Case unit 6 Flashcards Preview

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Flashcards in Case unit 6 Deck (11):
1

test parameters from imaging

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

2

when designing a test what do we need

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

3

what are volatile organic compounds

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

4

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

5

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

6

Sensitivity

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

7

Specificty

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

8

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.

9

PPV calculation

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

10

Specificty calculation

True negative/ true negative + false postive

11

sensitivity calculation

true positive/ flase negative + true positive