Intradermal testing Flashcards

1
Q

Tests of cell-mediated immunity

A

Allergenic extracts are injected intradermally & the sites are monitored for allergic reactions

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2
Q

Allergens

A

Substance that causes an allergic reaction

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3
Q

Urticaria

A

Hives

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4
Q

Wheals

A

Swelling on the surface of the skin

Red welts

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5
Q

Angioedema

A

Edema of the dermis & subcutaneous tissues

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6
Q

What antibody, leukocyte, and cells are active during allergic reactions

A

IgE, basophils, and mast cells

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7
Q

What is intradermal testing?

A

Tests of cell-mediated immunity

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8
Q

What species do we do intradermal testing?

A

Dogs

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9
Q

Can dogs have allergies to more than one allergen?

A

Yes

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10
Q

What are the allergens based on?

A

Geography and patient history

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11
Q

What testing has not been vaildated yet?

A

Intradermal testing for food allergies

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12
Q

What are reactions triggered by?

A

Basophils and/or mast cells releasing histamine-containing granule that invoke an inflammatory response

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13
Q

How do you prepare a dog for intradermal testing?

A

Shave the hair on the lateral thorax

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14
Q

What do you use to mark injection sites?

A

Felt-tip marker

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15
Q

How far apart should the injection sites be?

A

2cm

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16
Q

What gauge needle do you use to inject the specifically selected antigen?

A

26 gauge needle

0.05mLs of specifically selected antigen

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17
Q

When do you evaluate the injection sites?

A

15 and 30 minutes

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18
Q

How do you grade the sites?

A

Based on the controls

Measure the diameter of the wheal

19
Q

What is the positive control?

A

Histamine

20
Q

What is the negative contorl?

A

Saline

21
Q

What are reasons for false negative reactions?

A
Subcutaneous injection
Too little antigen
Drug interference 
Anergy
Inherent host factors
Endoparasitism or ectoparasitism
Off-season testing
Histamine
22
Q

False negative reactions: Drug interference

A
Glucocorticoids
Antihistamines
Tranquilizers
Progetational compoinds
Drugs that lower blood pressure
23
Q

False negative reactions: Anergy

A

Testing during peak hypersensitivity reaction

24
Q

False negative reactions: Off-season testing

A

Testing more than 1-2 months after clinical signs have disappeared

25
Q

False negative reactions: Histamine

A

Hyporeactivity

26
Q

What are the reasons for false positive reaction?

A
Irritant Test allergens
Contaminated test allergens
Skin-sensitizing antibody only
Poor technique
Substance that cause nonimmunologic histamine release
Irritable skin 
Dermatographism
Mitogenic allergen
27
Q

False positive reactions: Irritant test allergens

A

Contain glycerin, house dust, feathers, wool, old and all food preparations

28
Q

False positive reactions: Contaminated test allergens

A

Bacteria or fungi

29
Q

False positive reactions: Poor technique

A

Traumatic placement of the needle
Dull or burred needle
Too large volume injected
Air injected

30
Q

False positive reactions: Substances that cause nonimmunologic histamine release

A

Narcotics

31
Q

False positive reactions: Irritable skin

A

Large reactions seen to all infected substances

32
Q

What does a positive reaction look like?

A

A raised welt that indicates the animal is allergic to the antigen

33
Q

What do hypersensitive reactions look like?

A

Urticaria (hives), wheals, or angioedema

34
Q

Why do hypersensitivity reactions occur

A

The dog has allergies to more than one allergen

35
Q

What are common allergies?

A

Grass, trees, pollen, molds, dust

36
Q

What is the goal of intradermal testing?

A

To create allergy shots to desensitize the animal to the allergens

37
Q

What is the ELISA test developed for allergies?

A

ALLERCEPT

38
Q

What does ALLERCEPT determine?

A

The specific IgE antibodies in dogs, cats and horses

39
Q

What does ALLERCEPT test for?

A

Grasses, trees, weeds, mites, insects, and fungi

40
Q

How do you do the tuberculin test?

A

Inject tuberculin intradermally at a site in cervical region or skin fold at the base of the tail

41
Q

What animals is the tuberculin test commonly performed on?

A

Cattle and primates

42
Q

What do animals with Mycobacterium spp develop?

A

A delayed hypersensitivity reaction to the organism tuberculin

43
Q

Why is it a delayed reaction?

A

Because T lymphocytes must migrate to the foreign antigen injected

44
Q

What does the tuberculin test actually test for?

A

Mycobacterium