Abstract:
BACKGROUND : Neopterin, a product of cell-mediated immunity, is a non-specific biomarker of inflammation. Plasma/serum is
generally the body fluid of choice for neopterin assessment, but urine is often used as it does away with venepuncture. Analysis
of urine neopterin is based on collection of a single urine sample and expressed as μmol neopterin/mol creatinine.
OBJECTIVES : To examine published correlations between plasma neopterin levels and urine neopterin:creatinine ratios and to
determine whether they are in diagnostic agreement.
METHODS : Literature search was performed by databases and by hand. Databases included Academic Search Complete; Africa-
Wide Information; AHFS Consumer Medication Information; eBook Collection (EBSCOhost); Family & Society Studies
Worldwide; MasterFILE Premier; MEDLINE; TOC Premier.
RESULTS : Positive correlations of varying statistical significance generally exist between plasma neopterin and urine neopterin:
creatinine ratios. With a decline in renal clearance, plasma neopterin over-estimates inflammatory activity. With immune-complex
renal disease, urine neopterin:creatinine ratios over-estimate systemic inflammation. The two biomarkers can differ in
diagnostic validity.
CONCLUSION : Correlations between plasma neopterin and urine neopterin:creatinine ratios suggest both as suitable biomarkers.
However, since correlations reflect equality of means and not individual values, significant correlations, do not necessarily imply
diagnostic agreement. Therefore, plasma and urine cannot summarily be assumed interchangeable for diagnostic/prognostic
purposes.
