case unit 6 - diagnostics Flashcards Preview

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Flashcards in case unit 6 - diagnostics Deck (24):
1

what does specificity test

how many people are healthy

2

what does sensitivity test

how many people actually have the disease

3

if the sensitivity is 84%

then 84% of people with the disease will be correctly tested as +ve

4

if the specificity is 53%

then 53% of healthy people will be correctly tested -ve

5

importance of a good diagnosis

correct and appropriate therapy can be prescribed
better prognosis
early detection

6

reasons why a diagnosis would be made

if a sick person visits the doctor
if an 'at risk' population gets screened
- clinical referral and subsequent tests may follow this

7

what types of measurements may be taken in a diagnosis

symptoms e.g. spots, fever
physiology e.g. temp, bp
blood-borne e.g. blood hormone/glucose levels
biopsy-based e.g. cancer antigens
other e.g. questionnaire, voc

8

what are VOCs

volative organic compounds

metabolic by-product of the disease present in swear, breath, urine, poo

9

disadvantage of measuring VOCs

each measurement could represent a combination of substances

10

why are VOCs a good diagnostic measure

non-invasive
quick
cheap

11

what is the diagnostic cut-off

vertical line between those that test +ve and -ve on rgpah

anyone above the cut off line has the disease
anyone below is healthy

overlap in the distributions gives false results

12

types of imaging used in diagnosis

x-rays
histology
karyotyping

13

disadvantages of imaging as a diagnostic tool

expensive
subjective
requires expert consultation
invasive - often used as an end diagnosis

14

use of automated diagnosis

e.g. detection of melanomas
AI used to recognise malignant moles from photo analysis
consultant standard
t-SNE visualtion used to detect different carcinomas

15

use of DNA as a biomarker if they think you have the disease

use PCR
sequence candidate genes for monogenic diseases

16

use of DNA as a biomarker if they are unsure whether you have the disease or not

test your cell free (cfDNA) for SNPs

17

use of cfDNA in cancer

DNA is released into your blood
e..g ctDNA (circulating tumour)
purify cfDNA
amplify the target genes (those that are commonly mutated in cancers e.g. p53, Ras)
sequence target regions

18

advantages of using cfDNA

non-invasive
like a liquid biopsy

19

disadvantages of using ctDNA

often low presence of ctDNA in blood
different ctDNA characteristics among patients

20

what are micro-vesicles

membrane fragments released into the blood

21

what is the new trisomy screen

NIPS - Non-invasive pre-natal screen
mothers blood sample also contains foetal DNA
cf-DNA tested
next gen sequencing used

22

advantages of the new trisomy screen (NIPS)

more sensitive and more specific test

23

diagnosis of mental capabiltiy

hard
classification of behavioural tests (think trump test)
DSM-5

24

what is DSM-5

diagnostic and statistical manual of mental disorders