Monitoring liver state with blood tests for patients on methotrexate (MTX)

Monitoring patients on methotrexate: hepatic fibrosis not seen in patients with normal serum assays of aminoterminal peptide of type III procollagen.

Maurice PD, Maddox AJ, Green CA, Tatnall F, Schofield JK, Stott DJ.

Br J Dermatol. 2005 Mar;152(3):451-8.

Methotrexate therapy for conditions such as psoriasis are hepatotoxic. Regular monitoring of liver function is mandatory and fine needle biopsy of the liver is recommended after a cumulative dosage of 1.5g. Although the article was published a few years back it underlines the possibility of measuring liver physiological well-being by measurement of a peptide of type III procollagen (PIIINP) which is formed during the synthesis of type III collagen. It has been suggested that serial assay of PIIINP could reduce or eliminate the need for liver biopsies in these patients. This study was done on 70 biopsies in 38 patients and 306 PIIINP. It shows that assays compared with the results of contemporaneous PIIINP assays follow-up liver biopsies for patients on long-term low-dose methotrexate can be avoided if PIIINP levels are consistently normal. The PIIINP assay is also helpful in the management of patients on methotrexate in whom liver biopsy is contraindicated, and in patients with nonalcoholic steatohepatitis.