Intradermal (intracutaneous) testing carries more decisions per site than a prick test: the starting dilution, the volume, the reading time and the criteria for a positive all vary with the indication. That makes the record matter more. This page summarizes what the AAAAI/ACAAI practice parameters say, and what an intradermal record should capture.[1]
When IDT is used
- IDT identifies more patients with lower skin-test sensitivity and is used when greater sensitivity is the main goal.[1]
- It is useful for evaluating anaphylaxis, particularly to drugs such as penicillin and to Hymenoptera venom.[1]
- For penicillin, full-strength reagents are applied by prick first; if those are negative, intradermal testing follows.[2]
- After sting anaphylaxis, intradermal venom tests generally start at 0.001 to 0.01 µg/mL and increase 10-fold until positive or until 1.0 µg/mL is reached.[3]
- Foods: not recommended. The 2008 parameter calls intradermal food tests potentially dangerous and overly sensitive, and NIAID says they should not be used to diagnose food allergy.[1][4]
What an IDT record adds to the SPT elements
Everything on a complete skin-test record applies (date, who tested, controls, wheal and erythema in mm, lots). Intradermal testing adds:[1]
| Element | Source and note |
|---|---|
| Method (intracutaneous) and the concentration or dilution for each allergen, for example 1:1,000 w/v or 1,000 AU/mL | 2008 parameter, form section |
| Wheal and erythema in mm for each site and for the histamine and diluent controls | 2008 parameter |
| Volume injected or initial bleb size | Both conventions appear in the sources (0.02–0.05 mL in 2008; a 0.02 mL injection raising a 3–5 mm bleb for antibiotics in 2022); recording which one was used is good practice[1][2] |
| For drug testing: the reagents used and the step at which the test turned positive | From the stepwise protocol in the 2022 drug parameter[2] |
The starting intradermal dose is generally 100- to 1,000-fold more dilute than the SPT concentration.[1] Recording the dilution on every site is what lets the next reader interpret the wheal.
Reading and criteria
The 2008 parameter says to read IDT 10 to 15 minutes after injection and to record both wheal and erythema in millimeters, with a diluent control and a weaker histamine control than the one used for SPT.[1]
| Indication | Criterion as stated in the source |
|---|---|
| General (2008) | "Any reaction larger than the negative control may indicate" specific IgE; 85% of surveyed board-certified allergists used ≥3 mm above the negative control[1] |
| Drugs (2022) | Wheal ≥3 mm over the negative control with flare ≥5 mm[2] |
| Venom (2016, North America/Europe) | Wheal 3–5 mm greater than the negative control with appropriate erythema, at ≤1 µg/mL[3] |
There is no single universal cut-off, so the record should state which criteria the practice applied. At a single 1:1,000 w/v dose IDT may be irritant, and reproducibility has been reported as poor, which is another reason to document the dilution and the controls for every site.[1]
Safety notes worth documenting
- Immediate systemic reactions are more common with intracutaneous tests than with prick tests; screening with prick tests first is a practical way to avoid them.[1]
- IDT is usually placed on the upper arm or volar forearm rather than the back, so that a tourniquet can be applied if systemic symptoms occur.[1]
- Penicillin skin testing should be done by trained personnel prepared to treat the very rare case of anaphylaxis.[2]
How Medora supports the intradermal workflow
- The allergist orders the panel in the patient's record; controls come first on the results sheet.
- The nurse photographs the panel and the photos are stored with the chart.
- Staff enter or confirm every value, wheal and erythema in millimeters, with who tested and when; nothing is recorded without a person.
- The allergist reviews and signs.
- Because Medora keeps one patient context, the clinician sees the skin-test results the nurse recorded (wheal sizes, controls, grades) alongside the drafted visit note.
- Medora Copilot has visit templates built for skin testing (SPT, intradermal and patch), so the testing visit note starts in allergy language.
Skin testing is priced per practice; it is not published, so talk to us. Medora Scribe (Copilot) is $99 per provider per month after a 14-day free trial, and no card is needed to start. See skin testing in Medora.
Frequently asked questions
When is an intradermal skin test read?
The 2008 AAAAI/ACAAI parameter says 10 to 15 minutes after injection, recording both wheal and erythema in millimeters. The UK venom convention reads at 20 minutes.
What should an intradermal test record include?
Everything on a skin prick test record, plus the method and the concentration or dilution for each allergen, wheal and erythema in mm for each site and for the controls, and, for drug testing, the reagents and the step at which the test turned positive.
Is intradermal testing used for foods?
No. The 2008 parameter says intradermal food tests are potentially dangerous and overly sensitive and are not recommended, and NIAID says they should not be used to diagnose food allergy.
Does Medora support intradermal testing?
Yes. Prick, intradermal and patch testing run in the same Medora workflow: the allergist orders, controls come first, photos are stored with the chart, staff enter or confirm every value, and the allergist signs.
Related guides
Sources
Last reviewed October 21, 2026. Summaries paraphrase the cited documents; read the originals before making clinical decisions. This page is for clinicians and practice teams, not patient instruction.
- Bernstein IL, Li JT, Bernstein DI, et al. Allergy diagnostic testing: an updated practice parameter. Ann Allergy Asthma Immunol. 2008;100(3 Suppl 3):S1–S148. www.aaaai.org
- Khan DA, Banerji A, Blumenthal KG, et al. Drug allergy: a 2022 practice parameter update. J Allergy Clin Immunol. 2022;150(6):1333–1393. doi.org
- Golden DBK, Demain J, Freeman T, et al. Stinging insect hypersensitivity: a practice parameter update 2016. Ann Allergy Asthma Immunol. 2017;118(1):28–54. doi.org
- NIAID-Sponsored Expert Panel (Boyce JA, et al.). Guidelines for the diagnosis and management of food allergy in the United States. J Allergy Clin Immunol. 2010;126(6 Suppl):S1–S58. pmc.ncbi.nlm.nih.gov