This study was conducted to validate enzyme immunoassay (EIA) for the quantitative measurement of human IgG antibodies specific for Haemophilus influenzae type b (Hib) capsular polysaccharide.

We evaluated specificity, repeatability, intermediate precision, accuracy, lower limit of quantification (LLOQ), and stability to validate standardized EIA for the quantitative measurement of human anti-polyribosylribitol phosphate (PRP) IgG antibodies.

The results indicated that this EIA showed specificity to HbO-HA antigen and repeatability and intermediate precision were within acceptance criteria (repeatability: CV ≤15%, intermediate precision: CV ≤20%). The EIA-derived results from this laboratory were equivalent to those obtained by the standard radioactive antigen binding assay (RABA) for quantitation of anti-PRP antibodies in the 28 sera. Spiking recovery result was within acceptance criteria (100±20%). The precision and accuracy of samples in LLOQ were from -14.7 to -4.7% in nominal values, which were within acceptance criteria (precision: CV ≤25%, accuracy: ±25%). Freeze-thaw stability and short term temperature stability were within ±20% of acceptance criteria.

The EIA which is performed at the Center for Vaccine Evaluation and Study Ewha Medical Research Institute, is an appropriate serologic assay which can be used for quantitation of anti-PRP IgG antibodies in human sera.