blood.

Etiologic Agent an agent that causes disease.

Evaluation of Performance Periodically, (at lease once a year), the physician laboratory director should perform a performance appraisal of the laboratory staff.


False Negative (Result)

or constituent in question.

False Positive (Result)

or condition in question.

Full Regulation State


a negative test result for a patient who is positive for the condition

a positive test result for a patient who is negative for the constituent

a state in which the laboratory regulation program includes


provisions for licensure, proficiency testing, quality control, personnel requirements, and inspection.

Glycolysis the lowering of glucose concentration in a blood sample by the action of enzymes

in the red blood cells.

Gravimetry the measurement of a substance by determining its weight or specific gravity.

HCFA Health Care Financing Administration.


Hematoma a mass of blood, usually clotted, under the skin in an organ, space, or tissue caused by a break in the wall of a blood vessel.

Hematocrit (also called packed cell volume) the volume percentage of erythrocytes red blood cells) in whole blood.

Hemolysis (adjective hemolytic) the breakdown of red blood cells in serum of plasma, freeing the hemoglobin from the cells. When this happens, the serum or plasma becomes reddish. Hemolysis interferes with some laboratory tests. Beta hemolysis is the production of a clear zone surrounding a bacterial colony on blood agar medium, which is characteristic of certain pathogenic bacteria such as Group A Streptococcus.

Hospital Laboratory a clinical laboratory that is accountable administratively to the hospital's central management and medically to its organized medical staff. Most hospital laboratories are physically located in hospitals but co-location is not required.

lcterus (adjective icteric) a condition in which there is too much bilirubin in the blood; jaundice. An icteric serum sample looks dark yellow ( it may even look greenish). An icteric

- sample may produce erroneous test results.

Immunoassay a diagnostic test that uses a specific antibody or antigen to detect the presence of an analyte.

Inaccuracy see Bias.

In control term used to describe the testing procedure when the results from a control sample or series of control samples are within the acceptable control range.


Infectious Agent

infection.


any microorganism that can invade body tissue and multiply, causing


Incubation the development of microorganisms in a medium. See the Culture Procedures chapter in the guidelines.

Independent Laboratory a clinical laboratory that is independent of all other providers of direct patient care.


Inoculation implanting microorganismsor other substances into a culture medium to allow them to grow. The microorganism or substance implanted is the inoculum.

Inspection an on-site visit to the laboratory by state program inspectors to determine whether the facility is complying with laboratory program requirements.

In Vitro a Latin term, meaning "in glass," used to describe diagnostic tests, which analyze process that occur inside the body (in vivo) from samples of body fluids in glass (test tubes) or other controlled artificial environments.

Instrument Maintenance

Program Manufacturers usually will list suggested preventative maintenance with specified time intervals.

Levey-Jennings Chart quality control chart; a graph or table that shows results of control tests over a period of time; used in a quality control program.

Licensure the requirement that the laboratory receive a separate license, certification or accreditation from a governmental agency as a prerequisite of doing business.

Limited Regulation State a state in which the laboratory regulation program includes some but not all of the aspects of a full regulation state.

Lipemia (adjective lipemic) a condition in which too much fat or lipids are in the blood. A lipemic serum sample looks milky and turbid, and may produce erroneous results.

Lyophilized freeze-dried; a lyophilized calibrator, control, or reagent has been specially dried to make its analytes more stable. It must be refrigerated to maintain its stability, and is reconstituted by adding an appropriate diluent.

Linearity the measure of the range (the linear range) of concentration of an analyte over which a method or test produces consistent (i.e., linear, straight line) and accurate results.

Lysing Agents These agents rupture cells.

Mean the average of the numerical results obtained from a series of analyses.

Media The food that is used for culturing microorganisms.


Method analytical method; the instructions including procedures, material, equipment and everything else needed for an analyst to perform an analysis.

Microorganism a small, usually microscopic, living organism; types include bacteria, viruses, molds, yeasts, and protozoa .

Morphology the form and structure of an organism, organ, or part.

NCCLS National Committee for Clinical Laboratory Standards (publishes information manuals for laboratories)

Normal Values (expected Values, Reference Values) a range of values established for each analyte that includes the results expected when performing a test on a healthy person.

Out of Control term used to describe the testing procedure when the results from a control sample are outside the acceptable control range.

Oxidase Reagent In the office setting this reagent is used yo test organisms that are thought to be Neisseria gonorrhoea (GC).

Pathogen (adjective pathogenic) a microorganism that causes a disease.

Personnel Records There should be a personnel file on each member of the laborat ory staff. It should include a resume of training and experience, school transcripts (if relevant), formal certification or license (if this is required by your state), references, job description which delineates responsibilities, incident and accident records, records of continuing education, and copies of the performance evaluations.

Personnel Requirements education and experience requirements for the professional and technical laboratory personnel.

Pharyngeal Specimen This is a specimen from the throat used for performing a rapid antigen detection strep test or a throat culture.

Phlebotomy the cutting of a vein, or the puncture of a vein to collect blood. A phlebotomist is the person who collects blood by venipuncture (venous blood).

Photometry the measurement or analysis of light emitted by a substance. Reflectance photometry is the principle used in most instruments that read dry reagent strips.


Physicians' Office Laboratory a laboratory, located in a physician's office, used to perform tests or procedures as an adjunct to treating his or her patients.

Pipette a glass or transparent plastic tube used to measure small quantities of liquid. A volumetric pipette is an extremely accurate, single-line pipette used to reconstitute calibrators and controls.


