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Flashcards in Case unit 6 Deck (11):

test parameters from imaging

shape, size, number, specific molecule
Scoring systems often used
Subjectivity can be an issue
Expert opinion often required


when designing a test what do we need

something that marks the disease and is different in healthy and ill indivduals


what are volatile organic compounds

present in sweat, urine, poo and breath
metabolic products
quick, cheap and non-invasive


what is cell free DNA

circulating tumour (ct)DNA
DNA released into the blood
tumour and normal cells
non-invasive test
liquid biopsy
PCR - Sequence certain DNA to detect genes
allows you to detect certain tumours by genes


use of GWAS as a screening method

GWAs correlates the presence of genetic variants with the risk of developing a disease
Identification of an individual SNP profile may indicate risk of developing a condition



the proportion of people with the disease who will have a positive result. In other words, a highly sensitive test is one that correctly identifies patients with a disease.
Also called the true positive rate



the proportion of people without the disease who will have a negative result. In other words, the specificity of a test refers to how well a test identifies patients who do not have a disease.
also called the true negative rate


Positive predicitve value

probability that a positive result in a hypothesis test means that there is a real effect. It is the probability of patients who have a positive test result actually having the disease.


PPV calculation

PPV = number of true positives / number of true positives + number of false positives
PPV = Sensitivity x Prevalence / Sensitivity x prevalence + (1- specificity) x (1-prevalence)


Specificty calculation

True negative/ true negative + false postive


sensitivity calculation

true positive/ flase negative + true positive