Amplification Test - A test which replicates the genetic material (DNA or RNA) of a microorganism such as chlamydia from a few copies to millions within a few hours. These amplified (replicated) copies can then be detected, usually by photometry or fluorimetry.

Analytical Range - The range of accuracy of a test, e.g. the values (results) of a glucose blood level may range from 10 to 10,000 units. However, if test A used to detect glucose is only capable of detecting from 100 to 1,000 units, then the analytical range of this test is 100 to 1,000 units.

Antibiotic - A chemical substance capable of destroying microorganisms, specifically bacteria.

Antibody - A type of serum protein that is produced by the body in response to bits of foreign organisms (antigens). Antibodies assist the body in removing or destroying foreign antigens and their associated organisms.

Antigen - Foreign substances (usually bits of organisms) that often stimulate the body to produce antibodies. Such substances may also be used in the lab to detect antibodies in the blood stream.

Asymptomatic - A state where a person is infected with a disease but has no clinical symptoms.

APHL - The Association of State and Territorial Public Health Laboratory Directors. The national organization of public health laboratory directors and workers representing state and territorial health departments.

Azithromycin - An antibiotic used to treat chlamydial infections that can be given in a single dose.

Batch - A set of specimens (e.g., endocervical swabs) processed and tested during a single run (diagnostic test).

Cervicitis - Infection and/or inflammation of the cervix. Can be a sign of chlamydial infection.

Cervix - The narrow neck of the uterus, which extends into the vagina.

Chlamydia trachomatis - Chlamydia trachomatis is the bacterial agent which causes chlamydial infections, the most common sexually transmitted bacterial infection in the United States. While chlamydia is classified as bacteria, they share some properties of both bacteria and viruses, and they reproduce only inside of epithelial cells.

CLIA - Clinical Laboratory Improvement Act of 1967 (and amendments of 1988) which sets the guidelines for any clinical laboratory which tests materials obtained from human patients, e.g.; blood, tissue, swabs, etc. CLIA is administered through the U.S. Health Care Financing Administration (HCFA).

Clinical Laboratory - A laboratory in which tests directly related to the care of patients are performed. Such laboratories use material obtained from patients for test, as compared with research laboratories, where animal and other sources of test material are also used.

Clinical Laboratory Procedure - Analytical procedure (test) performed on any specimens (samples) taken from humans and used to diagnose disease or infection.

Collection Sites - Locations in the body from which a chlamydia specimen may be taken. These sites include: cervix, urethra, rectum, throat, conjunctiva (eye).

Confirmatory Test - A test which is used to confirm positive screening results in order to minimize false positive results thereby improving specificity. This test employs a different target molecule than the screening test, e.g., C. trachomatis enzyme immunoassay (EIA) typically detects specific lipopolysaccharide (LPS); while direct fluorescent antibody (DFA) test, used to confirm a positive EIA test, targets the major outer membrane (MOMP) of C. trachomatis. This method is preferred to using a supplemental test (see Supplemental Test).

Control - An artificial specimen with a known value (i.e. positive or negative) which is included in every test run in order to monitor the performance of the test. For example, if the positive control would test negative, it would invalidate the results of that particular test run and specimens would have to be retested.

CSTE - Council of State and Territorial Epidemiologists. This is the national organization of epidemiologists working in state health departments.

Culture - A laboratory test involving the cultivation of microorganisms or cells in a special growth medium.

Cutoff (CO) - A mathematically derived calculation in any given immunoassay which is used to determine which specimens are positive (reactive) or negative (non-reactive). Generally specimens with values above the CO are positive and those below are negative.

Diagnostic Test - A test designed to detect chlamydia in a patient presenting with symptoms or risk history, as distinguished from a screening test.

Direct Fluorescent Antibody Test (DFA) - The direct detection of chlamydia (antigen) from a specimen (e.g., endocervical swab, etc.) which is placed on a microscope slide and stained using fluorescently labeled chlamydia specific antibody. After proper staining, the slide is viewed under a fluorescence microscope. Chlamydiapositive specimens show apple-green elementary bodies in contrast to red background of counterstained cells.

