Immediate Hypersensitivity Skin Testing Flashcards
Immediate Hypersensitivity Skin Testing is what Type on the Gel and Combs scale?
Type I
How long does it take for a reaction to occur with Immediate skin testing?
15 Minutes
What are the precautions for Immediate Skin Testing?
- Beta Blockers
- Certain Chronic Medical Conditions
What are the contraindications for Immediate Skin Testing?
- Severe asthma attack in the past two weeks
- Antihistimes
- Pregnancy
- Longtime Steroid Use
What are the two types of Immediate Skin Testing?
- Prick
- Intradermal
What are the advantages of Prick Skin Testing?
- Safer than ID
- Minimal systemic absorption
- Faster
- Less tedious for the technician
- Less discomfort for the patient
What are the disadvantages of prick skin testing?
- Chance of Cross Contamination
- Chance of Cross Reaction
What is the strength of the positive control for prick skin testing?
2.75 mg/ml
What is used for the negative control for prick skin testing?
- HSA
- Glycerin
What are the strengths of the extracts used for prick skin testing?
- 10,000 - 20,000 PNU/mL
- 1:10 or 1:20 W/V
What are the locations used for prick skin testing?
- Forearm
- Back
What are the two types of devices used for prick skin testing?
- Quintip
- Dermaprick
When placing prick skin testing how far apart must each prick be placed?
1 inch
Once a Prick skin test has been placed how long must one wait to read the test?
15 Minutes
When reading the prick skin test it should always be measured ____________ X __________
Wheal X Flare
A prick test with a diameter greater than _______ is considered positive?
> 3 mm
What would cause a false positive for immediate Hypersensitivity Skin Testing?
- Technician Error
- Excessive strength of antigen
- Excessive dose of antigen
- Cross contamination
- Dermographic Patient
What would cause a false negative for immediate Hypersensitivity Skin Testing?
- Improperly prepared/stored extract
- bottle/label contents mismatched
- out dated extracts
- Patient took antihistamines
- Technician error
- Improper placement
- Intrinsic patient factors
- leathery skin
What are the advantages of Intradermal skin testing?
- More Sensitive
- Less chance of cross contamination
What are the disadvantages of Intradermal skin testing?
- More dangerous
- Causes more discomfort to the patient
- More tedious for the technician
- More irritant/ non-specific reactions
What are the extract strengths used for ID testing?
- 100 - 1,000 PNU/ml
- 1:500 or 1:1000 W/V
What is the strength of the positive control for ID testing?
0.275mg/ml
What is the positive control used for ID and prick skin testing?
Histamine
What is the negative control used for intradermal testing?
- Saline with HSA
- Saline with Phenol
