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Completed

NCT Number: NCT02527187

Determination of the Sensitivity and Specificity of Prick Test Betula Verrucosa

The main objective is to evaluate the concentration of allergen extract of Betula verrucosa that elicit a papule equivalent to that produced by a solution of histamine dihydrochloride 10 mg / ml in size.

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Key information

Conditions

Immune System Diseases

Age range

5 year–70 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

Hospital Lucus Augusti

Lugo, Galicia, 27003, Spain

About this study

Open, prospective, unblinded and non-randomized biological assay. Each patient was tested with four concentrations of allergen and with a histamine and saline solution as positive and negative controls, respectively.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

General inclusion criteria for both groups:

  • Positive skin prick test with the positive control (Histamine HCl at 10 mg/mL). The length of the largest diameter of the wheal induced by this control should be ≥ 3 mm.
  • Negative skin prick test with the negative control. The length of the largest diameter of the wheal induced by this control should be < 3 mm.
  • All ages and both genders.

For the group of patients CH+ (true positive to Betula verrucosa): All these patients had a previous diagnosis of allergy to the birch pollen:

  • A positive case history with inhalant allergy related to exposure to birch pollen.
  • A positive skin prick test (mean wheal diameter ≥ 3 mm) when tested with a biologically standardized extract prepared from birch pollen. This preparation, from another manufacturer, was the one used in the routine in the Hospital.
  • Positive test for specific IgE (CAP value > 0.35 IU/mL). For the group of patients CH- (true negative to Betula verrucosa): All these patients had a previous diagnosis of allergy to agents unrelated to birch pollen.
  • A negative case history with inhalant allergy related to exposure to birch pollen or to pollen with known cross-reactivity with the birch pollen. These patients could be allergic to other pollen or other allergens, such mites.
  • A negative prick test (largest diameter of the wheal ≥ 3 mm) when tested with a standardized extract prepared from the allergen source in question.
  • A negative test for specific IgE (CAP value < 0.35 IU/mL) to birch pollen or to pollen with known cross-reactivity with birch pollen: Corylus avellana, Quercus verrucosa, Fagus sylvatica, Castanea satavia, Carpinus betelus and Alnus glutinosa.

Exclusion criteria

for both groups:

  • Patients that were using drugs that may interfere with the skin prick tests.
  • Patients using the following drugs 24 hours before the test: theophylline, systemic corticosteroids.
  • Patients in which the largest diameter of the wheal induced by the positive control was < 3 mm.
  • Patients in which the largest diameter of the wheal induced by the negative control was ≥ 3 mm.
  • Pregnancy, dermographism, atopic dermatitis (locally at the test site), urticaria.
  • Patients who suffer disease in which the use of adrenaline is not allowed.
  • Patients with any severe psychiatric disease.

For the patients CH+:

  • Patients that received or are treated with immunotherapy with an allergenic extract of birch pollen and/or with allergen extracts with known cross-reactivity to birch pollen (Corylus avellana, Quercus verrucosa, Fagus sylvatica, Castanea satavia, Carpinus betelus and Alnus glutinosa).

For the patients CH-:

  • Patients sensitized to pollen with demonstrated cross-reactivity with the pollen of Betula verrucosa. These pollen included Corylus avellana, Quercus verrucosa, Fagus sylvatica, Castanea satavia, Carpinus betelus and Alnus glutinosa.

Treatment and study plan

10 HEP/mL Betula verrucosa allergen extract

Biological

The investigational product contained 10 HEP/mL Betula verrucosa allergen extract and was tested by administration onto skin. The test was carried out on the forearm following prick test technique.

25 HEP/mL Betula verrucosa allergen extract

Biological

The investigational product contained 25 HEP/mL Betula verrucosa allergen extract and was tested by administration onto skin. The test was carried out on the forearm following prick test technique.

50 HEP/mL Betula verrucosa allergen extract

Biological

The investigational product contained 50 HEP/mL Betula verrucosa allergen extract and was tested by administration onto skin. The test was carried out on the forearm following prick test technique.

100 HEP/mL Betula verrucosa allergen extract

Biological

The investigational product contained 100 HEP/mL Betula verrucosa allergen extract and was tested by administration onto skin. The test was carried out on the forearm following prick test technique.

Primary outcomes

  1. Sensitivity for 100 HEP/mL

    Time frame: 1 hour

    Sensitivity for 100 HEP/mL concentration of the pollen of Betula verrucosa allergen extract used in skin prick test.

    It is the proportion of positives that are correctly identified by the test.

    Sensitivity: True positives/Total disease

  2. Sensitivity for 50 HEP/mL

    Time frame: 1 hour

    Sensitivity for 50 HEP/mL concentration of the pollen of Betula verrucosa allergen extract used in skin prick test.

    It is the proportion of positives that are correctly identified by the test.

    Sensitivity: True positives/Total disease

  3. Sensitivity for 25 HEP/mL

    Time frame: 1 hour

    Sensitivity for 25 HEP/mL concentration of the pollen of Betula verrucosa allergen extract used in skin prick test.

    It is the proportion of positives that are correctly identified by the test.

    Sensitivity: True positives/Total disease

  4. Sensitivity for 10 HEP/mL

    Time frame: 1 hour

    Sensitivity for 10 HEP/mL concentration of the pollen of Betula verrucosa allergen extract used in skin prick test.

    It is the proportion of positives that are correctly identified by the test.

    Sensitivity: True positives/Total disease

  5. Specificity for 100 HEP/mL

    Time frame: 1 hour

    Specificity for 100 HEP/mL concentrations of the pollen of Betula verrucosa allergen extract used in skin prick test.

    It is the proportion of negatives that are correctly identified by the test.

    Specificity: True negatives/Total no disease.

  6. Specificity for 50 HEP/mL

    Time frame: 1 hour

    Specificity for 50 HEP/mL concentrations of the pollen of Betula verrucosa allergen extract used in skin prick test.

    It is the proportion of negatives that are correctly identified by the test.

    Specificity: True negatives/Total no disease.

  7. Specificity for 25 HEP/mL

    Time frame: 1 hour

    Specificity for 25 HEP/mL concentrations of the pollen of Betula verrucosa allergen extract used in skin prick test.

    It is the proportion of negatives that are correctly identified by the test.

    Specificity: True negatives/Total no disease.

  8. Specificity for 10 HEP/mL

    Time frame: 1 hour

    Specificity for 10 HEP/mL concentrations of the pollen of Betula verrucosa allergen extract used in skin prick test.

    It is the proportion of negatives that are correctly identified by the test.

    Specificity: True negatives/Total no disease.

Sponsors and collaborators

Lead sponsor

Inmunotek S.L.

Industry

Registry information

Official study title

Extract Allergen From Betula Verrucosa. Test Sensitivity and Specificity of Diagnostic in Prick Test Preparation.

Acronym: T502

Important dates

Study start
2015
Primary completion
2016
Study completion
2016
First posted
Aug 18, 2015
Registry last updated
May 5, 2022

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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