The amino-terminal propeptide of type I procollagen in serum (S-PINP) is a sensitive indicator of type I collagen metabolism in human body. Specifically S-PINP depicts bone tissue synthesis. A measurement of S-PINP helps physicians to follow up spreading tumours with metastases or it can be used for monitoring osteoporosis therapy. Type III collagen can be found in soft tissues. Quantity of amino-terminal propeptide of type III procollagen (S-PIIINP) in serum increases in case of fibrotic diseases or in similar conditions. S-PINP and S-PIIINP are not specific for any certain disease but measurement of those biomarkers can give a physician important information about patients’ health status and effectivity of a treatment.

S-PINP is a validated laboratory assay in NordLab and it is measured as a routine practice by an automatic IDS-iSYS-immunoanalyzer. In spring 2014 a new analysis method was validated for Siemens ADVIA Centaur S-PIIINP assay. The new method has been introduced as a replacement of a previous radioimmunoassay. There are no reference ranges for the new S-PIIINP method.

The reference range project is based on an assignment for NordLab laboratories and aim of the study is to define reference intervals by age and sex, available for Finnish population and S-PINP and S-PIIINP assays. The project is a part of laboratorys own method development and it follows international referenge interval guidelines for clinical laboratories. The new reference intervals are calculated by using applications of mathematical statistics. The reference population is based on surplus serum samples collected from special chemistry laboratory, laboratory for children and service laboratory in NordLab. Exclusion criteria for the reference population is formed considering scientific research and set by specialist doctor. A patient information system ESKO used in Oulu University Hospital is utilized for applying patient health data and selecting suitable reference population for this study.