RESUMO
BACKGROUND: The clinical utility of serum periostin as a type 2 biomarker in asthma is limited by lack of reference range values derived from a population without respiratory disease. OBJECTIVE: To derive age- and sex-related reference intervals for serum periostin from an adult population without asthma or COPD. METHODS: Serum periostin levels were measured in 480 individuals, comprising 60 female and 60 male adults in each of the 18- to 30-year, 31- to 45-year, 46- to 60-year and 61- to 75-year age groups. Key exclusion criteria included a doctor's diagnosis of asthma, chronic bronchitis or COPD, and a history of wheezing or use of respiratory inhalers in the last 12 months. The distribution of periostin and logarithm-transformed periostin levels was derived, and 90% confidence intervals for an individual prediction were calculated. RESULTS: The distribution of serum periostin was right skewed with a mean (SD) periostin of 51.2 (11.9) ng/mL, median (IQR) 50.1 (43.1 to 56.9) ng/mL and range 28.1 to 136.4 ng/mL. There was no association between logarithm periostin and age or sex, although levels were low in current smokers. The 90% confidence limits for periostin were 35.0 and 71.1 ng/mL. CONCLUSIONS AND CLINICAL RELEVANCE: Serum periostin levels in adults without asthma or COPD are similar to those in adults with asthma. Serum periostin measurements do not need to be adjusted to take account of a patient's age or sex, although levels are lower in current smokers. Reference values for serum periostin levels in adults without asthma or COPD are provided.