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DRUG ALLERGY SCREENING TESTS (BY IMMUNO - EIA)
Allergy
Report in 72Hrs
At Home
No Fasting Required
Details
Detects allergy to common drugs.
₹2,516₹3,594
30% OFF
Drug Allergy Screening Tests (By Immuno-EIA)
- Why is it done?
- Test Purpose: This immunoassay detects drug-specific IgE antibodies in serum using enzyme immunoassay (EIA) technology to identify hypersensitivity reactions to medications and pharmaceutical agents.
- Primary Indications: Patients with history of adverse drug reactions, allergic symptoms during or after medication administration, need for safe antibiotic selection, evaluation of penicillin/beta-lactam allergy, assessment of drug hypersensitivity prior to treatment initiation.
- Clinical Situations: Evaluation during acute allergic reaction has subsided, pre-operative assessment, confirmation of suspected IgE-mediated drug allergy, identification of safe alternative medications, occupational exposures requiring immunological profiling.
- Normal Range
- Reference Values: Negative/Non-detectable (typically <0.10-0.35 kUA/L depending on assay platform and specific drug antigen).
- Units of Measurement: kUA/L (kilo units of allergen per liter) or kIU/L (kilo international units per liter).
- Interpretation Categories: • Negative (Class 0): <0.10 kUA/L - No specific IgE antibodies detected • Borderline/Equivocal (Class 1): 0.10-0.35 kUA/L - Minimal sensitization • Weak Positive (Class 2): 0.35-0.70 kUA/L - Low-level sensitization • Moderate Positive (Class 3): 0.70-3.50 kUA/L - Clinically significant sensitization • Strong Positive (Class 4-6): >3.50 kUA/L - High probability of IgE-mediated allergy
- What Normal Means: Absence of detectable drug-specific IgE antibodies; low probability of immediate hypersensitivity reaction to the tested drug.
- What Abnormal Means: Presence of detectable drug-specific IgE antibodies indicating sensitization; increased risk of IgE-mediated allergic reaction (anaphylaxis, urticaria, angioedema).
- Interpretation
- Negative Result (<0.10 kUA/L): No specific IgE antibodies detected to the tested drug. Generally indicates low risk of IgE-mediated hypersensitivity; however, does not completely exclude non-IgE mediated reactions (T-cell, delayed reactions). Alternative antibiotics or medications may be safely considered.
- Positive Result (>0.35 kUA/L): Drug-specific IgE antibodies detected. Indicates sensitization and significant risk of immediate hypersensitivity reaction. Drug should generally be avoided unless absolutely essential and only with appropriate medical supervision and emergency medications available.
- Borderline Result (0.10-0.35 kUA/L): Equivocal findings requiring correlation with clinical history. May represent minimal sensitization or laboratory edge effect. Clinical judgment and additional history recommended.
- Factors Affecting Interpretation: • Timing of serum collection (IgE can be present weeks to months after sensitization) • Cross-reactivity between related drug compounds (e.g., beta-lactams) • Recent immunotherapy or immunosuppression affecting antibody levels • Nature of initial allergic reaction (severity and type) • Patient's immunological status and age • Specificity of the drug hapten used in the assay
- Clinical Significance: Positive results correlate with approximately 50-80% probability of IgE-mediated reaction upon drug re-exposure. Sensitivity varies by drug class (highest for penicillins ~90%, lower for other drugs ~40-60%). Negative results have high negative predictive value (95-99%) for IgE-mediated reactions but do not exclude delayed hypersensitivity.
- Associated Organs
- Primary Organ Systems Involved: • Respiratory System: Bronchospasm, laryngeal edema, respiratory distress • Cardiovascular System: Hypotension, tachycardia, arrhythmias, anaphylactic shock • Integumentary System: Urticaria, pruritus, angioedema, contact dermatitis • Gastrointestinal System: Abdominal pain, nausea, vomiting, diarrhea • Central Nervous System: Dizziness, syncope, anxiety, confusion
- Associated Diseases and Conditions: • IgE-mediated drug hypersensitivity • Anaphylaxis • Acute urticaria and angioedema • Acute respiratory distress syndrome • Stevens-Johnson Syndrome (drug rash) • Toxic Epidermal Necrolysis (severe delayed reaction) • Drug-induced serum sickness • Atopic conditions and hereditary angioedema
- Potential Complications: Severe anaphylaxis (potentially life-threatening), respiratory failure, cardiovascular collapse, shock, death if drug is administered despite positive test results without appropriate precautions.
- Diagnostic Conditions: This test helps diagnose IgE-mediated drug allergy and guides therapeutic decision-making to prevent adverse reactions during future medication administration.
- Follow-up Tests
- Tests Recommended for Positive Results: • Skin Prick Test (SPT) or Intradermal Test: Confirmatory testing with drug allergen • Extended drug allergy panel: Test alternative medications in same drug class • Tryptase levels (total and specific): For anaphylaxis confirmation • Basophil Activation Test (BAT): Functional assessment of allergic response
- Complementary Investigations: • Allergy consultation and detailed history • Patch testing: For delayed hypersensitivity reactions • Graded challenge test: Under medical supervision if needed • Cross-reactivity screening: Related medication classes • Lymphocyte transformation test (LTT): For delayed reactions
- Negative Result Follow-up: Clinical history correlation; if reaction features suggest non-IgE mechanism, skin testing or provocative testing may be warranted. Patient education regarding drug use is safe.
- Monitoring and Ongoing Care: Patients with positive results should carry alert identification (MedicAlert); serial testing rarely needed unless clinical reassessment occurs. IgE levels may decline over years, potentially allowing re-evaluation in specific cases.
- Related Diagnostic Tests: Penicillin G major/minor determinants testing, cephalosporin cross-reactivity panel, fluoroquinolone allergy screening, NSAIDs hypersensitivity testing, acetaminophen allergy assessment.
- Fasting Required?
- Fasting Requirement: No - Fasting is NOT required for drug allergy screening tests by immunoassay.
- Patient Preparation: • No special dietary restrictions • Can eat and drink normally before blood draw • No fluid restriction needed • Test can be performed at any time of day
- Medication Considerations: • Antihistamines (H1/H2 blockers): Should be discontinued 3-7 days before testing to prevent false-negative results on skin tests if planned • Corticosteroids: May mildly suppress IgE levels but generally do not require discontinuation • Beta-blockers: May impair treatment response if anaphylaxis occurs during testing • ACE inhibitors: May increase cough risk; generally safe to continue • No specific medications contraindicated for serum testing; continue regular medications unless directed otherwise
- Special Instructions: • Inform phlebotomist and healthcare provider of specific drug(s) causing allergic reaction • Provide detailed history of allergic symptoms and timing • Inform of any current infections or illnesses that may affect immune status • Note if patient has received immunotherapy or intravenous immunoglobulin (IVIG) recently • Avoid scheduling during acute infection or active allergic reaction • Wear comfortable clothing allowing easy arm access for blood draw
- Timing Considerations: Optimal timing is 2-6 weeks after allergic reaction for highest IgE detection. Testing can be done acutely but may have lower sensitivity. IgE remains detectable for months to years after initial sensitization.
How our test process works!
