Standardizing the Delivery of 20 μL of Hapten during Patch Testing

Abstract

Background

The current method for patch test tray assembly requires hand dispensing a small volume of hapten onto chambers. Because of human error, this technique produces inaccurate and inconsistent results. The recommended volume of hapten for patch testing using Finn Chambers is 20 μL.

Objective

The aims of this study were to create a device that standardizes the delivery of 20 μL and to compare it with the current hand dispensing technique.

Materials and Methods

A device, named the Revolution, was created using the SolidWorks program. Five nurses in our Contact Dermatitis Clinic were asked to load 10 Finn Chambers using the current technique and also using the Revolution. Assembly time, volume of petrolatum, and accuracy of placement were measured. After the 3 trials, the nurses completed a survey on the 2 methods.

Results

The amount of petrolatum dispensed using the current technique ranged from 16 to 85 μL, with an average amount of 41.39 μL. The Revolution design dispensed an average of 19.78 μL.

Conclusions

The current hand dispensing technique does not allow for accurate and consistent dispensing of 20 μL for patch testing. In contrast, the Revolution is an accurate and consistent device that can help standardize the patch testing method.