Applications of Lateral flow test

Lateral flow analysis has a wide range of applications and can test a variety of samples such as urine, blood, saliva, sweat, serum, and other fluids.They are currently used by clinical laboratories, hospitals and physicians to perform rapid and accurate tests for specific target molecules and gene expression.Other uses of lateral flow analysis are food and environmental safety and veterinary medicine for chemicals such as diseases and toxins.LFTs are also commonly used to identify diseases such as Ebola, but the most common LFT is a home pregnancy test.

COVID-19 testing 

Lateral flow assays have played a key role in COVID-19 detection as they have the advantage of providing results within 15-30 minutes. As part of a UK collaboration with Public Health England, the University of Oxford initiated a systematic review of lateral flow analysis during the COVID-19 pandemic.A study called FALCON-C19, which started in June 2020 in the UK, confirmed the sensitivity of some lateral flow devices (LFDs) in this situation. [29][30][31] Based on these early tests, four of the 64 LFDs tested had desirable performance characteristics; the Innova SARS-CoV-2 Antigen Rapid Qualitative Test performed moderately in terms of viral antigen detection/sensitivity with excellent specificity, although kit failure rates and training effects are potential concerns.The specificity of the Innova test is more widely advertised, but the sensitivity of the phase 4 trial was 50.1%.This describes a device where one in two patients infected with COVID-19 and tested under real-world conditions would receive a false negative result.Following school closures in January 2021 England introduced fortnightly LFTs for asymptomatic testing for teachers, pupils and pupil families when schools reopen on 8 March 2021.On 9 April 2021, the fortnightly LFT opens to everyone in England.LFT has been used globally for mass detection of COVID-19 and complements other public health measures against COVID-19.Some scientists outside the government expressed serious misgivings in late 2020 about using the Innova LFD to screen for Covid.Jon Deeks, professor of biostatistics at the University of Birmingham in the UK, said the Innova test was "totally unsuitable" for community testing: "As the test may miss up to half of cases, a negative test result indicates but does not rule out Covid.The sensitivity of the test used in 2022 is about 70%.

Sensitivity and specificity

Sensitivity and specificity mathematically describe how accurately a test reports the presence or absence of a condition.If people with the condition are considered "positive" and those without the condition are considered "negative," then sensitivity is a measure of how well a test identifies true positives, while specificity measures how well a test identifies true positives Index Negatives of Degree:Sensitivity (true positive rate) is the probability of a test result being positive, conditional on an individual actually being positive.Specificity (true negative rate) is the probability of a negative test result, conditional on an individual being truly negative.If the true state of the condition cannot be known, sensitivity and specificity can be defined relative to a "gold standard test" that is assumed to be correct.As with all tests, including diagnostics and screening, there is usually a trade-off between sensitivity and specificity, so higher sensitivity will mean lower specificity and vice versa.A test that can reliably detect the presence of a condition so as to generate a large number of true positives and a small number of false negatives will have high sensitivity.This is especially important when the consequences of failing to treat the condition are severe and/or when the treatment is very effective with minimal side effects.A test that reliably excludes individuals without this condition, resulting in a large number of true negatives and a small number of false positives, will have high specificity.This is especially important when people identified as having a disease may be subject to additional testing, fees, stigma, anxiety, etc.