Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Y2 MCD > Diagnostics > Flashcards

Diagnostics Flashcards

1
Q

What do the different coloured caps represent on blood sample tubes?

A

o RED top = no anticoagulant

o YELLOW top = have gel to speed up clot

o PURPLE top = have potassium EDTA

o GREY top = have fluoride oxalate (poison)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why would you want potassium EDTA in the sample tube?

A
  • keep the cells alive -> for test involving RBCs, WBCs or platelets
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why would you want fluoride oxalate in the sample tube?

A
  • a poison that kills RBCs -> used to measure blood glucose -> if RBCs are alive they will consume the glucose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What colour capped tube is used for U&E?

No action

Mouse Gestures

Back

Forward

Scroll up

Scroll down

Switch to previous tab

Switch to next tab

Close all tabs except current

Close current tab

Open new tab

Close all tabs

Refresh current tab

Stop loading

Scroll to bottom

Scroll to top

Reopen closed tab

Go to home page

A
  • serum in yellow or red
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What colour capped tube is used for glucose?

A
  • plasma in grey
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What colour capped tube is used for HBA1c?

A
  • plasma in purple
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What colour capped tube is used for TFT?

A
  • serum in yellow or red
  • any hormone goes in a yellow or red top
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What colour capped tube is used for liver function tests?

A
  • yellow or red top
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a blue top container used for?

A
  • contains citrate -> an anticoagulant
  • used to measure clotting factors
  • is reversible which makes it useful
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

When do you need to contact a chemical pathologist?

A
  • want the sample to be rapidly centrifuged out of hours
  • want to measure labile hormones such as insulin
  • urgently need CSF glucose and protein to be measured -> meningitis (or another bacteria then they will consume the glucose) and as lumbar puncture is usually only done when a patient is very ill
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a maculopapular rash and name one disease associated wih it?

A
  • some raised areas and some flat covering the entire body
  • measles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Define a dermatomal rash and name a disease in which it is featured.

A
  • a rash confined to a few dermatomes
  • shingles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What can be detected in a virology lab?

A
  • Infectious Virus -> virus isolation and electron microscopy
  • Protein Components (antigens) on the virus -> e.g. p24 antigen in HIV, surface antigen in HBV etc.
  • Genetic Components of the virus (DNA or RNA)
  • Host Response -> antibody or cell responses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Define sensitivity.

A
  • the test’s ability to correctly identify positive samples
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Define specificity.

A
  • the test’s ability to correctly identify negative samples
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which antibody is a marker of recent infection?

A
  • IgM
  • IgG comes later on
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What samples are typically sent off for virology testing?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the 4 main diagnostic techniques used in bacteriology labs?

A
  • culture
  • serology
  • molecular techniques
  • anti-microbial suspectibility testing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Name the main use of cultures.

A
  • work out what antibiotic to use
20
Q

What are the major problems with cultures?

A
  • takes about 24 hours to grow the bacteria and another 24 hours to do the susceptibility testing
  • good in sterile sites (CSF, blood etc), because there should NOT be any bacteria so an grows is abnormal -> however in non-sterile sites (skin or gut), there are loads of bacteria that could have colonised but may not be causing any problems
21
Q

When is serology used?

A
  • to check the bodies response to infection
  • if the organism can’t be cultured -> syphilis
22
Q

Why are molecular techniques not commonly used?

A
  • rapid and sensitive but there is a range of resistance genes
  • is good for MRSA as the encoded resistence is in the MecA gene
23
Q

Which of the four main bacteriology tests is the most useful to doctors in general?

A
  • antimicrobial suspectibility testing -> checks to see if antibiotics are effective on the bacteria
24
Q

Describe the process leading to a positive blood culture diagnosis.

A
  • blood is added to broth inside bottles that has nutrients for the bacteria and then it is incubated (around 37 degrees)
  • there is an indicator at the bottom of the tub, the waste products of the bacteria will cause a change in colour of the indicator at the bottom -> is effectively a glorified pH detector
  • this process take around 18-24 hours
25
Q

What happens after a positive blood culture result occurs?

A
  • a confirmation of whether the blood cultures are positive or negative
  • generally: -ve = skin and soft tissue +ve = abdomen and urinary tract
26
Q

If possible, at what point should blood cultures be sent?

