An in vitro diagnostic (IVD) test is used for a wide variety of reasons medically but predominantly to give doctors and other healthcare professional more information to inform clinical decisions. Most tests will not lead to a diagnosis on their own but will make up the clinical picture.

Test are not just used for diagnosing disease but also for monitoring treatment and existing conditions such as diabetes, deciding which drugs to use, and screening for disease in at-risk sectors of the population. They are also important for ruling out causes of disease.

They are also used to test donated blood for infection.

IVDs are widely used in hospitals in all the specialities in the pathology department and also on wards, in A&E, ICU and operating theatres.

Most people are aware of pregnancy tests available in high-street pharmacists, and many are aware of the blood glucose monitors used by people with diabetes to help manage their therapy.

The IVD Industry is developing many more tests in designs specifically for home use, such as those used to monitor coagulation therapy, or to screen for various forms of cancer. Products to help pinpoint a woman's most fertile stage in her menstrual cycle, to screen for the biochemical markers associated with osteoporosis, and simple tests for urinary tract infection are amongst those arriving on the pharmacists' shelves.

Although all self-testing products have extensive information in the packaging explaining their use, the pharmacist will also be willing to discuss any questions about them that the consumer might have. BIVDA advises anyone with concerns about their health to speak to their GP, self-test results can be useful to aid this discussion.

Anyone who has visited a medical laboratory will know that it is a "high tech" world, with automated machines testing hundreds of samples a day. Many hundreds of sample components can be measured, but usually between two and ten are measured for each sample. Some tests (for example biological cultures) take time, but most results are available within minutes or even faster in the case of an emergency situation.

The results are sent to the doctor in the form of a laboratory report for each sample that gives the results in comparison with normal values. In many cases the doctor will discuss the results with and request additional information from specialists in the medical laboratory.

Moving diagnostic tests to the point of care (POC) has the potential to alter substantially the delivery of care to patients, allowing timely diagnosis of patients at the bedside, in general practice, or in the community.

POC testing is an area of in vitro diagnostics (IVD) that has been gaining momentum over recent years and is now recognised as having a major role to play in redesigning services around the needs of the patient.

You can read more about the benefits of POC testing in our case study New Models of Care (page 8).

There is nothing new about genetic testing itself, but the technologies now available will allow a more reliable estimation of the risks of disease that individuals have because of their genetic make-up but the term also covers testing the genetic material of micro-organisms causing infection in order to be able to identify and treat them more precisely.

Information on an individual’s genome will be increasingly valuable to establish their reaction to different commonly used drugs, predict health issues and allow identification of rare and inherited disease. It is likely that conditions such as sickle cell anaemia and cystic fibrosis will be treated in the near future by ‘editing’ an individual’s genes ( known as gene splicing).

Companion diagnostic is a term used for a test which is used to determine which patient or group of patients will respond to a drug therapy. The diagnostic test is used first so a better term would be diagnostic dependent drugs. Most of the examples for these are in cancer currently but it is anticipated that even quite commonly used drugs will require a test before prescribing in the future to determine if they will be effective for the individual or for tailoring the dosage. This means people will not be at risk of suffering side effects from drugs which will not benefit them.

Many cancer patients already feel they ‘failed the test’ for a treatment. This is nothing to do with rationing of drugs or anything they have done but means that their tumour does not produce a chemical which the drug targets so it will not work for them.

The importance of in vitro diagnostics (IVDs) in tackling the antimicrobial resistance (AMR) challenge cannot be overstated.

While the widespread use of broad-spectrum antibiotics has helped to create multi-drug resistant strains of bacteria, greater adoption of IVDs would lead to a reduction in cases of unnecessary antibiotic prescribing by:

  • Reducing time to appropriate treatment decision
  • Allowing for a more targeted use of therapy against infection

Urgent action is required to halt AMR and we strongly urge healthcare professionals in the UK to make use of the quick, accurate and effective IVDs already available to them. Until IVDs are more widely adopted, we will not be able to combat AMR effectively.

An in-house test is a test which:

  • Has been designed and developed in a public health or NHS laboratory and with reagents produced in the laboratory
  • Is used off-label- i.e. a commercial test which is CE marked but where the user does not comply with the manufacturer’s instructions for use in some significant way
  • Used for a clinical purpose for which it has not been designated by the manufacturer
  • Is not CE-marked but is sold for Research Use Only where the results are used to support clinical decisions or disease management

To learn more about in-house testing, please read our report: Safe and consistent? The regulation of pathology testing.