Exams and Tests
Chickenpox (varicella) usually can be diagnosed by the
appearance of the
chickenpox rash
. For healthy children, describing the
rash over the phone to a health professional (rather than visiting the office)
may be all that is needed.
However, some people need to see a health professional when
symptoms of chickenpox appear. You are at more risk for complications from
chickenpox if you are a teenager, adult (especially if you smoke cigarettes or
have a long-term lung disease), or a pregnant woman, or you have an
impaired immune system.
If you visit your health professional's office, chickenpox is
diagnosed by
medical history and
physical examination.
Viral tests can determine whether you have
immunity against chickenpox. After you are immune, you
cannot get chickenpox.
If you have a blistering rash, it can be tested to confirm whether
it is caused by the chickenpox virus. This type of testing usually includes
examining:
- Skin cells scraped from inside a blister
(immunofluorescent staining). Results of this test are available in 1 or 2
hours.
- Fluid from inside a blister (viral culture). Results of the
culture are available in 7 to 21 days.
A woman who has chickenpox early in her pregnancy may want to have
her fetus checked for birth defects. This can be done with an
ultrasound of the fetus.
Early Detection
There is no general screening for immunity against chickenpox at
this time. Most people in the United States had chickenpox as children and have
immunity against it.
Some people may be required to be tested for chickenpox immunity.
These include people who work in hospitals, day care centers, schools, and
other areas where chickenpox can easily be passed from one person to another.
Many states now require that children entering day care and school have the
chickenpox
vaccine
(What is a PDF document?) unless they have a doctor's diagnosis or blood test results
that prove immunity.
If you are more likely to get severely ill from chickenpox or to
have
complications of chickenpox, you also need to be
tested to confirm whether you have ever had chickenpox and have immunity
against it. These people include:
- Women who are able to have children. Women
who are pregnant or who want to become pregnant should consider being tested to
see whether they have chickenpox immunity. Having chickenpox immunity prevents
complications of chickenpox during
pregnancy.
- People with impaired immune systems.
If you have never had chickenpox and therefore do not have
immunity against it, you may choose to get the chickenpox vaccine (varicella
vaccine or Varivax). Talk with your health professional about the risks and
benefits of the chickenpox vaccine.