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Many primary care physicians (PCPs) are not knowledgeable about hepatitis B virus (HBV) screening. According to a 2007 survey of 196 PCPs attending a continuing medical education (CME) meeting, more than half (55%) could not identify the appropriate test to use to diagnose chronic hepatitis B (CHB), and 44% did not know that CHB could be medically treated.1
The rationale for hepatitis B virus (HBV) screening is multifaceted. Chronic hepatitis B (CHB) is a common condition that can be detected by an inexpensive, accurate test. Although treating CHB can prevent the long-term complications of cirrhosis and hepatocellular cancer, treatment cannot be effective unless the infection has been diagnosed. Because CHB is usually clinically silent, approximately two-thirds of individuals with the disease are unaware of their infections.2 Additionally, HBV testing has been shown to be cost-effective in populations with intermediate to high disease prevalence (that is, ≥2%).3 Thus, screening for HBV infection is medically and economically justifiable and is recommended by all relevant guidelines.4-6
The first step in HBV screening is to detect patients with risk factors for the disease. Universal HBV testing is not recommended. Instead, screening is recommended order to identify specific groups of patients who are most likely to benefit from serologic testing. Table 1 lists patient populations for whom HBV testing is recommended.
Table 1. Patient populations for whom HBV testing is recommended4,5
Persons born in geographic regions with an HBsAg prevalence ≥2% |
Infants born to infected mothers |
Household contacts and sexual partners of persons with CHB |
IV drug users |
Sexually active persons not in long-term, mutually monogamous relationships |
Men who have sex with men |
Health care and public safety workers at risk for occupational exposure |
Residents and staff of facilities for developmentally disabled persons |
Persons with chronic liver disease |
Patients undergoing hemodialysis |
Travelers to countries with an intermediate or high prevalence of HBV |
Patients with HIV infection |
CHB, chronic hepatitis B; HBsAg, hepatitis B surface antigen; HBV, hepatitis B virus; HIV, human immunodeficiency virus; IV, intravenous.
Most of the groups recommended for HBV testing have a CHB prevalence of ≥2%, which is considerably higher than that of the general population at <1%. Key among these groups are immigrants from Asia and the Pacific Islands, in whom the prevalence of CHB is approximately 10%. In one study, HBV serologic testing was offered to 3163 Asian American adult volunteers in the San Francisco area between 2001 and 2006.2 Of those tested, 8.9% had CHB and 65.4% of those were unaware of their infection. Those born outside the United States were 19.4 times more likely to have CHB. Similar results have been reported from other metropolitan areas.6
Testing is recommended in some patients because of a specific opportunity to prevent HBV transmission or disease complications. For example, all pregnant women should be tested for CHB, as perinatal transmission can be prevented by aggressive management of the newborn. Moreover, patients who plan to receive immunosuppressive agents should also be tested for CHB because of a 20% to 50% likelihood of a disease flare-up either during or immediately after immunosuppression.8 All patients infected with HIV should be tested as well, both because their risk for CHB is high and because some medications are active against both viruses, rendering it important to be aware of dual infection.
Routine serologic testing for CHB should include testing for the hepatitis B surface antigen (HBsAg) and antibodies to hepatitis B surface antigen (anti-HBs). Use of these two tests provides a simple algorithm (Figure 1). Since at-risk individuals are generally tested, those with negative results for both markers should be vaccinated against HBV. Those with a positive test for anti-HBs are immune to the disease and can be reassured that they do not have HBV and are protected, because of either a prior infection or to previous immunization. People with positive HBsAg tests may have CHB and may require medical management. An essential part of that management is testing all household contacts and sexual partners and providing HBV vaccination to those who are at risk.

Figure 1. Isolated antibody to hepatitis B core antigen and other test outcomes
Anti-HBs, antibodies to hepatitis B surface antigen; HBsAg, hepatitis B surface antigen; HBV, hepatitis B virus.
