HCV screening in blood donations using RT-PCR in mini-pool: the experience in Spain after routine use for 2 years

The aim of this study is to evaluate the feasibility of implementing a commercial HCV RNA RT-PCR screening method and provide data on the prevalence and incidence rates of hepatitis C in Spain.

Five transfusion centers participated in the study, covering 34.1 percent of the country's total number of donations. All the centers evaluated the sensitivity and characteristics of a commercial RT-PCR reagent kit designed for pool testing (Cobas AmpliScreen HCV v2.0), for which serial dilutions of HCV WHO International Standard 96/790 and preseroconversion samples were used. The data obtained from this technique, employed routinely from May 1999 to June 2001 in 22- to 48-unit mini-pools, are presented in this study.

An overall 95-percent detection limit was obtained either at 69 IU per mL when 0.2 mL volume of plasma was extracted (used to analyze individual units), or at 20 IU per mL, when viral particles were pelleted from 1 mL plasma (as used for screening in mini-pool) Three HCV-RNA-positive anti-HCV-negative donations were identified out of 1,015,482 screened donations. One of these had an initially undisclosed risk of HCV sexual transmission and carried a low viral load of 104.2 IU per mL HCV RNA. The analysis of first-time (FT) donations during the period of study (21.3% of the total) indicated an average prevalence rate of 2.05 per 103 FT donors (of which 1.55/103 FT donors were RNA positive); the residual risk calculated on repeat (RPT) donors was 3.91 per 106 donations (serology) or 0.59 per 106 donations (serology + NAT), and the predicted NAT yield estimate was 4.2 per 106 FT + RPT donations.

The commercial RT-PCR reagent kit complies with the current European and FDA recommendations on sensitivity and can be easily implemented on a routine basis. The results obtained by the five transfusion centers on the predicted NAT yield (1/302,000 RPT donations or 1/237,000 FT + RPT donations) are very close to the published estimates corresponding to a larger area of our country (1/237,000 RPT donations) and are somewhat higher than, though in line with, the observed NAT yield (1/338,000 FT + RPT donations).