Allergy, Hypersensitivity, Immediate, Ig-E Mediated Food
Conditions
Keywords
Allergy skin testing, Skin prick test, Multi-head skin test device, Device comparison, Diagnostic accuracy, Sensitivity and specificity, Intra-device variability
Brief summary
This clinical study, titled "Head-to-Head Comparison Study between Different FDA Registered Allergy Skin Test Applicators," aims to compare the reliability and clinical performance of three skin prick test (SPT) devices: Allertest™ Multiple Skin Test Applicator, Lincoln Multi-Test II, and Greer Skintestor OMNI Applicator. The primary objective is to evaluate the consistency and accuracy of these devices in allergy testing.
Detailed description
Background and Rationale: Percutaneous allergy skin testing remains the gold standard diagnostic method for IgE-mediated allergic disease. Multiple-head skin prick test (SPT) devices enable simultaneous application of multiple allergens, improving testing efficiency while potentially reducing patient discomfort. However, significant inter-device variability exists among commercially available devices, with important implications for diagnostic accuracy and clinical interpretation. Intra-device variability-inconsistent responses across individual test heads within a single device-represents a particularly concerning phenomenon that may lead to physician misinterpretation and potentially inappropriate treatment decisions. Such variability can be attributed to manufacturing factors including tooling mold precision, molding equipment quality, and process controls during production. Prior research has demonstrated that devices with lower finished product variability exhibit improved clinical performance characterized by reduced false-positive reactions to negative controls. Study Design: This prospective, single-visit, head-to-head device comparison study employed a paired design in which each participant served as their own control, receiving testing with two devices simultaneously-one device applied to each forearm. This within-subject design minimizes inter-individual variability and provides robust comparative data. Participants were allocated into two comparison groups based on device head configuration: a 10-head device comparison (n=13) and an 8-head device comparison (n=17). Device assignment to right versus left forearm was randomized. Testing personnel were blinded to solution contents (histamine versus glycerin) during application, and a separate evaluator blinded to device assignment recorded wheal measurements. Study Procedures: All testing was performed by trained personnel in accordance with standard percutaneous skin testing protocols. Histamine dihydrochloride (1 mg/mL; ALK-Abello) served as the positive control and glycerin solution (ALK-Abello) served as the negative control. Devices were applied to the volar forearm surfaces with standardized pressure and technique. Test sites were maintained at least 2 cm apart to prevent cross-contamination between histamine and glycerin reactions. Wheal measurements were obtained 15-20 minutes post-application using the mean diameter method (average of longest diameter and its perpendicular midpoint), consistent with established international guidelines. Pain assessment was performed immediately following device application. Statistical Considerations: Paired comparisons between devices were analyzed using Wilcoxon signed-rank tests for continuous variables and McNemar's test for dichotomous outcomes. Intra-device variability was quantified using the coefficient of variation (CV) calculated across test heads, with lower values indicating greater consistency. Exact binomial (Clopper-Pearson) confidence intervals were calculated for sensitivity and specificity estimates. Statistical significance was set at α=0.05 (two-sided). Clinical Significance: This study addresses an important knowledge gap regarding comparative clinical performance of multi-head allergy testing devices. Results provide evidence-based data to inform device selection decisions that may impact diagnostic accuracy, patient comfort, and reliability of allergen identification in clinical allergy practice.
Interventions
DEVICEAllerTest-10 Multi-Head Skin Test Device
FDA-cleared 10-head percutaneous skin test applicator manufactured by MedScience Research Group, Inc., distributed by ALK Abello, Inc. The device consists of 10 individual test heads arranged in a linear array, each with a standardized needle length designed to penetrate the epidermis without drawing blood. Applied with standardized pressure for simultaneous delivery of 10 test substances (histamine and glycerin controls in this study). Single-use, disposable device.
DEVICESkintestor OMNI Multi-Head Skin Test Device
FDA-cleared 10-head percutaneous skin test applicator manufactured by Greer Laboratories, Inc. The device consists of 10 individual test heads arranged in a linear array for simultaneous application of multiple allergens and controls. Applied with standardized pressure for delivery of histamine and glycerin controls in this study. Single-use, disposable device.
DEVICEMulti-Test II Multi-Head Skin Test Device
FDA-cleared 8-head percutaneous skin test applicator manufactured by Lincoln Diagnostics, Inc. The device consists of 8 individual test heads arranged in a linear array for simultaneous application of multiple allergens and controls. Applied with standardized pressure for delivery of histamine and glycerin controls in this study. Single-use, disposable device.
DEVICEAllerTest-8 Multi-Head Skin Test Device
FDA-cleared 8-head percutaneous skin test applicator manufactured by MedScience Research Group, Inc., distributed by ALK Abello, Inc. The device consists of 8 individual test heads arranged in a linear array, each with a standardized needle length designed to penetrate the epidermis without drawing blood. Applied with standardized pressure for simultaneous delivery of 8 test substances (histamine and glycerin controls in this study). Single-use, disposable device.
