The establishment and validation of reference intervals for plasma Pentraxin-3 in healthy volunteers and patients with Takayasu's arteritis

Abstract

Background and aims: To establish reference intervals (RIs) for PTX-3 and to validate the performance of these RIs in a population including healthy volunteers and Takayasu's arteritis (TAK) patients.

Materials and methods: Plasma PTX-3 levels were determined in 166 healthy volunteers and 63 TAK patients. RIs were established in healthy volunteers according to guidelines from the Clinical and Laboratory Standards Institute (CLSI, C28-A3). Global assessment was used to quantitatively diagnose active/non-active TAK patients. Screening and monitoring performances were validated by identifying active TAK patients from the whole population or diagnosed TAK patients.

Results: The PTX-3 RI was calculated to be 0.87-2.78 ng/mL. For screening purposes, 1.55 ng/mL had a high sensitivity of 90.32 % and the RI upper limit (2.78 ng/mL) had a high specificity of 97.94 %. For monitoring purposes, the sensitivity/specificity of the cut-off value (1.55 ng/mL) and RI median were 90.32 %/90.63 % and 80.85 %/90.63 %, respectively. These screening and monitoring performances of PTX-3 were superior to those of C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR).

Conclusion: The distribution of serum PTX-3 levels was stable and uniform across the population. The screening and monitoring performances of the cut-off value and RI-derived values of PTX-3 were higher than CRP and ESR.

Keywords: Clinical validation; Cut-off values; Pentraxin-3; Reference intervals; Takayasu's arteritis.