What blood test is used to diagnose an allergy to bee venom?

Diagnostic Blood Tests for Bee Venom Allergy

The primary blood test for diagnosing bee venom allergy is serum venom-specific IgE testing, which should be ordered when skin testing is not feasible or as a complementary test to confirm skin test results. 1

Primary Diagnostic Approach

Venom-Specific IgE Blood Testing

• Serum venom-specific IgE antibody testing is the standard blood test for diagnosing bee venom allergy 1
• Testing should include all commercially available venoms (honeybee, yellow jacket, hornet, wasp, and where relevant, fire ant) 1
• Blood testing is particularly valuable when:
  • Skin testing is contraindicated (severe dermatological conditions)
  • Patients are taking medications that interfere with skin testing
  • Skin test results are negative despite a convincing history 1

Timing of Testing

• Optimal timing: 3-6 weeks after a sting reaction
• Testing too early (within first few weeks after sting) may yield false negatives
• One study found that 79% of allergic patients could be identified at 1 week post-sting when both skin and blood tests were performed, while the remaining 21% required repeat testing at 4-6 weeks 1

Component-Resolved Diagnostics

• Modern testing includes component-resolved diagnostics using recombinant allergens 2
• Testing for specific bee venom components increases diagnostic sensitivity:
  • rApi m1 (phospholipase A2)
  • rApi m3
  • rApi m10
• Adding rApi m10 and rApi m3 to testing panels significantly improves diagnostic sensitivity 2

Interpretation Considerations

• No absolute correlation exists between IgE antibody levels and severity of clinical symptoms 1
• Some patients with severe reactions may have barely detectable venom IgE levels 1
• False negatives can occur:
  • Even with negative blood and skin tests, rare anaphylactic reactions to subsequent stings have been reported 1
  • Consider non-IgE-mediated mechanisms in these cases

Additional Testing in Special Cases

• Baseline serum tryptase levels should be measured in:

  • Patients with severe anaphylactic shock reactions
  • Patients with negative skin/blood tests despite convincing history
  • Elevated tryptase may indicate mastocytosis or mast cell disorders 1

• IgG antibody testing is not routinely recommended:

  • IgG levels do not correlate with protection from stings 3
  • High IgG levels may actually interfere with IgE detection 4

Clinical Management After Diagnosis

• Patients with positive venom-specific IgE and history of systemic reaction should be referred for venom immunotherapy (VIT) 5
• VIT reduces risk of subsequent systemic reactions to as low as 5% 5
• All patients with history of systemic reactions should carry autoinjectable epinephrine 5

Common Pitfalls to Avoid

1. Relying solely on blood tests: Skin testing remains the gold standard; blood tests should complement, not replace skin testing when possible 1

2. Testing too soon after a sting: May yield false negatives; optimal timing is 3-6 weeks post-sting 1

3. Testing only for the suspected culprit: Cross-reactivity exists between venoms; comprehensive testing for all available venoms is recommended 1

4. Misinterpreting IgG levels: High IgG antibody levels do not indicate protection and may interfere with IgE detection 4, 3

5. Overlooking mastocytosis: Patients with severe reactions and negative tests should be evaluated for underlying mast cell disorders 1