Procollagen-3 N-Terminal Peptide (PIIINP, P3NP)


Procollagen-3 N-Terminal Peptide (PIIINP, P3NP)

Site(s) or Laboratory offering Test/Investigation





The decision to perform biopsy, withdraw treatment, or continue treatment despite raised PIIINP concentrations, must also take into account other factors, such as disease severity, patient age, and the ease with which alternative therapies may be used in place of methotrexate.

Storage conditions and sample stability between collection and transport to Lab

Send at RT

Sample type

Serum (0.6 ml minimum)

Turnaround times (TAT) Urgent/Routine/GP or OPD

4-6 weeks

Reference intervals (adult unless stated)

Indications for liver biopsy
Pre-treatment > 13.0 ug/L
During treatment > 7.0 ug/L in at least 3 samples over 12 months
During treatment > 13.0 ug/L in 2 consecutive samples

Indications for withdrawal of methotrexate:
During treatment > 17.0 ug/L in at least 3 samples over 12 months


The Manchester criteria, modified for the positive bias on the Siemens assay