Hepatitis C virus infection among Thai blood donors: antibody prevalence, risk factors and development of risk screening form.

Hepatitis C virus (HCV) infection is an important blood-borne infection in many countries, including Thailand. For epidemiological surveillance and controlling the infection, 2167 blood donors were screened for antibody to HCV by an enzyme immunoassay method and interviewed by using a structured questionnaire which consisted of personal health history and some risk behaviors. The prevalence and risk factors were assessed and the risk screening form was developed. The results revealed that the prevalence of anti-HCV was 2.90%. Male blood donors had relatively higher anti-HCV positive rate than females (3.21% vs 1.77%). The significant risk factors from univariate analysis were: (a) gender as male, OR = 1.94 (p = 0.042), (b) education to the primary level, OR = 4.15 (p < 0.001), (c) occupation as laborer or agriculture workers, OR = 2.87 (p < 0.001), police and military, OR = 1.82 (p = 0.046), (d) residence in a rural area, OR = 3.09 (p < 0.001), (e) a history of receiving blood or blood products, OR = 5.21 (p < 0.001), (f) a history of tattooing, OR = 1.70 (p = 0.043), (g) a history of IDU (Infecting Drug Use), OR = 41.43 (p < 0.001), (h) a history of STDs (sexually transmitted diseases) in the last year, OR = 3.87 (p = 0.021), and (i) a history of sexual service, OR = 4.24 (p = 0.017). After multivariate analysis, four variables related to HCV infection among the studied samples included education to the primary level, OR = 3.34 (p = 0.0036), occupation as a laborer or agriculture worker, OR = 2.14 (p = 0.0092), a history of receiving blood or blood products, OR = 4.13 (p = 0.0029), and a history of IDU, OR = 3.82 (p < 0.0001). The risk screening form was developed using risk scores. The validity was calculated by the Receiving Operating Curve. The sensitivity of this form was approximately 55.3% and the specificity was 85.7% when a cut-off score at risk > or =7 was used. If the cut-off score was > or =6, the screening form showed 77.1% of specificity and 61.3% sensitivity. This risk screening form should be applied not only for blood donation but also for pre-marital health screening.