Diagnostics ABC: all you need to know about diagnostics terms

These days, the media is full of news about diagnostic tests. But how much do you actually know? Here’s what you need to know to shine in every discussion about testing.

Antibodies are proteins that help fight infections. An antibody test is a blood-based test used to determine whether a person was exposed to and might have gained immunity against a pathogen (a bacterium, virus, or other microorganism that can cause disease).

An antigen is the part of a pathogen that causes an immune response. An antigen test detects proteins specific to that pathogen (a bacterium, virus, or other microorganism that can cause disease).

CE marking indicates that a test has been assessed by the manufacturer and deemed to meet EU safety, health and environmental protection requirements. It is required for products manufactured anywhere in the world that are then marketed in the EU or in non-EU countries accepting the CE mark.

Clinical (bio-)chemistry is the area of chemistry that is generally concerned with analysis of bodily fluids for diagnostic purposes. These are performed on any kind of body fluid, but mostly on serum or plasma. Serum is the liquid that remains after the blood has clotted. Plasma is the liquid that remains when clotting is prevented with the addition of an anticoagulant.

Clinical sensitivity indicates the ability of a test to correctly identify patients that have the pathogen, disease or condition (“true positives”).

Clinical sensitivity indicates the ability of a test to correctly identify patients that have the pathogen, disease or condition (“true positives”).

A companion diagnostic is a test that provides information for the safe and effective use of a specific treatment. The test is critical to help healthcare professionals determine whether a particular treatment’s benefits to patients will outweigh any potential serious side effects or risks. Companion diagnostics are most commonly used with targeted treatments for cancer.

Consumables are disposable parts such as tips, plates, sealing foils, cassettes, containers and bottles.

Diagnostics play a critical role in healthcare. They aid in disease prevention, screening, diagnosis, monitoring and treatment.

A false negative occurs when a test result improperly indicates no presence of a pathogen, disease or condition, when in reality it is present.

A false positive occurs when a test result improperly indicates the presence of a pathogen, disease or condition, when in reality it is not present.

In the United States, the development, manufacture and marketing of commercial tests are regulated by the U.S. Food and Drug Administration (FDA). Many tests must be evaluated and approved by the FDA.

An Emergency Use Authorization means that the US FDA is allowing not-yet-approved medical products to be used in an emergency – for example, the COVID-19 pandemic – to diagnose, treat or prevent serious or life-threatening diseases or conditions when there are no adequate, approved and available alternatives.

Highly automated systems are very sophisticated pieces of robotics that significantly reduce manual steps in the lab, reducing the risk of errors and enhancing patient safety and process quality.

A high throughput instrument in a highly automated machine or combination of machines that allows high volumes of testing over a short period of time.

Immunodiagnostics is a diagnostic methodology that uses antibodies for the identification of pathogens as the primary means of detecting infectious diseases, tumours, drug abuse, diabetes, proteins, therapeutic drugs, and allergens.

Systems are very sophisticated pieces of robotics used to run and automate diagnostics tests. Some instruments are stand-alone while others may form part of a system.

In-vitro diagnostics are tests done on samples such as blood, tissue or urine that have been taken from the human body. They provide objective information used for disease detection, management, and prevention. They influence roughly two-thirds of clinical decision making while accounting for just 2% of healthcare spending.

Molecular diagnostics help identify pathogen, disease or condition by studying molecules, such as proteins, DNA, and RNA, in patient samples.

The polymerase chain reaction (PCR) technology allows to amplify small amounts of genetic material (DNA or RNA) and has enabled major leaps in disease diagnosis and monitoring, e.g. for HIV.

Reagents are complex mixtures of biochemicals or chemicals used in in-vitro diagnostic testing. Example: “Lysis buffer” is a reagent used in SARS-CoV-2 testing to break open cells and/or viruses in order to identify their genetic make-up to confirm whether a patient has the virus.

Samples are small quantities of human material- blood, urine or tissue to be analysed. Auxiliary devices such as swabs are sometimes used to collect those samples.

Serology tests are blood-based tests used to identify antibodies and antigens in a patient's sample.

An assay is used to test for the presence or to determine the concentration of specific components in the human body --proteins, nucleic acid, infectious agents, cancer cells, etc. Assays help address the screening, diagnosis, monitoring, prevention and treatment of disease.

Test kits are packaged sets of reagents that make up a test for customer use.

Tissue diagnostics focus on the analysis of biopsies or other tissue samples from the human body. They are mostly commonly used for cancer detection, evaluation and management.

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