A
  • before administration of antibiotics -> with most bacteria there is a small window where you can test the cultures before giving antibiotics
  • ANTIBIOTICS IMMEDIATELY GIVEN IN PATIENTS WITH MENINGITIS OR MENINGOCOCCAL SEPTICAEMIA
27
Q

What is the point of the staphylococci coagulase test?

A
  • to distinguish between coagulase positive and staphylococci

o Coagulase POSITIVE = STAPHYLOCOCCUS AUREUS (the most important of coagulase positive staphylococci) -> coagulase is a virulence factor which helps Staphylococcus aureus to cause infection

o Coagulase NEGATIVE = common skin microbes -> don’t tend to cause infection unless there are some opportunistic circumstances (e.g. central lines, prosthetic joints)

28
Q

What are possible causes of diarrhoea?

A

o bacteria: common -> Salmonella (including S. typhi), Shigella, Campylobacter

uncommon -> E.Coli, C. difficile, Cholera

o parasites: Amoeba, Giardia, Cryptospordium (uncommon)

o viruses: generally associated with acute symptoms

29
Q

What 3 bacteria are commonly screeened in stool samples?

A

o Salmonella

o Shigella

o Campylobacter

  • any others have to be requested specifically
30
Q

Define Minimum Inhibitory Concentration (MIC).

A
  • the lowest amount of antibiotic required to inhibit the growth of bacteria in vitro
31
Q

When is a bacteria reported as being resistant?

A
  • if the MIC is above the breakpoint from the guidelines
  • breakpoint is the point in which the concentration is not going to be clinical possible
32
Q

What is the role of histopathologists?

A

o interested in tissues

  • biopsies
  • resection specimens
  • frozen sections -> when the patient is in surgery and an answer is needed
  • post-mortems
33
Q

What is the role of cytopathologists?

A

o interested in cells

  • smears -> cervical smears fro cancer is the most common
  • fine needle aspirates
34
Q

How are section obtained?

A
  • specimens are recieved -> must be properly labelled
  • fixed in formalin
  • embedded in paraffin wax and sections are cut
35
Q

What tests are carried out on sections in histopathology?

A
  • stained
  • identification of specific antigens -> immunohistochemistry
  • molecular tests
  • microscopy
36
Q

Which part of antibodies are variable and constant?

A
  • constant = Fc
  • variable = Fab
37
Q

What can be conjugated to antibodies in labs/for treatment?

A
  • enzymes
  • fluorescent probes
  • magnetic beads -> purification of cell types
  • drugs -> target particular tumours
38
Q

How are monoclonal antibodies produced?

A
  • normal B lymphocyte, are taken from the spleen, which is producing the antibody of interest and you FUSE IT with a myeloma cell line -> gives you a HYBRIDOMA
  • these cells have the ability to produce the antibody of interest -> as it is fused with a tumour cell, it can divide indefinitely to produce great numbers of thje antibodies
39
Q

What are the therapeutic uses of manufactured antibodies?

A
  • prophylactic protection against microbial infection
  • anti-cancer therapy
  • removal of T-cells from bone marrow grafts
  • block cytokine activity
40
Q

What are the diagnostic uses of manufactured antibodies?

A
  • tissue typing
  • blood group serology
  • immunoassays -> hormones, antibodies, antigens
  • immunodiagnosis -> infectious disease, autoimmunity, allergy, malignancy
41
Q

Where is immune complexes the biggest problem?

A
  • kidney function
42
Q

If immunodeficiency is suspected clinical, what tests would ran in an immunology lab?

A
  • serum immunoglobulin levels - serum electrophoresis, ELISA
  • specific antibodies - protein antigens or polysaccharides antigens
  • lymphocyte subsets
43
Q

Describe the natural history of HIV infection.

A
  • someone who hasn’t had HIV treatment

o BLUE - CD4 T cell count

o RED - viral load

  • primary infection - CD4 will initially go down and then it will go up again after a few weeks
  • viral remains controlled by the immune system for some time (clinical latency) -> viral load wont change that much during this time but CD4 will keep going down
  • when the CD4 count gets very low, the patient will start showing signs of opportunistic infection -> CD4 count continues to go down, the viral load will go up
  • a patient that has been diagnosed with HIV, you would monitor their CD4 count and measure their viral load
  • once their CD4 reaches a certain level you would start antiretroviral therapy
44
Q

What disease appear when CD4 starts to drop in HIV?

A
45
Q

Name a pneumonia only seen in immunocompromised.

A
  • Pneumocystic pneumonia

Y2 MCD (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions