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11
Anti HBc only Status ?
Isolated anti-HBc — The isolated presence of anti-HBc in the absence of HBsAg and anti-HBs has been reported in 0.4 to 1.7 percent of blood donors in low prevalence areas [10,11] and in 10 to 20 percent of the population in endemic countries [12].
Isolated detection of anti-HBc can occur in three settings:
1. during the window period of acute hepatitis B when the anti-HBc is predominantly IgM class;
2. many years after recovery from acute hepatitis B when anti-HBs has fallen to undetectable levels;
3. after many years of chronic HBV infection when the HBsAg titer has decreased below the cutoff level for detection. As noted above, loss of detectable HBsAg occurs in approximately 0.5 percent of patients with chronic hepatitis B per year [3].
The clinical significance of isolated anti-HBc is unclear. Although HBV DNA has been detected in the serum of individuals with isolated anti-HBc when tested by PCR assays, the frequency of detection varies from 0 to 20 percent [13-15]. HBV DNA can be detected in the liver of most (more than 70 percent) persons with isolated anti-HBc. Transmission of HBV infection has been reported from blood and organ donors with isolated anti-HBc but the incidence ranged widely from 0.4 to 78 percent [15-18]. The risk is highest when liver from anti-HBc positive donors are transplanted.
Studies in the late 1980s suggest that (based upon the development of a primary anti-HBs response to hepatitis B vaccination of asymptomatic individuals with isolated anti-HBc) as many as 50 to 80 percent of persons with isolated anti-HBc have false positive test results [12,14,19].
Nonspecific results appear to be more common with anti-HBc enzyme immunoassays than with radioimmunoassays. However, improvement of enzyme immunoassays in the past decade has decreased the rate of false positive results.
The evaluation of individuals with isolated anti-HBc should include repeat testing for anti-HBc, HBsAg, anti-HBe, and anti-HBs.
Those who remain isolated anti-HBc positive should be tested for the presence of IgM anti-HBc to rule out recent HBV infection.
Presence of anti-HBe indicates that the individual had prior exposure to HBV. Individuals with evidence of chronic liver disease should be tested for HBV DNA to exclude low level chronic HBV infection.
Isolated detection of anti-HBc can occur in three settings:
1. during the window period of acute hepatitis B when the anti-HBc is predominantly IgM class;
2. many years after recovery from acute hepatitis B when anti-HBs has fallen to undetectable levels;
3. after many years of chronic HBV infection when the HBsAg titer has decreased below the cutoff level for detection. As noted above, loss of detectable HBsAg occurs in approximately 0.5 percent of patients with chronic hepatitis B per year [3].
The clinical significance of isolated anti-HBc is unclear. Although HBV DNA has been detected in the serum of individuals with isolated anti-HBc when tested by PCR assays, the frequency of detection varies from 0 to 20 percent [13-15]. HBV DNA can be detected in the liver of most (more than 70 percent) persons with isolated anti-HBc. Transmission of HBV infection has been reported from blood and organ donors with isolated anti-HBc but the incidence ranged widely from 0.4 to 78 percent [15-18]. The risk is highest when liver from anti-HBc positive donors are transplanted.
Studies in the late 1980s suggest that (based upon the development of a primary anti-HBs response to hepatitis B vaccination of asymptomatic individuals with isolated anti-HBc) as many as 50 to 80 percent of persons with isolated anti-HBc have false positive test results [12,14,19].
Nonspecific results appear to be more common with anti-HBc enzyme immunoassays than with radioimmunoassays. However, improvement of enzyme immunoassays in the past decade has decreased the rate of false positive results.
The evaluation of individuals with isolated anti-HBc should include repeat testing for anti-HBc, HBsAg, anti-HBe, and anti-HBs.
Those who remain isolated anti-HBc positive should be tested for the presence of IgM anti-HBc to rule out recent HBV infection.
Presence of anti-HBe indicates that the individual had prior exposure to HBV. Individuals with evidence of chronic liver disease should be tested for HBV DNA to exclude low level chronic HBV infection.