Sponsors
QHSLab, Inc.
ALK-Abelló A/S
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
DIAGNOSTIC
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Intervention model description
This study employed a paired comparison design with each participant serving as their own control. Participants were assigned to one of two device comparison groups: (1) 10-head device comparison (AllerTest-10 vs. Skintestor OMNI, n=13), or (2) 8-head device comparison (AllerTest-8 vs. Multi-Test II, n=17). Within each comparison group, both devices were applied simultaneously-one to each forearm-with randomized left/right assignment. Each device was loaded with standardized histamine positive control and glycerin negative control. This within-subject design eliminates inter-subject variability in skin reactivity, providing robust paired comparisons of device performance on pain perception, control accuracy (sensitivity/specificity), and intra-device consistency.
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
* Patients will be entered into this study only if they meet all of the following criteria: 1. Written and signed informed consent obtained before starting any protocol-specific procedures. 2. Subjects willing to withhold antihistamines, Leukotriene antagonists and H2 antagonists for at least 1 week before testing to avoid masking the histamine reactions on the skin. 3. Male or female between 18 to 60 65 years, inclusive. 4. Ability to comply with the study procedures and visit schedule.
Exclusion criteria
* Patients will NOT be entered into this study if they meet any of the following criteria: 1. Anaphylactic reaction (constitutional) after the previous skin test with the same allergen 2. Acute fever 3. Systemic disease with acute manifestation or decompensation 4. Abnormal skin condition in the area to be tested (such as eczema sunburn condition after sunbathing) 5. Pregnancy 6. Presence of dermatographism, severe atopic dermatitis, or use of tricyclic antidepressants. 7. Current use of beta-blockers 8. Known hypersensitivity to any component of the test solutions (histamine or glycerin). 9. Participation in another clinical study within 30 days before enrollment. Participation in another clinical study within 30 days before enrollment.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Pain Assessment Using Visual Analog Scale (VAS) | Immediately after device application (within 1 minute of skin test procedure) | Procedural pain assessed immediately after device application using a 0-10 Visual Analog Scale (VAS), where 0 represents no pain and 10 represents unspeakable pain. Lower scores indicate less pain and better tolerability. |
| Sensitivity (Histamine Positive Control Performance) | 15 minutes after device application | Proportion of histamine control sites producing wheal ≥3 mm diameter at 15 minutes post-application. A wheal of ≥3 mm is the standard threshold for a positive allergic reaction. Higher sensitivity indicates better device performance in reliably eliciting positive control responses. Calculated as: (number of histamine sites with wheal ≥3 mm) / (total number of histamine sites tested) × 100%. |
| Specificity (Glycerin Negative Control Performance) | 15 minutes after device application | Proportion of glycerin control sites producing wheal \<3 mm diameter at 15 minutes post-application. Glycerin should not produce a wheal response; a result \<3 mm confirms appropriate negative control performance and absence of non-specific mechanical irritation. Higher specificity indicates better device performance. Calculated as: (number of glycerin sites with wheal \<3 mm) / (total number of glycerin sites tested) × 100%. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Intra-Device Variability | 15 minutes after device application | Coefficient of variation (CV) of histamine wheal sizes across all test heads within each device, calculated as CV = (standard deviation / mean) × 100%. Lower CV values indicate greater consistency and precision across test heads within the same device. This measure reflects the reliability of allergen delivery across multiple heads of a single device application. |
| Mean Histamine Wheal Size | 15 minutes after device application | Mean diameter (in millimeters) of wheals produced by histamine positive control across all test heads of each device. Wheal diameter measured using the mean diameter method (average of longest diameter and its perpendicular midpoint). Larger wheals indicate stronger positive control response. |
| Mean Glycerin Wheal Size | 15 minutes after device application | Mean diameter (in millimeters) of wheals produced by glycerin negative control across all test heads of each device. Wheal diameter measured using the mean diameter method (average of longest diameter and its perpendicular midpoint). Smaller measurements (ideally 0 mm) indicate appropriate negative control performance with minimal non-specific irritation. |
| Proportion of Subjects with Clinically Significant Pain | Immediately after device application (within 1 minute of skin test procedure) | Proportion of participants experiencing more than mild pain, defined as a score greater than 4 on the Visual Analog Scale (VAS) for pain. The VAS ranges from 0 (no pain) to 10 (unspeakable pain), with higher scores indicating worse pain. A threshold of \>4 represents approximately 40% of the scale and indicates clinically meaningful discomfort. Lower percentages indicate better device tolerability across the study population. Reported as percentage with 95% exact binomial confidence intervals. |
Countries
United States
Outcome results
None listed