Dual-label time-resolved fluoroimmunoassay for pepsinogen I and pepsinogen II and its preliminary application

A dual-label time-resolved fluoroimmunoassay was established for simultaneously detecting pepsinogen I (PG I) and pepsinogen II (PG II) in human serum. Two capture monoclonal antibodies, 8003(#) of PG I and 8101(#) of PG II, were co-coated in 96 microtitration wells. The counterpart tracer monoclonal antibodies, 8016(#) of PG I and 8102(#) of PG II, were labeled with Eu3+ and sm(3+)-chelates, respectively. The samples were assayed by one-step sandwich protocol with the time-resolved fluorometry. The measurement ranges of PG I were 0.2 similar to 300.0 mu g/L with the within-run and between-run precision was 5.2% and 8.1%, and that of PG II were 0.05 similar to 55.0 mu g/L with the within-run and between-run precision was 7.1% and 11.7%, respectively. The average recovery rates of PG I and PG II were 96.9% and 103.7%, respectively. The results obtained by the dual-label assay agreed well with those by enzyme-linked immunosorbent assays of PG I and PG II, whose correlation ratio were 0.9426 of PG I and 0.9396 of PG II respectively. The means of 300 healthy volunteers were (157.3 +/- 51.0) mu g/L for serum PG I (10.6 +/- 5.9) mu g/L for serum PG II, and (14.8 similar to 4.3) for the PG I /PG II ratio. The normal ranges of serum PG I levels for healthy volunteers were 55.3 similar to 259.3 mu g/L, those of serum PG II levels were less than 23 mu g/L, the PG I /PG II ratio was more than 6. The proposed dual-label TRFIA for simultaneous detection of PG I and PG II is a simple, sensitive, and rapid method. It could provide serology high-screening of the samples for gastric diseases and would allow investigations into the possible diagnostic value of analysis in various clinical condition.