Clinical performance requirements for lateral flow tests:

This is a specification of the clinically acceptable performance requirements for Lateral Flow Tests at the point of care.

It sets out the clinical requirements based on what is believed to be the ‘minimally acceptable’ in the opinion of UK IVD industry, healthcare professionals and medical device regulators given the emergency situation.

A test kit with other specifications than this may not be suitable to support the UK testing strategy.

The intended use of lateral flow tests that match these profiles (or one that does not yet meet the specifications but looks promising) is to aid in the triage of patients with a current Covid 19 infection by detection of Covid 19 nucleic acids or antigens in human samples.

The acceptable clinical sensitivity and specificity criteria are an initial estimate of minimally acceptable performance based on expert opinion in a potentially limited number of use cases. Note that the expert opinion develops over time. Examples of potential use cases of such devices from FIND.

To ensure ongoing safety, value for money, procurement and deployment of lateral flow tests should take into account specific clinical decision and pathway changes the test is being used to make, the current and future prevalence of Covid 19 within the intended test population.

Along with potential consequences of the false positives and false negatives. For example, the clinical sensitivity and specificity may need to be higher for some uses of the lateral tests.

For example, in populations with a low amount of COVID-19 in the population there needs to de an even higher specificity to prevent the probability that a positive test result is a true positive (positive predictive value) from being too low.

The tables below which may be useful in supporting decision making, by demonstrating the impact of changing sensitivity, specificity and prevalence on the numbers of false positives and negatives for lateral flow tests.

For example, tests with a low sensitivity may have limited utility in ruling-out Covid 19 in patients, especially if rule-out may expose others to infection.

Similarly, tests with a low specificity may have limited utility in ruling-in Covid 19 patients, especially if this may expose uninfected patients to infection, for example by being transferred to a COVID ward.

When used for triage, it may be possible to reduce the potentially harmful consequences of an insensitive or unspecific test. How: By confirming negative or positive point of carre results using a more accurate, but slower diagnostic test, such as conventional lab based methods such as PCR tests.

The advantage of the point of care lateral flow tests here could be that at least a proportion of people with, or without, COVID-19 can be managed faster than relying on conventional lab based testing alone.

The criteria are based on similar Target Product Profiles published by the World Health Organisation, PATH, and FIND for IVDs to other diseases.

See also: Guy's and St Thomas Lateral Flow tests comparative Study 2021.

European Respiratory Society lateral Flow tests Study

University of Mexico's Clincial study of Lateral flow tests.