The amino-terminal peptide of type 3 procollagen (P3NP) is formed during the synthesis of type 3 collagen. Serum P3NP is used as a marker for hepatic fibrosis in patients on long-term, low-dose methotrexate.
Monitoring of patients receiving low-dose methotrexate therapy.
SST (gold top) or serum (red top)
Up to 2 weeks
Not currently performed in house; this is a referred test.