Identification of low HBV-DNA levels by nucleic acid amplification test (NAT) in blood donors.
OBJECTIVE
To evaluate the presence of HBV-DNA in 22,765 consecutive blood donors, who donated blood in the period from January 2006 to August 2007 at a transfusion centre in Lazio, a region in central Italy with low HBV endemicity.


METHODS
Each donation was individually tested using immunoenzymatic assays and nucleic acid amplification technologies (NAT). Samples that were reactive to generic NAT, Procleix Ultrio Assay were tested for HBV-DNA, HCV-RNA and HIV1-RNA by Discriminatory Procleix Ultrio NAT Assay. In samples that were reactive to generic NAT and negative for HBsAg, HCV-RNA and HIV1-RNA, HBV-DNA was further tested using Cobas TaqMan and an in-house nested PCR following an ultracentrifugation step. Sequence analysis confirmed HBV-DNA positivity.


RESULTS
Generic NAT identified 31 (0.13%) reactive sera. HBV-DNA discriminatory NAT identified 15 positive sera; HBsAg was positive in 12 sera. Of the 5 generic NAT-reactive/discriminatory NAT-negative/HBsAg-negative sera and of the 3 HBsAg-negative/HBV-DNA discriminatory NAT-positive sera, 7 were positive to Cobas TaqMan or the in-house PCR after ultracentrifugation. The overall HBV-DNA positivity was 0.083% [19 of 22,765 donors: 12 HBsAg-positive (HBV-DNA range 10(2)-10(4) IU/mL), 7 HBsAg-negative/anti-HBc positive (HBV-DNA< 6 IU/mL)].


CONCLUSIONS
For blood transfusion safety, the significance of the finding of very low HBV-DNA levels should be further investigated. Our data indicate that in areas with a low HBV endemicity, single NAT assays may not always identify blood donations with very low HBV-DNA levels.
Dettori
Stefano
S
Viral Hepatitis Unit, Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, 00161 Rome, Italy.
Candido
Angela
A
Kondili
Loreta A
LA
Chionne
Paola
P
Taffon
Stefania
S
Genovese
Domenico
D
Iudicone
Paola
P
Miceli
Michelina
M
Rapicetta
Maria
M
D000328:Adult; D001769:Blood / Q000821:virology*; D001782:Blood Donors; D004279:DNA, Viral / Q000235:genetics / Q000302:isolation & purification*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D015497:HIV-1 / Q000235:genetics / Q000302:isolation & purification; D016174:Hepacivirus / Q000235:genetics / Q000302:isolation & purification; D006515:Hepatitis B virus / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D012367:RNA, Viral / Q000235:genetics / Q000302:isolation & purification; D012680:Sensitivity and Specificity; D055815:Young Adult
D004279:DNA, Viral; D012367:RNA, Viral