Serological markers of hepatitis B in people submitted to blood testing inhealth care clinics

Objective To study some of the epidemiological aspects of hepatitis B in a non-representative sample of patients seen in health care clinics. Methods The study population comprised 632 patients who were seen at health care clinics in the city of Ribeirao Preto, Brazil, for the purpose of blo od testing, regardless the reason. After signing a written. consent, an add itional amount of blood was drawn from the same venous puncture site used t o collect the original sample for the testing assigned to the patient at th e health car-a clinic. A questionnnaire was applied to each participant, lo oking for the presence of risk factors for hepatitis B. The blood samples w ere tested for HEV markers, using immunoenzimatic techniques. Results The prevalences of HBsAg and anti-HBcAg were 0.3% and 13.9%, respec tively By a logistic regression model, the following variables were signifi cantly associated with the infection: age, time of residency,, in the city (higher risk among those living for a period less than one year), past hist ory of hepatitis, incarceration and sexual behavior (higher risk among homo sexual and bisexual males). Conclusions The growing difficulties in obtaining blood samples from a repr esentative group of patients, as done in classic surveys, make it necessary to look for alternative methodologies which can provide information concer ning the presence of infectious agents in a community. Though the results c annot be generalized to the population as a whole, the methodology used con veyed some knowledge regarding the circulation of hepatitis B virus. In add ition, it makes much easier to obtain agreement from the participants, sinc e is does not add any invasive procedure. Despite the limitations, this met hodology may be helpful in epidemiological surveillance of infectious agent s known as producing asymptomatic infections in much of the the population.