Plasma

a centrifuge.


the liquid part of blood after it has been mixed an anticoagulant and spun down in


Plated This involves streaking, smearing, or depositing with a loop or pipette, some of a specimen onto the surface of solid food (media) that is used to grow microorganisms.

Plates Microorganisms are grown on special food (media) which is placed in a small plastic container ("petri dish"). This combination of media and plastic container is called a "plate."

Precision (re-producibility) the measure of the closeness of the results obtained when analyzing the same sample more than once; the measure of agreement between replicate measurements.

Procedure Manual a laboratory manual that contains the methods, materials, and other information needed to do a test.

Product Insert informational material that comes with instruments, reagents, and other laboratory products giving instructions for the use of the product and other information required of the manufacturer by the U.S. Food and Drug Administration.

Proficiency Samples analytes of unknown concentration that are sent to laboratories participating in proficiency testing programs.

Proficiency Testing a program in which samples are sent to a group of laboratories for analysis. The results are tabulated by the program's sponsor, and a participating laboratory can compare its results with those of other laboratories that use the same method.

Protocol a standard set of instructions for performing a procedure, such as a test or an evaluation. See the guideline on Method/Instrument Selection, Evaluation, and Operation.


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Quality Assurance/Assessment a comprehensive set of policies, procedures, and practices necessary to make sure that the laboratory's results are reliable. QA includes record keeping, calibration and maintenance of equipment, quality control, proficiency testing, and training.

Quality Control the set of laboratory procedures designed to ensure that the test method is working properly and that the results meet the diagnostic needs of the physician. QC includes testing control samples, charting the results, and analyzing them statistically.

Quantitative this term is applied to tests that give results expressing the numerical amount of an analyte in a specimen. This is in contrast to qualitative tests that detect whether a particular analyte, constituent, or condition is present.

Reactivity the ability of a reagent to produce its proper chemical reaction. Reagents can lose their reactivity if they are misused, mishandled, or too old.

Reagent a substance that produces a chemical reaction in a sample that allows an analyte to be detected and measured.

Reconstitute to add a diluent to a freeze-dried calibrator, control, or reagent.

Reference Interval see Normal Values.

Reference Materials It is sometimes necessary to determine the accuracy of a specific testing method. One way of doing this is to test materials with known accurately determined concentrations (target concentrations) for the method under investigation. These materials with the specified target values are called "reference materials."

Reference Ranges These are the limits of laboratory values of populations without disease.

Replicate to repeat an experiment or an analysis in order to check the accuracy of the results. Each repeat is a replicate (pronounced rep-Ii- kit) test or measurement.

Re-producibility see Precision.

Result the value obtained by analysis for a particular analyte in a particular sample.

Requisition This is a form of some kind which indicates the name of the patient, the date, the name of the physician requesting the test and the tests that are to be performed.


Run (analytical run) a group of measurements by a particular method over a period of

,,- time during which the accuracy and precision of the method are expected to be stable.

Sample the part of a specimen that is used for analysis.

Sensitivity the ability of a test to give a positive result for patients that have the disease or condition they are tested for; measured as the ratio of positive tests in those that have the disease; expressed as a percentage.

Serum the liquid part of the blood after it has coagulated and then been spun down in a centrifuge.

Specificity the ability of a test to give a negative result for patients that do not have the disease or condition they are tested for; measured as the ratio of negative tests to the total number of tests in those that do not have the disease or condition; expressed as a percentage.

Specimen the portion of a body fluid (for example, blood or urine) that is collected from the patient.

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Split-Sample Testing

dividing a sample in half, and testing half in your laboratory and

having the other half tested in another laboratory, and then comparing the results. This is a

technique for testing accuracy.

Stability the ability of a specimen, reagent, or control to maintain a constant concentration of the analyte. Reagents and controls must be handled and stored properly and used before their expiration dates to maintain their stability. Specimens must be collected, handled, and processed properly.

Standardization This is a formal process by which a measurable quantity produced by a chemistry instrument (this can be voltage) is related to the concentration of a particular chemical.

Standard, Primary a reference material that is of fixed and known chemical composition and capable of being prepared in essentially pure form. Also: Any certified reference material that is generally accepted or officially recognized as the unique standard for the assay regardless of its level of purity of analyte content.

Standard, Secondary a reference material, the analyte concentration of which has been ascertained by reference to a primary standard.


Standard Deviation a statistical measurement of the degree of variation from the mean ofa series of measurements. It is a measure of precision or re-producibility.

Test a procedure for detecting the presence or the amount of an analyte.

Titer the quantity of a substance required to produce a reaction with a particular amount of another substance. The amount of one substance required to correspond with a particular amount of another substance. Agglutination titer is the highest dilution of a serum that causes clumping of particulate antigens.

Throughput a term applied to analytical instruments specifying the number of tests that can be performed in a given time.

Toxic Hazards products used in the laboratory which may contain substances that pose some danger to the laboratory worker.

Toxicology the study of the origin, nature, and effects of poison. Toxicological analyses are used to detect the amount of a substance that can be poisonous at a particular concentration.

Turbidity (adjective turbid) cloudiness; distribution of a substance in a solution making it unclear or cloudy.

Value the statement of the number, in the units of the method, obtained for an analyte in a particular sample. See result.


Venipuncture

"venous blood."

Whole Blood


the procedure for collecting a blood sample from a vein. This is called

blood mixed with an anticoagulant but not spun down in a centrifuge.


References:

5. . COLA Checklist Glossary

6. . NCCLS Physician Office Laboratory Procedure Manual