A systematic review of total IgE reference intervals - A 2024 update

Area of Science:

• Clinical Chemistry
• Immunology
• Allergy Diagnostics

Background:

• Total IgE (tIgE) testing is common for atopy symptoms, but its diagnostic utility is limited.
• Accurate reference intervals for tIgE are crucial for clinical interpretation, yet current intervals may be outdated.
• This systematic review addresses the need for updated tIgE reference intervals.

Approach:

• A systematic literature search was conducted across major databases (MEDLINE, Embase, Cochrane Library) up to July 2024.
• Studies providing paediatric and/or adult tIgE reference intervals using current immunoassays were included, following PRISMA guidelines.
• The study protocol was registered with PROSPERO (CRD42023396441).

Key Points:

• 20 studies involving 23,910 individuals across 18 countries were analyzed.
• Significant variation in upper reference limits was observed.
• Participant selection criteria and statistical methods were identified as key factors influencing upper reference limits.

Conclusions:

• Laboratories must critically assess participant selection and statistical methods when establishing tIgE reference intervals.
• Harmonization and improved reporting of tIgE reference interval studies are necessary.
• Ensuring appropriate tIgE reference intervals aids clinicians in interpreting patient results.