DIS (Disease Intervention Specialist) - A trained individual working with patients testing positive and their partners to confirm treatment and identify all other potentially infected individuals. Usually employed by a state or local health department.

DNA Probe - See Nucleic Acid Hybridization Test.

Doxycycline - An antibiotic used to treat chlamydial infections. The standard dosage for treatment of chlamydia is 100 milligrams twice a day, for 7 days.

Ectopia - Visible columnar epithelial cells that extend onto the outer surface of the cervix. In younger women or women using hormonal contraceptives, ectopy is considered normal. However, ectopy increases the risk of acquiring chlamydia by exposing the more vulnerable columnar epithelial cells.

Enzyme Immunoassay (EIA) - A laboratory test that detects specific antigens or antibodies rather than the organism (e.g., chlamydia) itself.

Erythromycin - An antibiotic used to treat chlamydial infection, especially for pregnant women. The standard dosage is 500 mg orally 4 times a day for 7 days.

Etiologic Agent - An agent that causes disease.

External Quality Control - An external control (see control) specimen which is generally shared between multiple laboratories and the results compared for quality control purposes.

False-Negative (Rate) - The rate of occurrence of negative test results in subjects known to have the disease or behavior for which the individual is being tested. The rate of occurrence of false-negative results varies with the diagnostic accuracy and the specificity of the test or procedure and the pre-test likelihood of disease. As the accuracy and specificity of a test increase, the rate of false negatives decreases. As the pre-test likelihood of disease increases the false negative rate also increases (except when sensitivity is 100%). Certain tests are known to yield false-negative results at a certain rate; in all tests, a small number of false negatives will occur by chance alone.

False-Positive (Result) - A test result that wrongly indicates the presence of a condition when the condition is not present.

False-Positive (Rate) - The rate of occurrence of positive test results in tests of individuals known to be free of a disease or disorder for which the individual is being tested. The rate of occurrence of false-positive results varies with the diagnostic accuracy and the specificity of the test or procedure and the pre-test likelihood of disease. As the accuracy and specificity of a test increase, the rate of false positives decreases. Certain tests are known to yield false-positive results at a certain rate; in all tests, a small number of false positives will occur by chance alone.

Friability - Fragile, easily crumbled, especially prone to bleeding; for example, cervical tissue in some chlamydial infections.

Gray zone (GZ) - An artificially established range (zone) below a diagnostic test's cut-off (CO) value. The GZ generally ranges from 30-70% below the CO. Specimens in the established GZ are then re-tested by another methodology in order to increase the test sensitivity, i.e., to detect additional positive specimens.

Infertility - The inability to conceive or carry a fetus to term. Chlamydia-related infertility is most often caused by scarring in the fallopian tubes.

Inhibitor - A substance that interferes with the test's ability to detect the presence or absence of disease. Blood and mucus are examples of potential inhibitors for chlamydia.

Internal Quality Control - An internal control specimen made up and used by a particular laboratory (see control).

Lot - Diagnostic kits are manufactured in large quantities (lots). As part of quality control, laboratories record all results from each kit and lot in order to monitor for any variations which may occur among lots.

MOMP - The Major Outer Membrane Protein on the chlamydia organism. The MOMP is species-specific, i.e., C. trachomatis is different from C. psittaci, etc. Any test which detects MOMP will only react with each separate species, i.e., antibody against C. trachomatis MOMP will not react with C. psittaci.

Mucopurulent - Green or yellow discharge when viewed on a white cotton swab that has been inserted into the cervical os.

Package Insert (Medication) - The written pamphlet for each prescription drug listing side effects, dosages, indications, contraindications, drug interactions, etc.

Partner Notification - The process of identifying sex partners of patients testing positive and informing them that they are at risk for infection and need to be tested.

