Investigations

Question 1

When would you carry out a microbiological smear?

Answer 1

for testing for the presence of fungi or bacteria

Question 2

What microbiological investigations are there?

Answer 2

Smear
Plain Swab
Imprint culturte
Oral rinse

Question 3

When would you use a plain swab?

Answer 3

To detect for fungi, bacteria, HSV and VZV

Question 4

When would you carry out an imprint culture?

Answer 4

to determine bacteriological or fungal coloinisation of mucosa or surface of an IO appliance

Foam swab placed on site and sent to lab

Question 5

What do you use in a concentrated oral rinse?

Answer 5

10ml buffered phosphate saline

Question 6

How should tissue biopsied for immunofluorescence be sent to the lab?

Answer 6

should be sent on fresh ice or in michels solution

Question 7

what is vital staining?

Answer 7

Use of toluidine blue stain which is picked up by areas of abnormal mucosa, however some normal mucosa is also picked up. Used only as an adjcunt

Question 8

How do you perform the schirmer test?

Answer 8

This tests investigates lacrimal fluid flow
Placing a filter paper under the eyelid for 5 minutes.
Wetting of the paper of less than 5mm indicates reduced tear production

Question 9

when do you perform the schilling test?

Answer 9

to investigate B12 deficiency

looks at the amount of B12 excreted in the urine

Question 10

what is the purpose of a biopsy?

Answer 10

removal/sample of tissue for histopath assessment

Question 11

What colours are H and E staining?

Answer 11

Eosin stains pink

Haem: stains blue

Question 12

what structures does eosin stain?

Answer 12

keratin
muscle
Bone (un Ca)
collagen

Question 13

What structures does Haematoxylin stain?

Answer 13

Nuclei
cytoplasm
ground substance
Un Ca bone

Question 14

when do you use the PAS stain?

Answer 14

periodic acidic schiff stain

Fungi/mucins/glycogen

Question 15

when is the ziehl neelsen stain used?

Answer 15

Mycobacteria

Question 16

when is the congo red stain used?

Answer 16

amyloid protein

Question 17

what does immunohistochemistry look at? at when is it used?

Answer 17

monoclonal antibodies to antigens on cell surface. used to detect where primary site of tumour is

Question 18

what type of tissue preparation is needed for immunohistochem?

Answer 18

frozen or fixed

Question 19

what is the issue with frozen section tissues?

Answer 19

poor quality tissue

Question 20

when would you use frozen tissue?

Answer 20

when need rapid assessment of tissues

Question 21

What is the Paul bunnel test used for?

Answer 21

For diagnosis of IM via Detection of EBV

Question 22

What is used in the Paul bunnel test?

Answer 22

Patients serum is used to see if it causes agglutination of sheep erythrocytes. If EBV is present then the sheep erythrocytes will agglutinate

Question 23

What test has superseded the Paul bunnel test?

Answer 23

The mono spot test

Question 24

How does the mono spot test work?

Answer 24

It tests the patients serum for presence of heterophile antibodies by mixing horse red blood cells and the serum.

If EBV/CMV is present then the horse erythrocytes will agglutinate

Question 25

What other lab test can be used in IM?

Answer 25

Presence of atypical lymphocytes on blood smear

Question 26

What does heterophile antibodies mean in terms of lab testing?

Answer 26

They can cross react with antigens across species lines

Question 27

What is the problem with using the monospt test?

Answer 27

It is more of a screening method since the test may come back negative if in the first week of IM. So negative results should be repeated after a few days. Also in children aged less then 8 am EBV serology test should be performed if EBV is suspected

Question 28

When is the gram stain used?

Answer 28

Bacteria and some fungi

Question 29

What machine is used to free the tissues for frozen section?

Answer 29

Cryostat