Diagnostics

Question 1

airport scanners are very

Answer 1

sensitive tests

- they always go off

Question 2

airport scanners aren’t very

Answer 2

specific

- most who set them off re not carrying a gun

Question 3

BUT

Answer 3

no one with a gun will get through

Question 4

often high sensitivity tests

Answer 4

have more specific tests after e.g. one of the more technical airport signals

Question 5

further tests are usually

Answer 5

time-consuming
expensive
more invasive

Question 6

example of a sensitive test

Answer 6

HIV testing in blood donor is very sensitive- it is better to throw away a good sample than give infected blood

Question 7

example of specific test

Answer 7

diagnosing need for kidney transplant is very specific

-it is better not to throw away a good kidney

Question 8

the important elf a good diagnosis

Answer 8

correct therapy can be used.g. T1 vs T2, which cancer?

Question 9

early detection

Answer 9

gives better prognosis

Question 10

diagnosis and screens

Answer 10

a poorly person may visit a doctor- clinical knowledge/ diagnostic tests

Question 11

an ‘at risk’ population may be

Answer 11

screen- often requires clinical referral and subsequent tests for a diagnosis

Question 12

what can we use for a diagnostics

Answer 12

something measurable that is different in affected group

Question 13

symptoms

Answer 13

spots, never, swelling, bleeding

Question 14

physiology

Answer 14

temp, bp, spirometry, eGFR

Question 15

Blood-borne

Answer 15

hormone levels, blood glucose, inflammatory mediators, PSA, genetic markers, antibodies

Question 16

biopsy-based

Answer 16

cancer antigens, cancer histology, leukocytes, genetic markers

Question 17

what is required for diagnosis

Answer 17

an accurate diagnostic cut-off

Question 18

the diagnostic cut off lies between

Answer 18

true negatives (healthy) and true positives (diseaseO

Question 19

Joy’s nose- t shirt sampling smell test for 12 individuals

• 6 diagnosed with parkinson’s
• 1 undiagnosed
• 5 healthy

Answer 19

she was 100% sensitive- no missed cases

and 100% specific- no wrong cases

Question 20

some people with the disease will be

Answer 20

called negative and some people without the disease will be called positive

Question 21

VOCs

Answer 21

volatile organic compounds

Question 22

VOCs are present in

Answer 22

sweat, urine, poo and breath

• metabolic products
• quick, cheap, non-invasive
  e. g. dogs smelling for cancer

Question 23

imaging

Answer 23

e.g. IPF scan, x rays, histology, karyotyping

Question 24

parameters used in imagine

Answer 24

size, shape, number

• scoring system often used
• subjectivity can be an issue
• expert opinion sometimes required

Question 25

imaging is...

Answer 25

expensive, timely and generally used as an end diagnostic

Question 26

automated detection?

Answer 26

e. g. taking photos of a mole | - could help with early detection- better prognosis- cheaper to treat

Question 27

DNA as a biomarker:

Answer 27

- infection (PCR) - monogenic disease- sequence candidate genes - SNps - cell free (cf) DNA

Question 28

cell free DNA

Answer 28

e.g circulating tumour (ctDNA)

Question 29

ctDNA

Answer 29

- liquid biopsy--> PCR --> amplify target genes often mutated in cancer --> DNA sequencing of target regions - DNA released into blood - tumour and normal cells - non-invasive

Question 30

trisomy screening- current guidelines

Answer 30

11-13 weeks- combined test which is quick and easy - measure nuchal translucency (PAPP-a_, (HcG) and mother are - combine to generate risk score

Question 31

if risk is 1 in 150, amniocentesis is offered

Answer 31

4% risk of miscarriage | - but the gold standard

Question 32

gold standards are thought to be

Answer 32

diagnostic

Question 33

new method for detection of trisomy

Answer 33

around 15% of cFDNA in pregnant women comes from embryo cffDNA (cf fatal DNA) - non invasive rental screen for trisomy - using NGS- tell us how many copies of DNA - fetal DNA will be different to maternal DNA - compares fatal and maternal ratios

Question 34

new method for detection of trisomy implementation

Answer 34

being introduced tis year, however it is an expensive process, so only higher risk patients (combined test score) referred.

Question 35

SNPs and GWAS

Answer 35

GWAS correlated the presence of genetic variations (SNPs) with the risk of developing a disease - identification of an individual SNP profile may indicate risk of developing a condition e. g. a panel of 18 SNP has been shown to help predict risk of family breast cancer

Question 36

diagnosing the mind is hard

Answer 36

- how do you get a firm diagnosis of the mind e.g. Trump - a diagnosis can be classification of behavioural treats - is there a real condition? - is it useful to have a diagnosis of internet gaming disorder?