Pelvic Inflammatory Disease (PID) - A clinical syndrome identified by a range of symptoms including lower abdominal pain and tenderness, bilateral adnexal tenderness, low-grade fever, and cervical motion tenderness. Serious sequelae (consequences) can include infertility, ectopic pregnancy, and chronic pelvic pain. PID can be one of the serious consequences of chlamydial infections.

Polymerase Chain Reaction (PCR) - DNA amplification test for chlamydia.

Predictive Value (Negative) - The likelihood that a person with a negative test does not have the disease, or in a group, the proportion of all negative tests that actually reflect a disease-free state.

Predictive Value (Positive) - The likelihood that an individual with a positive test has the disease, or in a group the proportion of all positive tests that actually reflect a disease state.

Presumptive Treatment - Also known as epidemiologic treatment. The treatment of patients suspected of having a disease based on identified risk factors and/or clinical findings without the confirmation of a test result.

Prevalence - The percentage of people in a given population that have a given disease, e.g., the prevalence of chlamydia in Clinic A is 5% that is 5 out of 100 individuals in Clinic A are infected with chlamydia.

ProbeTec - An amplification test for chlamydia. A process whereby a strand of DNA can be cloned (replicated) millions of times within a few hours by strand displacement amplification (SDA).

Proficiency Testing: (PT) - A program (CAP, AAB, etc.) in which samples (artificial patient specimens) are sent to participating laboratories for analysis. The true value (results) of the samples are unknown by the testing laboratory. The results are reported to the specific program (CAP, AAB, etc.) tabulated, compared to all participating laboratories and reported to the enrolling laboratory. PT specimens are an indicator of laboratory performance.

Quantitative - A test that is quantitative determines the amount of a substance per unit volume or unit weight, e.g., blood glucose normal range 70-115 mg/dl-milligrams per deciliter.

Quality Assurance Program (QAP) - A comprehensive set of policies, procedures, and practices used to monitor the services provided in a clinical or laboratory setting. These plans should include protocols for proper record keeping, calibration and maintenance of equipment, monitoring of quality controls and proficiency testing results, and training.

Quality Control (QC) - The set of laboratory or clinical procedures designed to ensure that a test is working properly, e.g., test controls, monitor lot-to-lot variation, monitor/run CO values, etc.

Screening Test - A test performed to detect chlamydia in a patient presenting for a routine exam, with no symptoms or risk history indicating chlamydia, as distinguished from a diagnostic test.

Selective Screening - Testing for chlamydia in a population using screening criteria, as opposed to universal screening of an entire patient population, or diagnostic testing of patients with symptoms.

Sensitivity - The ability of a test to accurately detect patients who have the disease or condition for which they are being tested.

Specificity - The ability of a test to accurately identify patients who do not have the disease or condition for which they are being tested.

Specimen - A small sample of something, intended to show the nature of the whole, e.g., a blood or urine specimen.

Specimen Adequacy - The quality of the specimen obtained from the patient judged by the number and type of cells sampled, e.g., in chlamydia testing, an endocervical specimen which contains any endocervical columnar epithelial cells.

Strand Displacement Amplication (SDA) - A DNA amplification method.

Supplemental Test - A test which is used to confirm positive screening results. This test employs the same target molecule as the original screening test, e.g., C. trachomatis enzyme immunoassays (EIA) typically detect specific lipopolysaccharide (LPS); the EIA blocking or neutralization assay also target this same molecule (LPS). As a general rule, results obtained from using one test should be confirmed using an alternate technology (see Confirmatory Test) in order to best decrease the incidence of false positive test results thereby increasing specificity.

Symptomatic - Presenting with clinical signs or symptoms of disease.

Transcription Mediated Amplification (TMA) - RNA amplification test for the detection of chlamydia.

Turnaround Time (TAT) - The amount of time it takes to produce a test result from the time a specimen is received in the laboratory until it is reported out.

Urethritis - Inflammation of the urethra.

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