Some laboratories offer serologic panels that include other tests, such as antibodies to the hepatitis B core antigen (anti-HBc), hepatitis B e antigen (HBeAg), and antibodies to HBeAg (anti-HBe). Anti-HBc is detected after HBV infection but not after vaccination. Thus, anti-HBc can indicate prior resolved infection or CHB. Typically, with resolved infection, anti-HBc is detected along with anti-HBs; whereas in patients with CHB, anti-HBc is detected along with HBsAg. However, occasionally anti-HBc is detected without the presence of either anti-HBs or HBsAg. Such a serologic profile can represent a state of low-level HBV infection known as "occult hepatitis B," or it may represent a false-positive anti-HBc test result.
The former is more likely to occur in persons at high risk for HBV infection, such as those with CHB or HIV; whereas the latter is more often the explanation in low-risk patients, such as those undergoing testing for life insurance. HBV vaccination can be administered to persons with isolated anti-HBc, and some experts will also test for HBV DNA, HBeAg, and anti-HBe.
Like HBsAg, HBeAg is a viral protein whose presence in the blood indicates ongoing HBV infection. HBeAg is cleared before HBsAg, and thus test results can be negative even in persons who have HBsAg in their bloodstream—a state that is referred to as e antigen-negative CHB.
Ideally, HBV screening will be incorporated into the routine of a primary care practice. However, there may be insufficient time during a routine PCP visit to screen for HBV risk factors and to follow dozens of other guidelines as well. In addition, patients may be reluctant to disclose past behaviors that place them at risk for HBV. Thus, it best to use a nonthreatening method to identify patients who might benefit from HBV testing. Inclusion of risk groups in questionnaires completed by patients before a medical visit, simple checklists, and other methods have been examined. The guidelines for HBV testing and vaccination practices are sufficiently clear to be ideal quality assurance measures. Ultimately, all providers must determine the best way to screen for CHB in their practices, and then implement the procedure, and monitor its effectiveness.
Commentary References
1. |
Dulay M, Zola J, Hwang J, Baron A, C. Lai C. Are primary care clinicians knowledgeable about screening for chronic hepatitis B infection? Presented at: 30th Annual Meeting of the Society of General Internal Medicine (SGIM). Toronto, Canada. J Gen Intern Med. 2007;22(suppl 1):100. |
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2. |
Lin SY, Chang ET, So SK. Why we should routinely screen Asian American adults for hepatitis B: a cross-sectional study of Asians in California. Hepatology. 2007;46(4):1034-1040. |
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3. |
Hutton DW, Tan D, So SK, Brandeau ML. Cost-effectiveness of screening and vaccinating Asian and Pacific Islander adults for hepatitis B. Ann Intern Med. 2007;147(7):460-469. |
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4. |
Lok AS, McMahon BJ. Chronic hepatitis B: update 2009. Hepatology. 2009;50(3):661-662. |
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5. |
Colvin HM, Mitchell AE, eds. Hepatitis and Liver Cancer: A National Strategy for Prevention and Control of Hepatitis B and C. Washington, DC: Committee on the Prevention and Control of Viral Hepatitis Infections; Institute of Medicine. The National Academies Press. Accessed February 14, 2011. |
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6. |
Centers for Disease Control and Prevention (CDC). Screening for chronic hepatitis B among Asian/Pacific Islander populations--New York City, 2005. MMWR Morb Mortal Wkly Rep. 2006;55(18):505-509. |
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7. |
Centers for Disease Control and Prevention (CDC). Recommendations for identification and public health management of persons with chronic hepatitis B virus infection. MMWR Morb Mortal Wkly Rep. 2008;57(RR-8):1-20. |
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8. |
Yeo W, Chan PK, Zhong S, et al. Frequency of hepatitis B virus reactivation in cancer patients undergoing cytotoxic chemotherapy: a prospective study of 626 patients with identification of risk factors. J Med Virol. 2000;62(3):299-307. |
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