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Updated: Aug 11, 2026
21:16
An In Vitro Skin Irritation Test (SIT) using the EpiDerm Reconstructed Human Epidermal (RHE) Model
Published on: July 13, 2009
Six-hour versus 48-hour patch testing with varying concentrations of potassium dichromate
M K Kosann1, R R Brancaccio, J L Shupack
1New York University Ronald O. Perelman Department of Dermatology, New York University Medical Center, New York, NY 10016, USA.
Summary
Shorter, 6-hour patch testing for potassium dichromate (K2Cr2O7) requires higher allergen concentrations. Significant individual variability in reactions suggests 6-hour patch tests are not suitable for routine use.
Area of Science:
- Dermatology
- Allergy Testing
- Toxicology
Background:
- Standard patch testing uses 48-hour contact times.
- Potassium dichromate (K2Cr2O7) is a common contact allergen.
- Optimizing allergen exposure duration is crucial for accurate diagnosis.
Purpose of the Study:
- To investigate the feasibility of using shorter, 6-hour patch contact times.
- To compare reactions to K2Cr2O7 at 6-hour versus 48-hour patch test durations.
- To determine if shorter patch test durations are viable for routine clinical use.
Main Methods:
- 11 subjects received K2Cr2O7 patches at varying concentrations for 6 and 48 hours.
- Minimum elicitation thresholds (METs) were determined for both exposure durations.
- Ratios of 6-hour MET to 48-hour MET were calculated to assess interindividual variability.
Main Results:
- All subjects reacted to K2Cr2O7 at 48 hours.
- 64% of subjects (7/11) reacted at 6 hours.
- Higher K2Cr2O7 concentrations were needed for 6-hour reactions compared to 48-hour reactions.
Conclusions:
- A higher allergen concentration is necessary for 6-hour patch tests.
- Significant interindividual variability in MET ratios was observed.
- 6-hour patch testing with K2Cr2O7 is not recommended for routine use due to variability.
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