To investigate whether high-concentration RFs cause false decrease of S/CO values of serum HBsAg.
Serum HBsAg was determined in 100 RF-positive sera using one-step ELISA. Twenty-three HBsAg-negative sera with high-concentration RFs were selected randomly to perform dilution with mixed normal sera. Serum models consisting of HBsAg and high-concentration RFs were made by blending high-concentration RFs and HBsAg-positive sera at the ratio of 9:1.
In the 23 samples, one-step ELISA showed that HBsAg-positive rate was 69.57% at dilution of 1:2, 60.87% at dilution of 1:4 and 40.00% at dilution of 1:8, whereas two-step ELISA showed that it was 100% without any dilution. Thirty serum models were made and divided into six groups. Median S/CO value of HBsAg was 3.00 in control, whereas it ranged from 0.13 to 1.78 in the six groups.
High-concentration RFs cause false decrease of S/CO values of HBsAg using one-step ELISA.