Sorted By Test Name - Mayo Medical Laboratories

PBPR
8621
Interpretation: Hepatitis A Antibody against hepatitis A antigen (anti-HAV) is almost always
detectable by the onset of symptoms (usually 15-45 days after exposure). The initial antibody consists
almost entirely of the IgM subclass of antibody. Anti-HAV IgM usually falls to undetectable levels 3 to 6
months after infection. Anti-HAV, IgG levels rise quickly once the virus is cleared and persist for many
years. Hepatitis B Hepatitis B surface antigen (HBsAg) is the first serologic marker appearing in the
serum 6 to 16 weeks following hepatitis B virus (HBV) infection. In acute cases, HBsAg usually
disappears 1 to 2 months after the onset of symptoms. Hepatitis B surface antibody (anti-HBs) appears
with the resolution of HBV infection after the disappearance of HBsAg. Anti-HBs also appears as the
immune response following a course of inoculation with the hepatitis B vaccine. Anti-HBc appears
shortly after the onset of symptoms of HBV infection and may be the only serologic marker remaining
years after exposure to hepatitis B. Hepatitis C Hepatitis C antibody (anti-HCV) is usually not detectable
during the early months following infection, but is almost always detectable by the late convalescent stage
of infection. Anti-HCV is not neutralizing and does not provide immunity.
Reference Values:
HEPATITIS B SURFACE ANTIGEN
Negative
HEPATITIS B SURFACE ANTIBODY, QUALITATIVE/QUANTITATIVE
Hepatitis B Surface Antibody
Unvaccinated: negative
Vaccinated: positive
Hepatitis B Surface Antibody, Quantitative
Unvaccinated: or =12.0
HEPATITIS B CORE TOTAL ANTIBODIES
Negative
HEPATITIS A TOTAL ANTIBODIES
Negative
HEPATITIS C ANTIBODY SCREEN
Negative
Interpretation depends on clinical setting. See Viral Hepatitis Serologic Profiles in Special Instructions.
Clinical References: Hochman JA, Balistereri WF: Viral hepatitis: expanding the alphabet. Adv
Pediatr 1999;46:207-243
Primidone and Phenobarbital, Serum
Clinical Information: Primidone is used for control of grand mal seizures that are refractory to other
antiepileptics and seizures of psychomotor or focal origin. Primidone is initially dosed in progressively
increasing amounts starting with 100 mg at bedtime to 250 mg t.i.d. after 10 days of therapy in adults.
Primidone exhibits a volume of distribution of 0.6 L/kg and a half-life of 8 hours. When monitoring
primidone and phenobarbital levels simultaneously, the specimen should be drawn just before the next
dose is administered. Primidone is not highly protein bound, approximately 10%. Phenobarbital is a
metabolite of primidone. Like phenobarbital, there are no known major drug-drug interactions that affect
the pharmacology of primidone. Toxicity associated with primidone is primarily due to the accumulation
of phenobarbital. Diagnosis and treatment are as described for PBAR Phenobarbital, Serum.
Useful For: Assessing compliance Monitoring for appropriate therapeutic level Assessing toxicity
Interpretation: At steady-state, which is achieved approximately 2 weeks after therapy is initiated,
blood levels of primidone that correlate with optimal response to the drug range from 9.0 to 12.5 mcg/mL
for adults and 7.0 to 10.0 mcg/mL for children