Establishing reference intervals for soluble urokinase plasminogen activator receptor in Northern European adults

Objectives: Soluble urokinase plasminogen activator receptor (suPAR) may have untapped potential in clinical diagnostics. Previous studies determined reference intervals using an enzyme-linked immunoassay, but there is a need for reference intervals using a faster assay if the analysis is to be used in emergency medicine. The current study aims to determine reference intervals for suPAR using a fully automated particle-enhanced turbidimetric immunoassay (PETIA) according to the Clinical and Laboratory Standards Institute guideline A28-A3c. Design and methods: Blood samples were prospectively collected from Danish blood donors. Plasma suPAR was analyzed on the cobas 8000 module c502 in an open channel using a PETIA. Sex-partitioned reference intervals were determined using a parametric quantile approach. Results: The study included 241 participants—123 females and 118 males. The common reference interval for suPAR was 1.56–4.11 ng/mL (95% confidence intervals (CI) for the lower and upper limits were 1.56–1.63 and 3.81–4.47, respectively). The reference interval for females was 1.59–4.65 ng/mL (95% CIs 1.48–1.70 and 4.09–5.48, respectively) and for males, 1.56–3.59 ng/mL (95% CIs 1.47–1.65 and 3.31–3.93, respectively). Conclusions: Our results support using sex-partitioned reference intervals for suPAR and provide a basis for future studies using the PETIA method.