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Blood Test Tracker

German Cockroach IgE

Measures IgE antibodies to German cockroach, an indoor allergen linked to year-round nose and eye symptoms and to asthma.

AI-verified against cited sources. Awaiting expert reviewAlso called i6, i006LOINC 6078-0

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What it is

This test measures IgE antibodies to German cockroach (Blattella germanica, ImmunoCAP i6), the cockroach most common in homes in temperate climates. The allergens come from cockroach saliva, droppings, eggs and shed skin, which mix into household dust, and you mostly breathe them in. Sensitization to cockroach is linked to year-round allergy symptoms and to asthma, particularly in children in cities.

Why it matters

If you have asthma or year-round nose and eye symptoms, a detectable result can help your clinician think about indoor triggers. In a large study of inner-city children with asthma, those who were both allergic to cockroach and exposed to high levels of it at home had more hospital stays and unplanned visits for asthma. A detectable result does not prove cockroach is behind your symptoms, so it is read with your history and your home.

If it’s high

A level above your lab's range means your body has made more IgE to German cockroach. It shows sensitization, which can happen with or without symptoms. The class number describes how much IgE was found, not how bad your symptoms will be.

Common causes

  • Allergy to cockroach allergens, often with year-round nasal symptoms or asthma
  • Past or current exposure to cockroach allergen at home, school or work
  • Sensitization without any symptoms
  • IgE that also reacts with similar proteins in other cockroach species, dust mites or shellfish
  • A very high total IgE (above about 2,500 kU/L), which can cause a false-positive reading

What can help

  • Ask your clinician about ways to cut off food for cockroaches, such as storing food in airtight containers, cleaning up crumbs and spills right away, and sealing cracks and openings
  • Ask about pest control that carries less risk than insecticides, and follow the product label if you use any pesticide
  • Ask whether your asthma plan, if you have one, covers indoor triggers like this

Usual ranges

What labs print as the reference range, by who was tested. Ranges differ a little between labs, so the range on your own report is the one your result is judged against.

For adults: 0–0.09 kU/L. Source: Mayo Clinic Laboratories, ARUP Laboratories, U.S. Food and Drug Administration.

ImmunoCAP IgE classes (Mayo Clinic Laboratories wording)

  • Class 0: negativebelow 0.1 kU/L
  • Class 0/1: borderline or equivocal0.1 to under 0.35 kU/L
  • Class 1: equivocal0.35 to under 0.7 kU/L
  • Class 2: positive0.7 to under 3.5 kU/L
  • Class 3: positive3.5 to under 17.5 kU/L
  • Class 4: strongly positive17.5 to under 50 kU/L
  • Class 5: strongly positive50 to under 100 kU/L
  • Class 6: strongly positive100 and above kU/L

What can affect your result

  • Where you live and work: cockroach allergen levels in dust vary a lot between buildings
  • Cross-reactivity with other cockroach species, dust mites and shellfish proteins
  • A very high total IgE (above about 2,500 kU/L) can cause false-positive results
  • The lab and test brand, because results from different systems are not directly comparable
  • A very high total IgE (above about 2,500 kU/L) can cause false-positive results through nonspecific binding (Mayo Clinic Laboratories).
  • Different labs and test brands give different numbers for the same blood sample, so compare results from the same lab and system.
  • Some labs reject hemolyzed, icteric or lipemic samples (ARUP).

Slow. It usually shifts over months to years, not weeks.

When to talk to a clinician

Talk with a clinician soon if you have wheezing, chest tightness or shortness of breath that does not ease with your usual asthma plan. Call 911 or your local emergency number for severe trouble breathing.

Questions you could ask

  • Would other indoor allergen tests, such as dust mite, be useful?
  • Could cockroach allergen at home, school or work be adding to my symptoms or asthma?
  • Does my asthma plan cover indoor triggers like this?

Questions people ask

I have not seen cockroaches at home. Why is my result positive?

A detectable result shows your immune system has made IgE to cockroach. It does not mean you have an infestation. IgE can also react to similar proteins in other cockroach species, dust mites and shellfish.

Does a positive result mean cockroaches are causing my asthma?

Not on its own. Cockroach allergy is one of several indoor triggers linked to asthma. Your clinician looks at your symptoms, when and where they happen, and your other test results.

Show the science and sources

For clinicians and researchers

Quantitative IgE to a German cockroach extract (Blattella germanica, ImmunoCAP i6). Reported as allergen-specific IgE by ImmunoCAP fluoroenzyme immunoassay in kUA/L, with calibrators traceable to the WHO IgE reference (IRP 75/502). The FDA-reviewed system has a limit of quantitation of 0.1 kUA/L and reports up to 100 kUA/L; its maker recommends a 0.35 kUA/L cutoff and tells each lab to set its own range (FDA review K173726). Allergens come from saliva, feces, eggs and shed skin in dust, and inhalation is the main route. Characterized allergens include Bla g 1, Bla g 2, Bla g 4 (a lipocalin), Bla g 5 and Bla g 7 (tropomyosin); Bla g 7 shares about 80% homology with other invertebrate tropomyosins, which can produce cross-reactivity with shellfish and dust mites, and cross-reactivity with American cockroach allergens is also described (Thermo Fisher). The whole-extract test does not separate these. Skin-test sensitization together with high bedroom allergen levels was linked to more asthma hospitalizations and unscheduled visits in inner-city children (Rosenstreich 1997). A positive result shows sensitization, not clinical allergy. Nonspecific binding can cause false positives when total IgE exceeds about 2,500 kU/L (Mayo).

LOINC 6078-0 (primary), 112145-8. Specimen: serum.

Sources

  1. Cockroach, IgE, Serum (test ID COCR), Mayo Clinic Laboratories
  2. Allergen, Insects and Venom, Cockroach, German (ARUP test 0055088), ARUP Laboratories
  3. Cockroach, German (I006-IgE Cockroach, German) (Labcorp test 602488), Labcorp
  4. ImmunoCAP Specific IgE (allergen component f447) 510(k) decision memorandum K173726, U.S. Food and Drug Administration
  5. i6 Cockroach, German (Allergen Encyclopedia), Thermo Fisher Scientific (Phadia)
  6. The role of cockroach allergy and exposure to cockroach allergen in causing morbidity among inner-city children with asthma, New England Journal of Medicine (1997)
  7. Asthma Triggers: Gain Control (cockroaches and pests), U.S. Environmental Protection Agency
  8. Specific IgE antibody criteria for Japanese cedar, Uni-CAP method (Appendix 3, in Japanese), Ministry of the Environment, Japan
  9. Allergy Testing units (LOINC Community Forum thread), Regenstrief Institute, LOINC Community Forum

AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.

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