Patch testing services and implementation in Australia
It is best practice that people with suspected dermatitis are patch tested comprehensively; to potentially identify the causes of their condition. Patch testing can be a time consuming, expensive and complex. It is time consuming for the dermatologist and nursing staff with patch preparation and product dilution. Allergens and patches are expensive.
In the past there have been two main methods of patch testing primarily used.
The first method involves stocking a range of commercially available allergens, of which there are more than 400 available for purchase.
Commercially available allergens
 Chemotechnique allergens |
 allergEAZE® allergens |
Buying a large assortment of individual allergen syringes can be costly, with each syringes often costing between than $35 and $100, and each having an expiry date of approximately 1.5 to 2 years (however some are shorter than this). Allergens kept past their use-by date may incur changes to their chemical makeup, potentially affecting results. Patients should also bring their own products from work and home for testing. In this situation the dermatologist decides what to test the individual to, according to their history. Allergens are applied to the patches, which are then placed on the patients’ back for two days. The patient is reviewed after a further two to four days, when a final interpretation (or reading) of the reactions is made.
The second method of patch testing involves a pre-packaged patch test system (True-Test®), which is simpler to apply but still relatively expensive. There are 36 allergens available on True-Test.® Sometimes these are used as screening tests. There is no option for selecting additional individual allergens. If the results are negative, but allergic contact dermatitis is strongly suspected on clinical grounds, then more extensive testing is indicated. There is evidence that suggests using these pre-prepared standardised tests correctly identifies allergens in only 28% of patients.
The cost of True-Test® can be found https://www.smartpractice.com/shop/category?cn=T.R.U.E.-TEST%C2%AE-Ready-to-Use-Patch-Test-Panels&id=508222&m=SPA.
There is now an additional patch testing option, The Contact Allergen Bank Australia (CABA). CABA was established by the Skin Health Institute, as a mail order patch test service. It aims to assist dermatologists provide comprehensive patch testing without having to purchase and prepare an exhaustive set of allergens in their rooms. Dermatologists have access to more than 400 allergens via this service. CABA involves patient specific allergens being mailed to the dermatologist, following the lodging of an order via the website www.patchcams.asn.au or by fax, phone or email.
This will be covered in Section 5.1 Contact Allergen Bank Australia
Setting up a patch testing service
Generally, patch testing occurs over 3 appointments over the course of 7-10 days. At the SHI, the first appointment is on Monday, the second appointment on Wednesday and the third appointment being Friday. Day 7 appointments are occassionally scheduled because some allergens characteristically take longer to react.
Some centres prefer to test over 4 appointments, where patients are initially assessed in a separate clinic, and then return on a separate occasion for the actual patch testing.
Individual allergens and series are obtained from the suppliers which are listed below. These companies have hundreds of allergens available, many different series as well as resources and information sheets.
When ordering allergens it is possible to have a mixture of allergens from both allergen suppliers as they often stock different concentrations/strength of allergens. There are more than 400 different allergens are commercially available.
Both companies have also created an “Australian Baseline Series” or an ‘ABS’ as it is commonly referred to. The series from each company may be slightly different due to different allergens or allergen concentrations they have available, and may have evolved with recent changes.
In addition to allergens, another essential item for patch testing is a computer program that will assist with allergen and clinic management. At the SHI, a program called PatchCams© has been developed over many years and is used in all patch testing clinics.
This will be covered in Section 5.2 Patchcams© a clinical management tool
Products needed to perform patch testing
There are several key items that are needed when making up the patches (Figure 1). At SHI, we suggest using:
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Figure 1 – Key Items for patch preparation
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Skin markers are also needed to mark the location of the patches. There are two types of commercially available skin markers available, one from Chemotechnique as shown in Figure 2 and another from Smart Practice.
Figure 2 – Examples of Chemotechnique skin markers
Figure 3 – Example of when a skin marker is used
A skin marker is used to mark the location of each disc on each patch (Figure 3). This is done when patches are first applied and then again when patches are removed. If a patient is having readings performed at day 7, it may be necessary to ask the patient to re-mark the existing lines, to ensure they are still visible on day 7. A cheap, disposable skin marker or surgical marker could be sent home with the patient.
Patch varieties available
There are two primary brands of patch testing products in Australia, allergEAZE® and Chemotechnique Diagnostics. Each company has a few different types of patch testing chambers available. Deciding which patch type to use is up to your organisation, depending on patient or or budget related factors. There are fabric styles as well as a newer waterproof style patch.
Informed consent and patch testing
Consent from the patient is required before patch testing is performed. At the SHI, all patients are given an in-depth information sheet and consent form before seeing the doctors, and before any patches are applied. This consent form describes the patch testing process and any potential risks and side-effects of the patch tests. The consent form is checked before any patches are applied to the patient. At the SHI, patients also need to consent to their information being entered into the electronic notes system called PatchCams©. Information is collected in accordance with the Privacy Act (Commonwealth Privacy Act 1988, The Health Records Act 2001 and Information Privacy Act 2000). See attachment for the Skin Health Institute’s consent form.
Medicare
Patch testing can be expensive. The cost is also dependent on how many patches are applied. When traditional patch testing is performed, normally a minimum of 6 patches or 60 allergens are tested, as there are 60 allergens in the ABS. The maximum number that can be applied is approximately 170 allergens or 17 patches.
Patch testing attracts a rebate under Medicare. The Item numbers which are used for patch testing are listed below.
104 Initial consultation
12012 < 26 allergens
12017 26-50 allergens
12021 51-75 allergens
12022 76-100 allergens
12024 100 plus allergens
105 Review appointment – patches off and final appointment
(Current November 2024)
Patients are generally charged an initial consultation fee (104) on day 1. This consultation takes longer than a standard dermatology consultation because an extensive history of skin exposures is ascertained. Thirty minutes is scheduled at the SHI. They are then charged an item number for the cost and preparation of patch tests, as listed above.
On the second and final appointment, patients are charged for review consultations (105). At the second appointment, if the patient has developed some reactions, additional enquiries may be directed to the workplace or to manufacturers of skin care products, or additional tests may be applied to clarify the positive reactions. The final consultation is often quite long, as it involves making a diagnosis of the patient’s skin condition and explaining this to the patient, as well as advice about treatment and management.
The billing sheet used at SHI can be viewed here.
Referring patients to the Skin Health Institute for patch testing
SHI receives referrals for patients from all parts of Australia. Our clinics primarily accept referrals from dermatologists, however some clinics will accept referrals from general practitioners and workplaces. To refer patients please send referral via the SHI website:
