Indications and Usage
Indications:
TRUE Test™ is indicated primarily for the
diagnosis of contact dermatitis in patients whose
histories suggest sensitization to one or more
of the substances in the test panel. To exclude
sensitization as a possible etiology, TRUE Test™
may also be used adjunctively to evaluate other
eczemas (atopic seborrhoeic, venous, palmar and
plantar hyperkeratotic eczema, vesiculosis or
neurodermatitis) and other dermatological diseases,
such as leg ulcers and psoriasis that do not heal.
A clinical history that suggests a contact allergy
should be confirmed with a patch test.
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Description
TRUE Test™ is a ready-to-use patch test
indicated for the diagnosis of allergic contact
dermatitis. It consists of 24 of the most common
allergens; nickel sulphate, wool alcohols, neomycin
sulfate, potassium dichromate, caine mix, fragrance
mix, colophony, epoxy resin, quinoline mix, balsam
of Peru, ethylenediamine dihydrochloride, cobalt
chloride, p-tert-butylphenol formaldehyde resin,
paraben mix, carba mix, black rubber mix, Cl+Me-isothiazolinone
(Kathon CG), quaternium-15, mercapto benzothiazole,
p-phenylenediamine, formaldehyde, mercapto mix,
thiomersal and thiuram mix.
The test consists of 2 pieces of surgical tape with
24 polyester patches which are coated with a film containing
a specific allergen or allergen mix.
Due to the instability of some allergens on panel 2,
a desiccant paper has been included in the pouch.
This is to assure stability throughout the shelf-life.
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Clinical Pharmacology
A positive response to the patch test is a classical
delayed hypersensitivity reaction (type IV), which
can appear within 6-96 hours after exposure.
The cell-mediated response involves the Langerhans’
cell and T-lymphocytes, which interact and produce
lymphokines. These lymphokines then form lymphocyte
clones with trigger macrophages to cause a cutaneous
inflammation.
Clinical signs of a positive contact dermatitis reaction
are: erythema, edema, papules, vesicles and a
palpable dermal inflammatory infiltrate at the
test area.
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Contraindications and Warnings
CONTRAINDICATIONS
The minor amount of allergen on each TRUE Test™
patch, which penetrates the skin, will rarely
induce a flare-up of dermatitis. In the case of
extensive ongoing contact dermatitis, however,
the test should not be applied since it may provoke
an intensified reaction on both the present and
previously affected sites and may also cause a
false-positive test result.
WARNINGS
Occasionally sensitization to a substance on the
test panel may occur with patch testing. A test
reaction that appears later than 7 days after
application of the test may be a sign of contact
sensitization.
Excited skin syndrome (angry back) is a state
of hyperactivity induced by dermatitis on other
parts of the body or by a strong positive skin-test
reaction. Therefore, test results should be evaluated
carefully in patients with multiple positive concomitant
patch test results. To determine which reactions
are false-positive, retesting at a later date
may be necessary.
A potential carcinogenic risk exists with nickel sulfate,
potassium dichromate, cobalt chloride, epoxy resin
and thiuram mix. However, due to the low content
of allergen and brief contact period (48 hours),
there is no reason to suspect that a carcinogenic
risk exists with TRUE Test™.
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Precautions and Adverse Reactions
PRECAUTIONS
General:
TRUE Test™ may be administered throughout
the year. However, in summertime excessive sweating
and exposure of the test site to the sun are to
be avoided.
TRUE Test™ should be applied only, to healthy
skin that is free of acne, scars, dermatitis, or any
other condition that may interfere with test results.
Since steroids may suppress a positive test reaction,
use of topical steroids on the test site or oral steroids
(equivalent to 10 mg prednisolone) should be discontinued
for at least two weeks prior to testing.
If a severe patch test reaction develops, the patient
may be treated with a topical corticosteroid preparation
or, in rare cases, a systemic corticosteroid.
Pregnancy and pediatric use:
The test is not recommended to be applied to the skin
of pregnant and breast-feeding women nor infants.
ADVERSE REACTIONS
General:
A flare-up of dermatitis may be observed when testing
during an active phase of dermatitis. Sensitization
(see warnings).
Local:
A positive test reaction usually disappears within
1-2 weeks. On rare occasions, test reactions may
persist for a month, leaving an area of transient
hypopigmentation. Irritation caused by the surgical
tape adhesive may occur, but usually disappears
rapidly.
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Supply and Storage
HOW SUPPLIED
TRUE Test™ is supplied in multipack cartons
of 10 Panel 1 and 10 Panel 2.
Storage:
Store at +2 to +8ºC. The expiry date is stated
on the package.
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