Occult hepatitis B virus infection in Thai blood donors.
BACKGROUND
An evaluation by the National Blood Center, the Thai Red Cross Society, of two commercial multiplex nucleic acid tests (NATs; the Chiron PROCLEIX ULTRIO test and the Roche Cobas TaqScreen MPX test) for screening Thai blood donors for hepatitis B virus (HBV), hepatitis C virus, and human immunodeficiency virus Type 1 identified 175 HBV NAT-reactive/hepatitis B surface antigen (HBsAg)-negative donors. The classification of the HBV infection of these donors was confirmed by follow-up testing.


METHODS
Index samples were tested for HBV serologic markers and HBV viral loads were determined. Donors were followed for up to 13 months and samples were tested with both NAT assays and for all HBV serological markers.


RESULTS
Of 175 HBV NAT-yield donors, 72 (41%) were followed. Based on the follow-up results, the majority of donors who were followed had an occult HBV infection (66.7%), followed by donors with a primary, acute infection (26.4%). The majority of donors in this latter group (20.8%) were in the window period. Three donors (4.2%), who were anti-HBs positive, had a reinfection or breakthrough infection.


CONCLUSIONS
The majority of donors detected during routine screening, who were HBsAg negative and NAT reactive, had an occult HBV infection, thus validating the decision to introduce NAT for blood donations in Thailand.
Department of Microbiology and Transfusion Medicine, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand. sudaloui@yahoo.com
Suda
S
Louisirirotchanakul
Sineenart
S
Oota
Kalayanee
K
Khuponsarb
Wilai
W
Chalermchan
Soisaang
S
Phikulsod
Viroje
V
Chongkolwatana
Tasanee
T
Sakuldamrongpanish
Pimpun
P
Kitpoka
Pimol
P
Chielsilp
Srivilai
S
Tanprasert
Thaweesak
T
Tirawatnapong
Chantapong
C
Wasi
D001782:Blood Donors; D004279:DNA, Viral / Q000032:analysis; D003951:Diagnostic Errors / Q000517:prevention & control*; D005500:Follow-Up Studies; D006509:Hepatitis B / Q000175:diagnosis*; D006514:Hepatitis B Surface Antigens / Q000032:analysis; D006515:Hepatitis B virus / Q000302:isolation & purification; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D021141:Nucleic Acid Amplification Techniques / Q000379:methods* / Q000592:standards; D012698:Serologic Tests / Q000379:methods; D013785:Thailand / Q000453:epidemiology; D019562:Viral Load / Q000379:methods
D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens